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ECBC-User-Guide(30th March) - ECO-III

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1. Any Solid Material Wall Roof or Floor A single solid material illustrates the transfer of heat from the warmer to the cooler particles by conduction 1 Air Cavity in a Wall As air is warmed by the warmer side of the air space it rises As it falls down along the cooler side it transfers heat to this surface 2 Radiant energy 3 is transferred from the warmer to the cooler surface The rate depends upon the relative temperature of the surfaces and upon their emissive and absorptive qualities Direction is always from the warmer to the cooler surface An air cavity in a Roof or Floor The convective action 2 in the air space of a roof is similar to that in a wall although the height through which the air rises and falls is usually less The radiant transfer 3 is in the upwards direction in this case because the direction is always to the cooler surface When the higher temperature is at the top of a horizontal air space the warm air is trapped at the top and being less dense than the cooler air at the bottom will not flow down to transfer it s heat to the cooler surface This results in little flow by convection The radiant transfer in this case 3 is in the downward direction because that is the direction from the warmer to the cooler Source Stein Reynolds 2000 Mechanical and Electrical Equipment for Buildings CLII 2 1 2 Heat Flow through Conduction Thermal conduction is the process transfer of heat from
2. Conctrete sandwich panel ke af SIPS Table IV 10 U factors gt of Structurally Insulated Wall Table IV 14 Properties of Epi Panels SIPS Concrete Sandwich Aad Ar Panels ya 5 x ARRETE fax Wood Spacers OSB Spline A Spandrel panel Table IV 15 U factors for Spandrel Panels and Glass Curtain Walls Metal frame Table IV 11 U factors of Metal Framed Walls F Masonry Table IV 12 Metal walls Table I V 16 Properties of Hollow Unit U factors for Metal Masonry Walls Building1 Walls S Source ACM Joint Appendix IV FAQs 3 Water migration through Opaque Elements How does water get migrated Water intrusion from the exterior rain and snow can enter the wall in two ways bulk water and air transported moisture If the wall is not allowed to dry in a reasonable amount of time the moisture content can rise and cause rotting mold or mildew Air transported moisture occurs when air leaks from the warm side of the wall to the cool side Warm air holds higher amounts of water vapor than cold air As warm air travels through a wall heading to the cold side it will begin to cool and be forced to release moisture This is called the dew point where condensation will occur When there is a significant temperature drop across the wall the dew point temperature will occur somewhere within the wall In the winter months in cold and moder
3. Coefficient of Performance COP is the ratio between useful energy acquired and energy applied and can be expressed as COP E E where COP coefficient of performance E useful energy acquired E energy applied COP can be used to define both cooling efficiencies and heating efficiencies as for heat pumps Cooling COP is defined as the ratio of heat removal to energy input to the compressor Heating COP is defined as the ratio of heat delivered to energy input to the compressor COP can be used to define the efficiency at single standard or non standard rated conditions or as a weighted average of seasonal conditions The term may or may not include the energy consumption of auxiliary systems such as indoor or outdoor fans chilled water pumps or cooling tower systems The higher the COP the more efficient is the system COP can be treated as an efficiency where COP of 2 00 200 efficiency For unitary heat pumps ratings at two standard outdoor temperatures of 8 3 C and 8 3 C are typically used Energy Efficiency Ratio EER The Energy Efficiency Ratio EER is a term generally used to define cooling efficiencies of unitary air conditioning and heat pump systems The efficiency is determined at a single rated condition specified by an appropriate equipment standard and is defined as the ratio of net cooling capacity or heat removed in B u to the total input rate of electric energy applied in watt hour
4. SYSTEM amp IT S Use accurate heating amp cooling load calculations to COMPONENTS avoid ovet sizing or under sizing system Plan amp make provisions for future building expansions CONSIDER PART LOAD Peak load conditions historically occur only 1 2 5 PERFORMANCE SELECTION of the time Select systems that can operate CRITERIA efficiently at part load Eg Variable capacity boilers chillers compressor equipment pumps motors and use temperature reset controls for hot water chilled water and supply air PERFORM SYSTEM COMMISSIONING Test the HVAC systems under all aspects of operation to reveal and rectify problems thereby ensuring that the system performs as intended ESTABLISH AN OPERATIONS amp Make systems control operations amp maintenance MAINTENANCE O amp M PROGRAM training a part of the construction contract Establish a written comprehensive O amp M program for all equipment and system controls based on the requirements of the facility equipment and systems installed HVAC Basics Heating Ventilation and Air Conditioning HVAC systems employ the same operating principles and basic components as a refrigerator An air conditioner cools with a cold indoor coil called the evaporator The condenser a hot outdoor coil releases the collected heat outside The evaporator and condenser coils are serpentine tubing surrounded by aluminum fins This tubing is usually made of copper A pump called the compresso
5. The Solar Heat Gain Coefficient SHGC is a measure of the percentage of heat from the sun 52 that gets through a window or other fenestration product The SHGC is expressed as a number between 0 and 1 The lower a window s SHGC the less solar heat it transmits to the interior of the building SHGC can also refer to shading so the lower the SHGC the more effective the product is at shading the heat gain from entering the interior What is low e glass Low e stands for low emissivity and refers to a special coating that reduces the heat transfer of a window assembly Low e coated products that reduce solar heat gain can be produced by adding a metallic coating either while the glass is in a molten state or by applying to the glass after it has cooled to a solid state Low e glass is readily available from all the glass and window manufacturers The coatings typically add about 10 to the cost of a window but costs vary by product type by manufacturer by retailer and by location What is spectrally selective glass The sun emits visible solar radiation in the form of light and infra red radiation that cannot be seen but causes heat Spectrally selective glass transmits a high proportion of the visible solar radiation but screens out radiant heat from the sun significantly reducing the need to cool a building s interior Spectrally selective glass is used to describe low e coated glass that lowers the SHGC How can I be sure I h
6. Total Allowed Watts 17 000 Note that in the above example only Column B or Column C can be used to determine the allowed lighting power qualify project Do not use more than one column 7 3 3 Space Function Method Similar to the building area method the first step of the space function method is to determine the appropriate building type and their allowed lighting power densities which varies according to the function of the space These are listed in ECBC Table 7 2 Interior Lighting Power Space Function Method See Error Reference source not found 9 Table 29 Table 28 ECBC Table 7 2 Interior Lighting Power Space Function Method 01 Fornos i e rowe sore eeo Formus fe wey o Space Function For Reading Area Hospital For Emergency For Recovery For Nurse Station For Exam Treatment For Pharmacy For Patient Room For Operating Room For Nursery For Medical Supply For Physical Therapy For Radiology For Laundry Washing Automotive Service Repair Manufacturing Facility For Low Bay lt 8m ceiling For High Bay gt 8m ceiling For Detailed Manufacturing For Equipment Room For Control Room Hotel Motel Guest Rooms Dormitory Living Quarters Museum For General Exhibition For Restoration Bank Office Banking Activity Area Retail For Sales Area For Mall Concourse Sports Arena For Ring Sports Area For Court Sports Area For Indoor Field Area Warehouse For Fine
7. 0 35 to 0 60 0 20 0 25 Vertical Glass Windows SHGC Lighting Power Density in 10 8 11 10 8 7 ot 10 w m Notes This table assumes that we are comparing a 10 story commercial office building in similar climate zones in each country The representative cities used for the comparison are Miami in the U S Hainan Province in China and New Delhi in India SHGC stands for solar heat gain coefficient and it represents the ratio of solar heat that can penetrate through a window WWR stands for window to wall ratio Sources ASHRAE 90 1 2007 ECBC 2007 China s Design Standards for Energy Efficiency of Public Buildings 2005 and the Building Code of Australia 2007 In general the lower the number represented in this chart the more efficient the component will be However because this chart is looking at one building type in one climate zone extrapolating these results to a national level requires some care For example the U S U values shown are quite different than the requirements applicable in other U S climate zones where more efficient envelopes are mandatory Means of Attaining Compliance Building energy standards typically provide property owners with some degree of flexibility in meeting the energy efficiency requirements This is important because it means that the standard can be mote stringent without impinging too severely on the ability of property owners to adapt buildings to their needs There are several approach
8. Figure 26 Cube Law Equation The cube law can be demonstrated with the following equations Figure 26 that apply to fluid flow Our example is for a fan but the equations apply to any fluid moved by turbo machinery against purely frictional resistance Thus 6354Nn fan powert is proportional to fluid velocity cubed subject to the limitations noted below Fluid velocity is proportional horsepower n fan eficency to motor speed over a wide range Cube law loads on ee ie wonge Rd aren of duct ff The cube law applies to applications in which fans and velocity Y sawn centrifugal pumps are used to move air water and other J fluids It derives its name from the fact that the power such loads require increases with the cube of their speed For example doubling the speed of a cube law load increases power demand by eightfold Conversely reducing its speed by 20 percent results in a roughly 50 percent drop in power requirements The range of cube law applications is vast representing more than half of motor energy use The cube Q VA f Mody fiction Lengthof factor duct of law works both ways small changes in speed can result in P __ large increases or decreases in input power This fact 2 Dg i should be considered when switching from standard Mai 7 motors to energy efficient motors because energy efficient diameter of cucc tf aa npr ar motors can have lower slip For example a standard pe
9. Heat flows by conduction through various building elements such as walls roof ceiling floor etc Heat transfer also takes place from different surfaces by convection and radiation Besides solar radiation is transmitted through transparent windows and is absorbed by the internal surfaces of the building There may be evaporation of water resulting in a cooling effect Heat is also added to the space due to the internal loads in the building which include presence of human occupants and the use of lights and equipments Source Nayak amp Prajapati 2006 Handbook On Energy Conscious Buildings Figure 37 Heat exchange processes between a building and the external environment A Q evaporation AN a radiation Se cC zJ i sly AN AA conduction Figure 38 Heat exchange processes between a human body and the indoor environment Source Nayak C Prajapati 2006 Handbook On Energy Conscious Buildings RADIATION KS EVAPORATION 1 i CONVECTION eee q XZ RADIATION g CONDUCTION Heat flow through the various components of a building s envelope involves both heat flow through solids and heat flow through layers of air The combination of heat flow by convection conduction and radiation through some typical combinations of materials is shown in Figure 39 Figure 39 Nature of heat flow through building materials and air spaces P z 1 FO EE p y y f Y Z
10. Source 15250 UK Hollow DOE 2 PROGRAM USA The thermal properties of commonly used insulating materials are shown below in Error Not a valid bookmark self reference 39 Table 8 Thermo Physical Properties of Various Thermal Insulating Materials Thermal Resistance R For the Insulating Thickness Given Per inch Poo S No Type Materials mm Thickness thickness Cr 1 k KJ kgK 1 C mK W m K W Mineral 90 2 63 ie Fiber rock Glass Fiber organic 27 7 0 96 Flexible bonded Expanded Polystyrene 34 7 1 21 Extruded 19 8 0 75 glass Loose Fill 1 09 Cellulosic Spray fiber a 23 9 20 4 Polyurethane _ 43 3 38 5 foam i wm a E Source ASHRAE Handbook 1997 Chapter 24 4 3 3 Vertical Fenestration The ECBC addresses energy losses through fenestration by specifying the following fenestration requirements minimum U Factor or Thermal Transmittance maximum Solar Heat Gain Coefficient SHGC and maximum window to wall ratio WWR of 60 for the Prescriptive Compliance Approach Vertical fenestration should meet the requirements for maximum area weighted U factor and maximum area weighted SHGC The ECBC limits the area of vertical fenestration under the prescriptive approach to a maximum of 60 of the gross wall area The U factor and SHGC requirements of the rated labeled fenestration for two WWR ranges for Code compliance are given in Table 4 3 of ECBC reproduced in Table 9
11. efficient commercial and other high rise residential buildings and their systems The commercial buildings sector represents eight percent of utility electricity consumption in India Figure 1 Consumption of Electricity by SectorFigure 1 The ECBC was developed as a first step towards producing significant savings in this sector This guide is developed to provide expanded interpretation examples and helpful tools to aid in applying ECBC compliance requirements during building design and construction Figure 1 Consumption of Electricity by Sector INDUSTRIAL DOMESTIC AGRICULTURE COMMERCIAL TRACTION MISC The ECBC is the result of extensive work by the Bureau of Energy Efficiency BEE and its working groups It is written in code enforceable language and reflects the views of the manufacturing design and construction communities as an appropriate set of minimum requirements for energy efficient building design and construction BEE reviewed building construction methods across the country and evaluated various energy efficient design build practices that could yield a reduction in building energy consumption In addition detailed life cycle cost analyses were also conducted to ensure that the ECBC requirements reflect cost effective and practical efficiency standards across different climate zones in India The result is a broad code with appropriate requirements for commercial buildings according to their site conditions and clima
12. 42 Single Glazed Unit 6mm thick coating face 2 Light Gold Dew Drop Sparkling Ice Graphite Reflectasol 0 52 Antelio Plus ST 150 0 56 Antelio Plus ST 167 0 67 Cool lite ST 136 0 44 W sqM K W Sqm 5 7 454 373 Double Glazed Unit outer 6mm with coating Face 2 12mm Air Gap inner 6mm Clear Light Gold Dew Drop Sparkling Ice Graphite Pristine White Moonshine ST 150 0 45 ST 167 0 58 ST136 0 34 PLT T 0 54 KT 155 0 36 2 8 331 2 8 359 2 8 445 2 6 281 1 77 427 1 86 290 1 8 172 Double Glazed Unit outer 6mm with coating Face 2 12mm Air Gap inner 6mm Planitherm Total Low E coating Face 3 Light Gold Dew Drop Sparkling Ice Graphite Pristine White Moonshine Reflectasol ST 150 ST 167 ST 136 PLT T KT 155 Antelio Plus Antelio Plus Cool lite Planitherm Nano 17 408 1 7 2 3 Table 12 Performance and Cost Estimates for Glazing Products Inner Glass 6mm Clear Glass Tempered 6mm Clear Glass Tempered 6mm Clear Glass Tempered 6mm Clear Glass Tempered 6mm Clear Glass Tempered 6mm Clear Glass Tempered Reflectasol Reflectasol Reflectasol Reflectasol Atanu Cool lite STB 120 Blue Tranquil F Cool lite ST 720 Cool lite ST 736 Misty Blue KT 755 Twilight Green Green Light Transmission 43 Reflectasol 6mm Low E Glass S Reflectasol Sapphire 0 21 Tempered Blue 6mm Low E Glass Royale Blue Antelio Plus ST 750 0 25 Tempered
13. 42 in or Higher opaque partition or One half the distance to an adjacent skylight or vertical glazing whichever is least as shown in the plan and section figures 7 2 1 4 Exterior Lighting Control All non exempt exterior lighting see ECBC Section 7 3 5 where lighting is required must have one of the following e Automatic switching or photocell controls provided for all exterior lighting not intended for 24 hour operation e Astronomical time switches that turn off when daylight is available Redirecting Daylight Several technologies are available or under development for redirecting daylight so that it can be more effectively used in the interior of a building Such systems use reflection refraction diffraction or non imaging optics to alter the distribution of incoming daylight These same principles are also used in light transport systems that carry and distribute daylight deep into a building s core How Light bending panels can improve daylighting Using refractive and reflective optics allows Sunlight redirecting systems work at to be distirbuteddeeper into predominantly with direct as opposed to al shaadi diffuse sunlight and they are most effective on south facing walls Options Da Light entering at steep include various types of light shelves Transmission angle of incidence is 1 t 1 k j 1 redirected to ceilling aser cut panels prismatic acrylic panels holographic optical elements and sun Light ente
14. 6mm Clear Glass Sterling Cool lite ST 120 0 22 Tempered Silver 6mm Low E Glass Reflectasol Tempered Bronze Reflectasol Bronze 0 24 6mm Low E Glass Sterling Tempered Silver Cool lite ST 120 0 18 6mm Clear Glass Tempered Turquoise Cool lite ST 436 0 25 6mm Low E Glass Tempered Blue Green Antelio Plus ST 450 0 25 6mm Clear Glass Tempered Aquamarine Cool lite ST 420 0 18 6mm Clear Glass Tempered Olive Nano KT 455 0 25 6mm Clear Glass Tropica Tempered Green Nano KT 440 0 22 6mm Low E Glass Reflectasol Tempered Green Reflectasol Green 0 19 Source St Gobain Note Price is assumed without any geometric wastage even though there could be wastage depending on the panel sizes used in the building Geometric wastage in India is assumed to be in the range of 5 15 Outer glass is assumed Heat Strengthened to avoid thermal breakage common practice in India inner glass is assumed to be tempered for safety not standard in India Price is based on what the manufacturer would invoice to the glass installer fabrication company which gets an additional margin of 5 10 from the developer builder for handling storage etc Overhangs Exception to ECBC Section 4 3 3 The SHGC requirement of a window can be affected by overhangs on a building which reduce solar gains The ECBC uses a term called a projection factor to determine how well an overhang shades the building s glazing The projection factor is calculated by measuring th
15. 7 500 9 000 Source Code No IS 13129 Part 2 1992 Table 20 Capacity Rating Test for Packaged air Conditioners Specification Cooling Capacity Maximum Power Consumption Source Code No IS 8148 2003 Table 21 Chillers Equipment Class A ala Test Standard Air Cooled Chiller lt 530 kW lt 150 tons ARI 550 590 1998 Air Cooled Chiller 2530 kW 2150 tons ARI 550 590 1998 Centrifugal Water Cooled Chiller lt 530 kW 5 80 ARI 550 590 1998 lt 150 tons Centrifugal Water Cooled Chiller 2530 and lt 1050 kW 2150 and lt 300 tons fore steed ae Centrifugal Water Cooled Chiller 2 1050 kW 2 6 30 ARI 550 590 1998 300 tons Reciprocating Compressor Water Cooled A Chiller all sizes ARI 550 590 1998 Rotary Screw and Scroll Compressor Water Cooled Chiller 2530 and lt 1050 kW 2150 and 5 lt 300 tons Rotary Screw and Scroll Compressor Water Cooled Chiller 2 1050 kW 2 300 tons These are aspirational values For mandatory values refer to ASHRAE 90 1 2004 ARI 550 590 1998 Rotary Screw and Scroll Compressor Water Cooled Chiller lt 530 kW lt 150 tons ARI 550 590 1998 i 5 2 3 Controls Controls are one of the most critical elements for efficiency of any HVAC system They give the building manager the ability to operate the system efficiently Controls determine how HVAC systems operate to meet the design goals of comfort efficiency and cost effective operation The ECBC requirements specify the
16. Fin M Vertical Fin M Factors Factors for 4 Projection for 4 Projection Factors Example 4 Prescriptive Requirements for Fenestration Location Chandigarh Climate Zone Composite Lat 30 42 N Long 76 54 E Building Type Daytime Use Building Roof Area 568 m Roof Insulation Rigid Board 1 inch R 2 1 m C W Wall Area 1130 m Wall Insulation Rigid Board 1 inch R 1 41 m C W Total Fenestration Area 508 m2 Window to Wall ratio 508 1130 45 45 East West and South facing windows are all 1 82880 m x 0 91440 m wide with a 0 45720 m overhang and represent 75 of the glazing on the building Projection Factor H V 0 45720 1 82880 0 25 M factor 0 79 From ECBC Table 4 4 Projection Factor 0 25 E W and S orientation for north latitude 15 Deg Or greater East West and South facing glazing 508 x 0 75 381 m North Facing Fenestration SHGC 0 20 U factor 3 30 East West and South Facing Fenestration Skylight Area 10 8 m Skylight to Roof Area 10 8 568 1 9 Does my building envelope comply Prescriptively with the ECBC A To utilize the prescriptive requirements of ECBC vertical fenestration is limited to 60 of the gross wall area so this building is allowed under this method ECBC Table 4 3 limits the SHGC value to a maximum of 0 20 for composite climate zone however an exception exists by use of an overhang ECBC Section 4 3 3 allows for an M Factor
17. Intense solar radiation and a generally clear sky Hot winds during the day and cool winds at night Sandy or rocky ground with little vegetation Low underground water table and few sources of surface water 40 to 45 Temperature is moderately high during day and night Very high humidity and rainfall Diffused solar radiation if cloud cover is high and intense if sky is clear Calm to very high winds from prevailing wind directions Abundant vegetation Provision for drainage of water is required 30 to 35 25 to 30 Moderate temperature Moderate humidity and rainfall Solar radiation same throughout the year and sky is generally clear High winds during summer depending on 40 to 35 20 to 25 20 to 25 30 to32 18to20 Diurnal Variation 15 to 20 Mean Relative humidity Very Low 25 40 High 70 to 90 High 60 to 85 Annual Precipitation Low lt 500 mm yr High gt 1200 mm yr High gt 1000 mm yr Sky Conditions Cloudless skies with high solar radiation causing glare Overcast cloud cover ranging between 40 and 80 causing unpleasant glare Mainly clear occasionally overcast with dense low clouds in summer Rajasthan Gujarat Western Madhya Pradesh Central Maharashtra etc Kerela Tamilnadu Costal parts of Orissa and Andhra Pradesh etc Bangalore Goa and parts of the Deccan Cold Sunny Cloudy Composite topo
18. Layer 2 L2 0 05 m of insulation k2 0 35 W m K from ECBC Appendix C R L2 k2 0 05 0 035 0 7 Km 2 W Layer 3 L3 0 15 m RCC slab Cement lime mortar and stucco ka 1 40 W m Kk from ECBC Appendix C Rs L3 k3 0 15 1 4 0 11 Km2 W Layer 4 L4 0 01 m plaster k4 0 72 W m K from ECBC Appendix C R4 L4 ky 0 01 0 72 0 014 Km2 W Roof Ro Raayert T Raayer2 z3 Raayer3 a5 Raayer4 Ri Using formula 1 4 CLVI 0 03 0 051 0 7 0 11 0 014 0 016 0 921 W m2 K Uot 1 Root 1 09 W m2 K AT 32 7 23 3 C or 305 85 296 45 K 9 4 Peat ee 2 95 2 4 3 54m 2 Amo 5 4 20 m2 It is calculated by Qeond Qwant Qroot Using formula 1 2 Qeond 1 79 54 9 4 1 09 20 9 4 908 60 204 92 1113 52 W or 1 11 kW 12 1 3 Heat Flow Through Convection Convection is the transfer of heat from one part of a fluid gas or liquid to another part at a lower temperature by mixing of fluid particles Heat transfer by convection takes place at the surfaces of walls floors and roofs Because of the temperature difference between the fluid and the contact surface there is a density variation in the fluid resulting in buoyancy This results in heat exchange between the fluid and the surface and is known as free convection However if the motion of the fluid is due to external forces such as wind it is known as forced convection These two processes could occur simultaneously
19. The existing HVAC system has sufficient capacity to serve the additional space However new ductwork and supply registers will need to be installed to serve the additional space Does the Standard apply to this construction project Ware House Office Extension A The Code applies to the 100 ft X 50 ft 30m X 15m space that is being converted from unconditioned to conditioned space However the Standard does not apply to the existing office or the existing warehouse space The new lighting system installed in the office addition must meet the requirements of Section 7 The walls that separate the office addition from the unconditioned warehouse must be insulated to the requirements of Section 4 The exterior wall and roof are exterior building envelope components and must meet the requirements for nonresidential spaces The existing HVAC system does not need to be modified but the ductwork extensions must be insulated to the requirements of Section 5 3 2 COMPLIANCE APPROACHES Prescriptive Method The ECBC is primarily a set of prescriptive requirements for building systems and components Compliance with the code can be achieved by meeting or exceeding the specific levels described for each individual element of the building systems which are covered 1 The one exception to this is for the building envelope As explained in Chapter 4 of this guide envelope system compliance can be achieved by meeting or exceeding the effici
20. These systems must also be proportionately balanced in a manner to first minimize throttling losses Further action is required if pump motors are greater than 7 5 KW 10 HP and throttling results in greater than 5 of the nameplate KW or HP draw or 2 2 KW 3 HP In these cases either the pump impeller must be trimmed or the pump speed adjusted to meet the design flow conditions 70 System Balancing Construction documents provide vital information the building owner on how to properly Operate and maintain a system that has been properly balanced Verify during final inspection that an operations manual has been passed on to the building owner and that it contains the following information at a minimum HVAC equipment capacity Equipment operation and maintenance manuals HVAC system control maintenance and calibration information including wiring diagrams schedules and control sequence descriptions A complete written narrative of how each system is intended to operate Pump heads often are oversized to assure terminal flow rates A 10 to 100 safety factor is frequently added to compensate for higher than planned head loss equipment or for unexpected piping changes But a 100 head safety factor for example increases power requirements by approximately 2 5 times depending on pump curve characteristics flat or steep Proportional balancing impeller trimming can eliminate unnecessary power consumption 5 2 6 Condensers 5
21. calculate the surface area of each exterior and semi exterior surface all areas must also be calculated separately for each orientation The equations used for calculating envelope 20 performance factor under envelope trade offs are documented in ECBC Section 12 Appendix D 3 Whole Building Performance Approach This is a compliance method that takes into consideration the overall energy performance of the proposed building design This method compares a proposed design with a standard or the base case criteria for design through the use of computer simulation Compliance is achieved is the simulation demonstrates that the proposed design is at least as energy efficient as the baseline in terms of annual energy use This approach allows great flexibility but requires considerably more effort Tradeoffs can be made between the building envelope and the lighting and or mechanical systems The base case criteria is described in detail in Appendix B of the ECBC A building complies with the whole building performance method when the estimated annual energy use of the proposed design is less than the standard design even though it may not comply with all the prescriptive requirements specified in Section 4 through 8 of ECBC 4 2 MANDATORY REQUIREMENTS Regardless of which compliance path is taken all building envelope designs must comply with several mandatory provisions These requirements relate to fenestration opaque construction a
22. energy output in the form of fluid flow exiting the pipe The bar chart compares the base case to an otherwise identical system that has a one unit reduction in pipe friction by making the pipe slightly larger smoother straighter or by using better valves This one unit savings at the downstream end of the system is compounded by efficiencies of the upstream components to yield 2 4 units of savings at the utility meter just upstream of the motor and over eight units of fuel savings at the power plant 8 2 3 Power Factor Correction Power factor correction 1s the process of adjusting the characteristics of electric loads in order to improve power factor so that it is closer to unity i e 1 In simplified electrical terminology power factor is the difference between real kW and reactive power kvar It is a measure of how effectively current is being converted into useful work output and more specifically is a good indicator of the effect of the load current on the efficiency of the supply system Power factor correction PFC may be applied either by an electrical power transmission utility to improve the stability and efficiency of the transmission network or correction may be installed by individual electrical customers to for example reduce costs charged to them by their electricity supplier while simultaneously improving energy efficiency A high power factor is generally desirable in a transmission system to reduce transmission losse
23. linkages and motors e Check maintain steam traps vacuum systems and vents in one pipe steam systems e Repair calibrate or replace controls Cooling system maintenance e Clean the surfaces on the coiling coils heat exchangers evaporators and condensing units regularly so that they are clear of obstructions e Adjust the temperature of the cold air supply from air conditioner or heat pump or the cold water supplied by the chiller a 2 to 3 F adjustment can bring a three to five percent energy savings e Test and repair leaks in equipment and refrigerant lines 19 e Upgrade inefficient chillers Fuel fired heating system maintenance possible five to 10 percent in fuel savings e Clean and adjust the boiler or furnace e Check the combustion efficiency by measuring carbon dioxide and oxygen concentrations and the temperature of stack gases make any necessary adjustments e Remove accumulated soot from boiler tubes and heat transfer surfaces e Install a fuel efficient burner Control setting maintenance 10 11 12 13 14 15 16 e Determine if the hot air or hot water supply can be lowered e Check to see if the forced air fan or water circulation pump remains on for a suitable time period after the heating unit air conditioner or chiller is turned off to distribute air remaining in the distribution ducts Implement an energy management system EMS An EMS is a system designed to optimize and ad
24. the required control device may be remotely installed if required for reasons of safety or security 7 22 MANDATORY REQUIREMENTS Mandatory requirements refer to requirements that must be met regardless of compliance approach or building type The mandatory requirements for lighting mostly relate to lighting controls and include e Automatic lighting shutoff e Space controls e Controls for daylighted areas e Exterior lighting controls e Additional independent controls There are also mandatory requirements for exit sign wattage and exterior building grounds lighting sources 7 2 1 Lighting Control Lighting controls are essential to an energy efficient commercial building They allow lighting to be turned down or completely off when it is not needed the simplest way to save energy Maximizing the use of controls involves developing a set of strategies that utilize the ECBC requirements for various devices including on off controls dimming controls and systems that combine the use of both types of equipment These controls can be quite sophisticated but in general they perform two basic functions 1 they turn lights off when not needed and 2 they modulate light output so that no more light than necessary is produced The equipment required to achieve these functions varies in complexity from simple timers to intricate electronic dimming circuits each applicable to different situations Controls include time clocks occu
25. 0 1426 1 7412 Km 2 W Minimum U Value for the composite wall 1 R 1 1 7412 0 57 W m2K NOTE Values for conductivity KX and R Values for brick wall 1920 kg m density and 13 mm lightweight aggregate gypsum plaster taken from ECBC Appendix C for thermal properties Thermal properties of 50 mm air gap are given as k 0 0352 W m K for this example For simplicity this example does not consider the resistivity of the air film at the interior and exterior surfaces of the composite wall system The R value of the inside and outside air films will also contribute to the total resistance of the wall system 4 2 3 Building Envelope Sealing Air leakage is the passage of air through a building envelope wall window joint etc Leakage to the interior is referred to as infiltration and leakage to the exterior is referred to as exfiltration Excessive air movement significantly reduces the thermal integrity and performance of the envelope and is therefore a major contributor to energy consumption in a building A tightly constructed building envelope is largely achieved through careful construction practices and attention to detail Building envelopes should be carefully designed to limit the uncontrolled entry of outdoor air into the building Air leakage introduces sensible heat into conditioned spaces In climates with moist outdoor conditions it is also a major source of latent heat Latent heat must be removed by the air condition
26. 1 10 100 Rs 100 at the end of one year Therefore the present worth of Rs 100 after one year is Rs 90 91 if the annual rate of interest is 10 PW 1 1 a 1 1 a Where PW is Present Worth a per unit inflation index annual i per unit interest rate n number of years 8 2 1 2 Measurement and Reporting of Transformer Losses To measure losses calculations must use calibrated digital meters of class 0 5 or better accuracy and be certified by the manufacturer All transformers of capacity of 500 kVA and above must be equipped with additional metering class current transformers CTs and potential transformers PTs in addition to any utility requirements so that periodic loss monitoring studies may be carried out 8 2 2 Energy Efficient Motors Electric motors are simply devices that convert electrical energy into mechanical energy Like all electro mechanical equipment motors consume some extra energy in order to make the conversion Efficiency reflects how much total energy a motor uses in relation to the rated power delivered to the shaft A motor s nameplate rating is based on output horsepower which is fixed for continuous operation at full load The amount of input power needed to produce rated horse power will vary from motor to motor with more efficient motors requiring less input wattage than less efficient models to produce the same output Electrical energy input is measured in watts while output is
27. 2 6 1 Condenser Locations A condenser is a heat exchanger designed to liquefy refrigerant vapor through heat removal The typical condensing unit houses a compressor a condenser fan motor and coils along with controls which make all the components work sequentially These units range from a half a ton for a small mini split system all the way up to several hundred tons for roof top units serving a large commercial building Without the condenser in refrigeration systems it would not be possible to reject the heat which the air handler and evaporator coil portion of the refrigeration system are responsible for absorbing The ECBC regulates condensers by specifying that they be located in as cool an environment as possible to facilitate efficient operation Condensers should be located so that the heat discharge of other adjacent equipment does not interfere with the heat sink The condenser should also not interfere with other systems installed nearby ECBC 5 2 6 1 In addition all centralized cooling water system used in high rise buildings must use soft water for the condenser and chilled water system ECBC 5 2 6 2 5 2 6 2 Treated Water for Condensers FAQs 11 Condenser What is a Chiller A chiller is essentially a packaged vapor compression cooling machine The chiller rejects heat either to condenser water in the case of a water cooled chiller or to ambient air in the case of an air cooled chiller Water cooled chillers
28. 24 Hour use buildings Hospitals Daytime use buildings Other Building Hotels Call Centers etc Types l Maximum U factor Minimum R value Maximum U Minimum R value Climate Zone of the overall of insulation factor of the of insulation assembly alone overall assembly alone W m C m C W W m C m C W NOTE The ECBC prohibits insulation from being installed directly over suspended ceilings Figure 8 Building Roofs Pre Fabricated Metal roofs showing Thermal Blocking of Purlins Membrane Steel Deck Top Chord Insulation t Bottom Chord Gypsum Board Steel Joist Roof with Insulated Cavities 2 Metal Framed Ceiling Insulation Membrane Top Chord Steel Deck Insulation Bottom Chord ___ Gypsum Board Blocking Steel Joist roof with Continuous Insulation Pa Insulation entirely above deck Insulation is installed above a a concrete b wood or c metal deck in a continuous manner a b and c are shown sequentially right to left 28 Figure 9 Typical Insulation Techniques for RCC Roof Construction A RCC Slab Insulated with Vermiculite ra Typical Roof aia ypical Roo Le i i YS Counstructions hes I Hi ai p 230 mm Brick wall 4 AA with Exterior Plaster with Insulation Vata Fillet joint along Parapet 25 mm thick China Mosaic 100mm thick BBCC 75 mm thick Vermiculite RCC Slab Floor Finishing with Vatal Fillet joint
29. C518 at a mean temperature of 24 C 75 F at the installed thickness Includes crawlspaces both ventilated and non ventilated Includes return air plenums with or without exposed roofs above 67 Table 23 Sample R Values for Duct Insulation Materials Installed R valuel ne i ne Typical Material meeting or exceeding the given R value2 1 1 2 in Mineral fiber duct liner per ASTM C 1071 Type 1 1 in Mineral fiber duct wrap per ASTM C 1290 1 in Mineral fiber duct liner per ASTM C 1071 Types I amp II 1 in Mineral fiber board per ASTM C 612 Types IA amp IB 1 in Mineral fiber duct board per UL 181 1 in Mineral fiber duct wrap per ASTM C 1290 1 in Insulated flex duct per UL 181 1 in Mineral fiber duct liner per ASTM C1071 Types I amp II 1 in Mineral fiber duct board per UL 181 1 in Mineral fiber board per ASTM C 612 Types IA amp IB 2 in 2 Ib ft3 Mineral fiber duct wrap per ASTM C 1290 2 2in 0 6 to 1 Ib ft3 Mineral fiber duct wrap per ASTM C 1290 2 2 in Insulated flex duct per UL 181 2 in Mineral fiber duct liner per ASTM C 1071 Types I amp II 2 in Mineral fiber duct board per UL 181 2 in Mineral fiber board per ASTM C 612 Types IA amp IB 3 in 34 1b ft3 Mineral fiber duct wrap insulation per ASTM C 1290 3 in Insulated flex duct per UL 181 2 1 2 in Mineral fiber board per ASTM C 612 Types IA amp IB Source ASHRAE 90 1 User Manual 2007 Table 6 D 5 2 4 2 Duct
30. Combined system consisting of Recirculation Demand and Hot Water Recovery Recitculation Demand w Pipe Insulation Combined Recirculation Demand and Pipe Insulation 6 2 5 Heat Traps system consisting of Heat traps stop hot water from rising into the distribution pipes and forming a natural circulation loop Heat traps are required in the inlet and outlet piping of all vertical pipe risers serving storage water heaters and storage tanks serving a non recirculating system These should be located as close as practical to the storage tank Heat traps may either be installed internally by the manufacturer installed as an after market add on or site fabricated Site fabricated heat traps may be constructed by creating a loop or inverted U shaped arrangement to the inlet and outlet pipes See Figure 18 and Figure 19 Figure 18 Heat Trap Heat Trap Figure 19 Heat Trap Elements Cut outs for heating coil elements ee g me d Cut outs for Electric Combustion Air 88 6 2 6 Swimming Pools Swimming pools of both the residential and commercial variety are becoming commonplace in contemporary society Observably swimming pools can be a source of considerable water loss due to evaporation Secondly the cost of the energy required to maintain the temperature of the water in the pool at a level comfortable for swimming is a strong incentive to adopt measures which promote retention of heat in the pool and retain
31. Display or accent lighting that is an essential element for the function performed in galleries museums and monuments Lighting that integral to equipment or instrumentation and is installed by its manufacturer Lighting specifically designed for medical or dental procedures and lighting integral to medical equipment Lighting integral to food warming and food preparation equipment Lighting for plant growth or maintenance Lighting spaces specifically designed for use by the visually impaired Lighting in retail display windows provided the displays are enclosed by ceiling height partitions Lighting in interior spaces that have been specifically designated as a registered interior historic landmark Lighting that is an integral part of advertising or directional signage Exit signs Lighting that is for sale or lighting educational demonstration systems Lighting for theatrical purposes including performance stage and film or video production Athletic playing areas with permanent facilities for television broadcasting Figure 204 Lighting Summary Worksheet from ECBC Appendix G 99 Lighting Summary 2007 Eneegp Conmecvetiom Buld Soda Compicce Pome 7 3 2 Building Area Method This method provides total watts per square meter for the entire building based on its type The sum of all the interior lighting power cannot exceed the total watts to be in compliance The first step is to determine the allowed power light
32. Heating Temperature Use a hot water system with a thermostat Service water heating energy use and operating costs can be reduced by simply lowering the thermostat setting on your water heater For each 5 5 C 10 F reduction in water temperature can save between 3 5 in energy costs Insulate the storage tank Install a water heater insulation blanket the higher the R value the better Use wire or twine or straps to insure that the blanket stays in place Some new high efficiency heaters should not be insulated consult the equipment manual provided by the manufacturer Gas water heaters should not be insulated on top or within about 8 of the bottom of the water tank Set an electric water heater on a rigid foam insulation board This step is most critical when the heater sits on a concrete slab but it s always a good idea Install the water heater in a heated location The colder the air surrounding the heater the more the standby loss Indoor gas heaters should be sealed combustion or fan forced draft Insulate pipes and use heat traps Insulate all exposed pipes The R value of pipe insulation is dependent on wall thickness thicker is better A 5 8 wall thickness should be considered minimum for foam insulation while 3 is the minimum for fiberglass wrap Heat trap nipples work best to eliminate convective losses from the tank into the plumbing but pipe loops also work if the drop is at least 6 What is a heat trap Heat traps a
33. India the Energy Conservation Building Code ECBC was mandated by the Energy Conservation Act of 2001 and lays down the foundation of energy policy for the buildings sector in India The code specifies the energy performance requirements for all future commercial building construction in India It is aimed at reducing building energy consumption and optimizing energy use in buildings It is planned that the code shall be mandatory once enforced for commercial buildings or building complexes It is proposed to make the ECBE mandatory for all new building that have a connected load of 500 kW or greater or a contract demand of 600 kVA or greater The code is also applicable to all buildings with a conditioned floor area of 1 000 mz 10 000 ft2 or greater Computer simulation exercises indicate that ECBC compliant buildings can use 40 to 60 less energy than similar baseline buildings It is estimated that the nationwide mandatory enforcement of the ECBC will approximately yield annual saving of 1 7 billion kWh The national code is expected to overcome market barriers which otherwise result in the under investment in building energy efficiency This is primarily due to the fact that builders have little incentive to invest in energy efficiency since they pay the up front costs and not the energy usage bills of the buildings they develop and buyers are not able to easily estimate the saving potential from investing in energy efficient construction and t
34. Install a variable air volume system VAV with variable speed drives on fan motors A VAV system is designed to deliver only the volume of air needed for conditioning the actual load 17 Upgrade to premium efficiency models when available Source North Carolina Department of Environment amp Natural Resources NCDENR 2003 Energy Efficiency in Industrial HVAC Systems 80 6 SERVICE WATER HEATING AND PUMPING 6 1 GENERAL Overview Service water heating SHW plays a small part in the energy use of a commercial building There are only several mandatory provisions that need to be checked to ensure that the water heating system meets the requirements of the ECBC 6 2 MANDATORY REQUIREMENTS The ECBC seeks to minimize Service Water Heating SWH energy usage by e Requiring partial SWH in some instances e Regulating SWH equipment efficiency e Maximizing heat recovery and minimizing electric supplemental heat sources e Requiring pipe insulation e Reducing standby losses with heat traps e Requiring swimming pool covers e Requiring compliance documentation 6 2 1 Solar Water Heating The ECBC requires that residential facilities hotels and hospitals with centralized systems have a solar water heating system for at least 1 5 of the design capacity In other words the provision of solar water heating system should be at least 20 of the total hot water requirement An exception is provided for systems that use heat recovery
35. Prepare the compliance documents All the above steps are individually discussed in detail below to understand the process of preparing models for ECBC compliance 9 2 CASE STUDY BUILDING DESCRIPTION The building consists of eight floors ground plus seven with a stilt level parking This building block on the east side is adjacent to one more building block of the same geometry See Figure 28 The building s footprint is a square shaped area of 3136 m 56 m X 56 m On the ground floor the building activity areas cover a form of 40m X 56m with the long side oriented in east west direction The built up area of the building is approx 24 000 square meters excluding the stilt level parking which caters to both the building blocks The stilt level parking area is semi exposed and is naturally ventilated Figure 28 Building Model with Stilt Level Parking Area amp Adjacent Building on the East Table 29 Ground Floor Plan of the Case Study Building a oo e a es tT ii ae y fz i fap ES ia s VAT i 4 EP pes f Cae E The ground floor contains a double height entry lobby with retail areas on either side See Figure 29 The first floor is allocated for a cafeteria See Figure 30 Second through seventh floors are typical office floor plans with office areas towards the north and south facades which are divided by central core of circulation and
36. Sealing Duct sealing is critical to avoid air leaks that prevent the HVAC system from functioning as designed and operated The ECBC currently does not provide any guidance on ductwork sealing The ASHRAE 90 1 energy code can be referred to for appropriate seal levels for all ductwork in otder to minimize energy losses from the HVAC system ASHRAE 90 1 tables 6 2 4 3 A and 6 2 4 3 B specify sealing requirements based on the duct location static pressure classification and type of the duct exhaust or return Table 24 Table 24 Ductwork Sealing Minimum Duct Seal Level Duct Type ASHRAE 90 1 Table 6 2 4 34 All transverse joints and longitudinal seams and duct wall penetrations Pressure sensitive tape shall not be ASHRAE 90 1 used as the primary sealant Table 6 2 4 3B T All transverse joints and longitudinal seams Pressure sensitive tape shall not be used as the primary sealant Transverse joints only 68 FAQs 9 Duct What are the most important elements of an efficient duct system Ducts are tubes that make up a system to distribute heated or cooled air to various rooms throughout a house There are six elements e The duct system must have a good design that is planned early in the construction process and understood by the builder framer structural engineer and designer Every fit and bend in the duct system affects the efficiency of the system The duct system must be properly installed with the cor
37. Section 7 3 3 Table 7 2 of the code individual spaces are assigned with different LPD values based on the activity within that space In this particular case study the building area method is followed in assigning the input of lighting to the model The complete building is divided into two major areas the office and the parking area separately Table 7 1 of the ECBC is followed in deciding the standard LPD values for the standard design building simulation model The LPD in the office areas is 10 8 W m2 and in the parking areas it is 3 2 W m2 for the standard design model of this proposed case study building In this case even though the parking area stilt level is unenclosed and naturally ventilated area it counts as interior area of the lighting Therefore this parking area is modeled as an unconditioned semi exterior space with only lighting No lighting controls should be modeled in the standard design model of the building 9 2 3 6 Mechanical 9 2 3 6 1 Defining the mechanical system The HVAC system of the standard design model is decided based on the following as specified in Table 10 2 of Appendix B of the code The HVAC system type and performance criteria depend on the following two categories e The occupancy type of the building residential or non residential category e The number of floor and total built up area minus the parking area of the building Depending on the above two categories the standard design buildi
38. Supply Low Voltage Sensor Line L aiia CZ Controller Luminaire 7 2 1 2 Space Control Along with controls for individual lights or sets of fixtures master controls are required for each space which can shut off all the lights within the space For example the last person leaving the office is much more likely to use a master switch than to go through the office turning off every switch Similarly a cleaning crew can easily use master switches to turn lights off at the end of a shift Each space enclosed by ceiling height partitions is required to have at least one control device to independently control the lighting within the space The device can be a switch that is activated either manually or through an automatic occupant sensor Each control device regardless of type must have the following functions a Control a maximum of 250 m2 2 500 ft2 for a space less than or equal to 1 000 m2 10 000 ft2 and a maximum of 1 000 m2 10 000 ft2 for a space greater than 1 000 m2 10 000 ft2 See Figure 21 b Be capable of overriding the required shutoff control ECBC 7 2 1 for no more than 2 hours and c Be readily accessible and located so the occupant can see the control An exception to c is provided for control devices that need to be remotely installed for reasons of safety or security However a remotely located device must have a pilot light indicator as part of or next to the control device and it must
39. Systems ASHRAE Journal 49 4 6 North Carolina Department of Environment amp Natural Resources NCDENR 2003 Energy Efficiency in Industrial HVAC Systems 7 ASHRAE 2004 handbook fundamentals American Society of Heating Refrigerating and Air conditioning Engineers Atlanta Web References an USAID ECO III Energy Conservation amp Commercialization phase 3 project ECBC Tip Sheet http eco3 org download html McGraw Hill Construction 2007 Sustainable Roofing Strategies http www construction com CE articles 0707roofing 3 asp Lawrence Berkeley National Laboratory 1997 Tips for Daylighting with Windows http windows bl gov daylighting designguide dlg pdf Bhatia Course Content PDH 149 HVAC Design Aspects Choosing A Right System Central V s Compact Systems http www pdhcenter com General Information and Energy Efficiency Tips http www esource com
40. T Temperature P Pressure Infiltration Air leaks around the frame around the sash and through gaps in movable window parts Infiltration is foiled by careful design and installation weather stripping and caulking type of sealing Convection Convection takes place in gas Pockets of high temperature low density gas rises setting up a circular movement pattern Convection occurs within multiple layer windows and on either side of window Optimally spacing gas filled gaps minimizes combined conduction and convention Radiation Radiation is the energy that passes directly through air from a warmer surface to a cooler one Radiation is controlled through low emissivity films or coatings SHGC determines the amount of radiation that can pass through glazing Conduction Conduction occurs as adjacent molecules of gas or solids pass thermal energy between them Conduction is minimized by adding layers to trap air spaces and putting low conductivity Argon or Krypton gases in those spaces Frame conductivity is reduced by using low conductivity material such as vinyl or Figure 7 Example of U Value SHGC and VT U Value 0 25 SHGC 0 39 39 of Solar Heat gain Trasmitted T 71 71 of wisible Light transmitted 4 2 2 Opaque Construction For ECBC compliance purposes it is important to determine the overall steady state rate at which heat flows through architectural envelope elements This is provided by th
41. Table 9 Vertical Fenestration U Factor and SHGC Requirements Hot and Dry Warm and Humid 40 See Appendix C of ECBC for Defaults values of Unrated Fenestration Values for unrated windows must follow the values given in Table 11 1 of Appendix C of ECBC reproduced in Table 10 Table 10 Defaults for Unrated Vertical Fenestration Overall Assembly including Sash and Frame Glazing een U Factor All All frame types All frame types Single Glazing Wood vinyl or Metal and other Energy Efficient Fenestration Products Assemblies Windows are affected by many factors which in turn affect the comfort and energy performance of buildings Understanding these factors is critical in designing buildings that meet the needs of building owners and users Once these factors are identified a designer can then apply the appropriate technology to address them A fenestration product is comprised of three areas the vision area the glazing and the opaque area ot the frame In a window glazing is generally 90 95 of the total area and therefore the most important part to address for achieving energy efficiency However the frame becomes important to optimize the overall energy efficiency of the window The energy efficiency of a fenestration product is effected by Films which are applied to improve energy efficiency Low emissivity Low E coatings for energy efficient windows Gas fill used in insulating glass units for energy efficient w
42. The units of EER are Btu Wb BER FE P where EER energy efficient ratio Btu Wh E net cooling capacity Btu h P applied energy Watts This efficiency term typically includes the energy requirement of auxiliary systems such as the indoor and outdoor fans A higher EER indicates a more efficient system Often efficiencies are measured by the Seasonal Energy Efficiency Ratio SEER which indicates how efficiently a residential central cooling system air conditioner or heat pump will operate over an entire cooling season as opposed to a single outdoor temperature As with EER a higher SEER reflects a more efficient cooling system SEER is calculated based on the total amount of cooling in Btu the system will provide over the entire season divided by the total number of watt hours it will consume Cooling eefficiencies are measured at peak load and at Integrated Part Load Value IPLV The IPLV measures the efficiency of air conditioners under a variety of conditions that is when the unit is operating at 25 50 75 and 100 of capacity and at different temperatures The concept of the most efficient chiller makes sense only in context of the facility to be cooled If a chiller operates 90 of the time at 60 load and very rarely at 90 100 load then the most efficient chiller for that application is the one with the lowest kW ton at 60 load regardless of peak load kW ton 58 The Heating Seaso
43. ballasts the wattage used must be the operating input wattage of the specified lamp ballast combination This is based on values from manufacturers catalogs or values from independent testing laboratory reports e For all other miscellaneous luminaire types the wattage used must be the specified wattage of the luminaires e For lighting tracks plug in bus ways and flexible lighting systems that allow the addition and or relocation of luminaires without altering the wiring of the system the wattage used must be the larger of either the specified wattage of the luminaires included in the system ot 135 W m 45 W ft Systems with integral overload protection such as fuses 103 or circuit breakers shall be rated at 100 of the maximum rated load of the limiting device 7 3 5 Exterior Lighting Power Lighting power limits are specified for building exterior lighting applications in ECBC Table 7 3 See Table 30 The connected lighting power for these applications must not exceed these allowed limits In addition trade offs between applications are not permitted Exemptions are allowed for the following lighting applications ONLY if they are equipped by an independent control device Specialized signal directional and marker lighting associated with transportation Lighting used to highlight features of public monuments and registered historic landmark structures or buildings Lighting that is integral to advertising signage Lig
44. be broadly categorized into five regions with distinct climates The five climate zones illustrated in the following map normally designated as hot and dry warm and humid composite temperate and cold The classification of climate for different types of buildings is an aid to the functional design of buildings Our country is zoned into several regions such that the differences of climate from region to region are capable of being reflected in building design warranting some special provision for each region The significant difference in the climatic data across these zones defines unique thermal comfort requirements for buildings located in different zones Following broadly highlights the differences in weather data in the five climate zones and Table 36 below provides a list of major cities in India with respect to their climate zones These differences in the weather profile translate into unique requirements for building thermal comfort and architectural responses for the different climate zones See in Figure36 Section 4 Figure 36 Climate Zone Map LEGENDS MM boron E P WAARM HUMID A 0 COMPOSITE i i CS TesPerare i he el E coun Source National Building Code 2005 Part 8 Fig 2 CXLVI Table 35 Classifications of Different Climate Zones in India Hot amp Dry Mean Temperature C Winter night Low o 25 to 30 Description High temperature Low humidity and rainfall
45. better match motor to load Potential for improved efficiency Reduced Energy use in cube law roads Capital cost savings If rewinding use high quality practice core loss Minimize core damage and efficiency loss testing Cooler operation Good motor system maintenance Monitor vibrant and noise cleaning measure and mitigate resistive Longer motor life hot spots resistive and inductive imbalances and Higher efficiency excess capacitance Improved starting torque Consider advantage motor types Switched reluctance Often smaller size permanent magnet Improved variable speed control High efficiency over wide range of speed and load FAQs 17 Motor What is an energy efficient motor Motor efficiency is the ratio of mechanical power output to the electrical power input usually expressed as a percentage Energy efficient motors use less energy Because they are manufactured with higher quality materials and techniques they usually have higher service factors and bearing lives less waste heat output and less vibration all of which increase reliability This is often reflected by longer manufacturer s warranties A 30 hp motor is in of replacement or rewinding What would be the best course of action In general it is best to replace a motor if it is less than 40 hp the cost of the rewind exceeds 65 percent of the price of a new motor or the motor was rewound prior to 1980 A motor runs at 215 of the calculate
46. buildings The envelope and its components especially windows and skylights have a significant effect on the heating and cooling needs which drive a building s energy use The envelope design must take into consideration both external and internal loads as well as daylighting benefits External loads include solar gains conduction losses across envelope surfaces and air infiltration while internal loads include heat gain from lights equipment and people General Concepts Building Loads External and Internal 14 External loads include solar gains through windows conduction losses due to temperature differences across envelope surfaces and air leakage or infiltration See Figure 4 Exterior loads are dynamic They change as outdoor temperatures and environmental conditions change as the sun moves through the sky and as wind changes speed and direction The building s envelope design directly affects the magnitude and time pattern of external loads To maintain thermal comfort and minimize cooling heating loads the building envelope needs to regulate and optimize heat transfer through roof walls Figure 4 External Load windows doors other openings and cracks Solar gains can be controlled by correctly orienting and shading windows and by glazing specifications that limit solar gain while Conduction Convection P o l l 8 transmitting visible light conduction loads can be reduced by effective insulation and infiltrat
47. by better mechanical and ventilation systems In many existing buildings envelope upgrades are often necessary to improve comfort and energy efficiency through improvements such as reducing envelope leakage The best HVAC design considers all the interrelated building systems while addressing indoor air quality thermal comfort energy consumption and environmental benefit Optimizing both the design and the benefits requires that the architect and mechanical system designer address these issues early in the schematic design phase and continually revise subsequent decisions throughout the remaining design process It is also essential that a process is implemented to monitor proper installation and operations of the HVAC system throughout construction An effective routine preventative maintenance program should also be delivered to the owner at the building s completion to ensure that the building operator maintains temperature settings and schedules that deliver energy savings and comfort The tip box below presents six key steps for the design of a high performance and energy efficient HVAC system 1 ADOPT AN INTEGRATED BUILDING Integrate the architectural and engineering concerns Besien sorunon aa onin he dezin protes on 2 ESTABLISH DESIGN CONDITIONS Optimize system design based on differences in the activity levels ventilation amp thermal comfort requirements internal loads and energy performance criteria RIGHT SIZE
48. capacity Hour per square foot per degree Fahrenheit per British thermal unit Hour per square meter per degree Celsius per Watt Horsepower Heating seasonal performance factor Heating Ventilation and Air Conditioning Inch pound Inch IPLV ISHRAE kVA kW kWh LE lin lin ft lin m Im LPD NAECA PF PTAC SC SHGC SL VAV VLT W ft2 W m W m2 C W m W m C W m2 C Integrated part load value Indian Society of Heating Refrigeration and Air conditioning Engineers Kalovolt ampere kilowatt kilowatt hour Lighting efficacy Linear Linear foot Linear meter Lumen Lighting Power Density Meter Millimeter National Appliance Energy Conservation Act Projection factor Packaged terminal air conditioner R value thermal resistance Shading Coefficient Solar heat gain coefficient Standby loss Variable air volume Visible light transmission Watt Watts per square feet Watts per square meter Watts per square meter per degree Celsius Watts per hour per square meter Watts per lineal meter per degree Celsius Watts per hour per square meter per degree Celsius Watthour CXLIV 1 CLIMATE ZONE MAP OF INDIA 11 1 CLIMATE ZONES The first step in following the ECBC is determining the appropriate climate zone of the building site which will dictate the specific requirements for design and construction of the building systems and components India possesses a large variety of climates which can
49. code have been designed to be flexible enough to allow architects and engineer the ability to comply with the code and meet the specific needs of their projects according to the climate conditions of the site 3 1 COMPLIANCE REQUIREMENTS 3 1 1 Mandatory Requirements Mandatory requirements must be followed in every building regardless of compliance approach Apart from meeting mandatory requirements inspection at site coupled with proper installation technique is essential for meeting the intent of the building energy code Compliance with the requirements of this energy code shall be mandatory for all applicable buildings discussed in Section 2 3 1 2 New Buildings The ECBC compliance procedure requires the building to fulfill a set of mandatory provisions related to energy use as well as demonstrate compliance with the specified minimum energy consumption guidelines stipulated for the different building components The submittal documents include the building plans and specifications that show all pertinent data and features of the building equipment and systems in sufficient detail to permit the authorized personnel jurisdiction to verify that the building is compliant The authority having jurisdiction may require supplemental information necessary to verify compliance with this code such as calculations worksheets compliance forms manufacturet s literature or other data To maintain flexibility for the design and construction
50. continuously 8 760 hours per year Using simple or complex controls duty factors can often be reduced to about 3 000 hours per year or less by limiting fan operation to occupied periods The mechanical efficiency of the fan and its drive system can typically be raised from the 40 to 60 range to the mid 80 range Design options for improving air distribution efficiency include e Variable air volume VAV systems e VAV diffusers e Low pressure drop duct design 59 e Low face velocity air handlers e Fan sizing and variable frequency drive VFD motors e Displacement ventilation systems Energy Efficient HVAC Design As the climate map of India shows Appendix E ECBC most of India falls mainly under three climatic zones hot dry warm humid and composite requiring the cooling of buildings for almost 6 8 months to provide thermal comfort to the occupants All of this comes with significant energy consumption and costs Both need to be addressed while designing any building The overall capacity system type and energy performance of HVAC systems depend to a large extend on the overall cooling load of the building The first step towards a Whole Building Design approach for creating an energy efficient system would be to reduce the cooling load by controlling unwanted heat gain in the building As shown in Figure 14 external heat gains can be avoided with architectural form light colored building surfaces vegetation
51. energy infrastructure the building industry and our urban growth trends increase environmental degradation greenhouse gasses and overall ecological footprints of our towns and cities Mandating the energy performance of the building envelope lighting heating ventilation and air conditioning HVAC and other building systems through codes can standards can offer national governments many important benefits By 1999 twenty two countries had mandatory building energy efficiency standards three had voluntary standards and many others had proposed or were considering standards These existing building energy efficiency standards are estimated to yield a wide range of energy environmental and economic benefits For example According to the U S Department of Energy DOB if all 50 U S states adopted and fully implemented American Society of Heating Refrigerating and Air Conditioning Engineers ASHRAE Standard 90 1 1999 a model energy code for commercial buildings then building owners and tenants would lower their utility bills by 110 million the first year and save 5 7 billion over 10 years The country would save 16 trillion British thermal units Btu of energy that first year and almost 800 trillion Btu cumulatively over 10 years fi Mandatory fj Proposed or Considering P Voluntary L None Status of Building Energy Efficiency Standards Worldwide Source Lawrence Berkeley Lab hitp eetd lbl gov EA ecsw ecsw html In
52. for at least 1 5 or 20 of the design capacity Heat recovery water heating is the heating of domestic hot water with the waste heat from the air conditioning system This heat is rejected from the air conditioner s condenser to the atmosphere By recovering this wasted heat and utilizing it to heat water it is possible to substantially reduce water heating costs There are two types of solar water heaters Passive heaters collect and store solar thermal energy for domestic water heating applications and do not require electrical energy in put for recirculating water through a solar collector Active heaters collect and store solar thermal energy for domestic water heating applications and require electrical energy input for operation of pumps or other components Figure 17 below shows examples of solar water heating systems 81 Figure 17 Examples of Solar Water Heating Systems Active Closed Loop Solar Water Heater Hot Water Collector M Cold Water Supply Antifreeze fluid in collector loop Only Solar Storage backup Water Heater Double walled Fump Heat Exchanger Spigot Drain valve ffor cold Climates Solar Storage L7 backup water Bypass Valves a 1 _ Heater Cold Water H Supply S PROGRESS TUBE Bowler Drain Bronze Tempering Valve Pressure Relief Valwe Supply Shut Off Vale Thupa DIRECT SYSTEM 6 2 2 Equipment Efficiency The mandatory requirements for
53. for unconditioned storage spaces ot warehouses or equipment and portions of building systems that use energy primarily for manufacturing processes ECBC also DOES NOT apply to replacement glass of an existing sash and frame modifications to building cavities insulated to full depth and modifications to wall and floors with cavities and where no new cavities are created ECBC shall not be used to circumvent any safety health or environmental requirements If there is a conflict between the requirements of this code then the safety health or environmental codes shall take precedence SAFETY HEALTH AND ENVIRONMENTAL CODES TAKE PRECEDENCE Where this code is found to conflict with safety health or environmental codes the safety health or environmental codes shall take precedence 2 4 REFERENCE STANDARDS National Building Code 2005 NBC 2005 has been considered as the reference document standard for lighting comfort levels HVAC comfort levels natural ventilation pump and motor efficiencies transformer efficiencies and any other building materials and system performance criteria ECBC is presently for adoption on a voluntary basis but may become mandatory with notification by the central and state government in accordance with the Energy Conservation Act 2001 3 ADMINISTRATION AND ENFORCEMENT he ECBC includes requirements that address energy saving opportunities in buildings The energy consumption requirements of the
54. heat loss Heated pools can be a source of significant heat and humidity gain in a building The ECBC requires that all interior or exterior heated pools shall be provided with a vapor retardant pool cover on or at the water sutface Pools heated to more than 32 C 90 F shall have a pool cover with a minimum insulation value of R 2 1 R 12 An exception is provided for pools deriving over 60 of their energy from site recovered energy or solar energy source 6 2 7 Compliance Documentation When submitting building applications for approval they must include detailed calculations that demonstrate 1 the SHW system is designed to ensure that at least 20 of the heating requirement is met from solar heat heat recovery 2 not more than 80 of the heat is met from electrical heating and 3 where gas is available not more than 20 of the heat shall be met from electrical heating 89 7 LIGHTING 7 1 GENERAL Overview Electricity for lighting is the largest energy end use in commercial buildings typically accounting for 20 40 percent of the total energy consumption Lighting is also a significant power demand on the electric grid and contributes significantly to the amount of energy needed for cooling Efficient lighting systems can help to reduce total energy use and save money protect precious natural resources and help to reduce the overall amount of greenhouse gases produced by the commercial building sector An energy efficient l
55. high performance glazing etc Internal heat gains can be reduced by using more efficient building equipment such as lights computers printers copiers servers and direct venting of spot heat sources Figure 14 Cooling Load Reduction Measures Light cotered roof ooatiogs reflect Plan for i make Conky cquipnsemi and solar radiation and reda modihed air ance intemal and conduetio potenlial tiere aad f deciin ata It at alae Insaaahinng dhe reaf Poales doene real connductean 2 the inde of the sulidieg Structar oah angs ghcubehers reduce solar sumomarciqucers red Ouvers and salar screens hack slat radiation Spectrally zo lorate piazings let lighet im but keep heat out Window kirats sechece voller quate wither sacl icing daylight or Cre Source E Source Cooling Atlas Huge savings are available from reducing the velocity pressure and friction losses in ducts and piping Light commercial buildings typically use constant air volume rooftop HVAC units applying the same ductwork and installation techniques found in residential systems They are generally un engineered systems leading to short cuts in construction practices and or the use of lower grade materials to deliver a project within budget In the case of ductwork this shows up as sloppy connections inexpensive leaky diffusers and low grade duct tapes With respect to the HVAC equipment this leads to installations and service techniques that produce degr
56. into two categories single ply materials and coatings Single ply materials are large sheets of pre made roofing that are mechanically fastened over the existing roof and sealed at the seams Coatings are applied using rollers sprays or brushes over an existing clean leak free roof surface Products for sloped roofs are currently available in clay or concrete tiles These products stay cooler by the use of special pigments that reflect the sun s infrared heat How cool is a Cool Roof During the summer a typical dark roof has a surface temperature of 65 to 88 C at peak while cool roofs peak surface temperature remains between 38 C to 40 C Do Cool Roofs cost more than conventional roofs Research shows that the cost of a cool roof compared to a traditional roof can be the same or slightly higher per square foot for the cool roof One analysis showed cool roofs to be cost effective over the life cycle of the roofing material Cool protective coatings can be reapplied repeatedly every 10 to 15 years and reduce if not eliminate the need for expensive roof tear offs Combining these maintenance savings with an average 20 percent savings on ait conditioning costs make cool roofing a better bargain over the long term Technical Tips for Cool Roofs Use of solar reflective urban surfaces and planting of urban trees are inexpensive measures that can reduce summertime temperatures Image Source McGraw_Hill Construction 2007 Sust
57. light reflecting surface using this surface to bounce daylight deep into the room can be highly effective Both of these strategies are utilized in light shelf designs Figure 12 Light Shelf Examples and Design Tips 49 A ry Projecting light Shelf fise i w block sunlight and shade window underneath Lower Window may allow sunlight penctratinn below eye level Light Shelf Sloped downward to provide shading but dose not reflect light into building Source Steve Meder Course Documents ARCH 316 School of Architecture University of Hawaii at Manoa 4 3 3 1 Minimum Visible Transmission of Glazing for Vertical Fenestration The ECBC encourages the use of daylighting features in buildings by defining the minimum Visual Light Transmittance VLT levels for vertical fenestration The prescriptive requirements place minimum limits on VLT with respect to variation in WWR Determine the window to wall ratio and meet the corresponding VLT minimum in ECBC Table 4 5 to implement allowable daylighting strategies Vertical fenestration products must meet the minimum VLT defined as a function of Window Wall Ratio WWR where Effective Aperture gt 0 1 equal to or greater than the Minimum VLT requirements of ECBC Table 4 5 reproduced below in Error Reference source not found Table 14 Minimum VLT Requirements Window Wall Ratio Minimum VLT 50 Effective Aperture Effective Aperture One method of asses
58. or more sections A packaged boiler includes factory built boilers manufactured as a unit or system disassembled for shipment and reassembled at the site Building a structure wholly or partially enclosed within exterior walls or within exterior and party walls and a roof affording shelter to persons animals or property Building existing a building or portion thereof that was previously occupied or approved for occupancy by the authority having jurisdiction Building complex a group of buildings in a contiguous area under single ownership Building entrance any doorway set of doors turnstiles or other form of portal that is ordinarily used to gain access to the building by its users and occupants Building envelope the exterior plus the semi exterior portions of a building For the purposes of determining building envelope requirements the classifications are defined as follows Building envelope exterior the elements of a building that separate conditioned spaces from the exterior Building envelope semi exterior the elements of a building that separate conditioned space from unconditioned space or that enclose semi heated spaces through which thermal energy may be transferred to or from the exterior or to or from unconditioned spaces or to or from conditioned spaces Building exit any doorway set of doors or other form of portal that is ordinarily used only for emergency egress Of convenience exit Building grounds l
59. or they can be packaged units which are factory built systems disassembled for shipment and reassembled at the site The heated water may serve preheat coils in air handling units reheat coils and local radiators Systems that circulate water or a fluid are called hydronic systems Additional uses for the heating water are for heating of service water and other process needs depending on the building type Some central systems have steam boilers rather than hot water boilers because of the need for steam for conditioning needs humidifiers in air handling units or process needs sterilizers in hospitals direct injection heating in laundries and dishwashers etc The remaining heating systems include heat pumps and space heaters that heat directly and require little or no distribution HVAC Equipment Efficiency Measurements The cooling efficiency for air conditioners is rated as the Cooling Load in kW ton for larger machines and Energy Efficiency Ratio EER or Coefficient of Performance 57 COP is rated for smaller machines Similarly in heating modes the Heating Season Performance Factor HSPF and the Annual Fuel Utilization Efficiency AFUE measures the efficiencies for heat pumps and gas furnaces boilets respectively Cooling Load is defined as the ratio of energy consumption in W to the rate of heat removal in tons at the rated condition The lower the amp W ton the more efficient is the system The
60. process is called loss evaluation 106 The concept of evaluation can be applied to transformers with the assumptions that the annual losses and the load level remain steady at an equivalent annual value the tariff is constant and the rates of inflation and interest are constant These assumptions have obvious limitations but the Total Lost Energy concept is a widely used method for evaluation The total losses for dry type transformers should conform to the draft standard of Indian Standard IS 2026 Part 11 2007 shown in Table 8 1 Total losses for oil filled transformers should conform to Table 8 2 as specified in Central Electricity Authority norms Transformers selection must account for minimal total initial cost in addition to the present value of the operational costs of estimated loads for it life span Calculating Present Value The cost of a transformer includes the initial investment and ongoing payment of energy charges during a given period The Total Lost Energy Cost can be calculated by adding the present worth of future energy charges This accounts for future energy expenses and shows a better measure of comparing equipment with higher first cost but a higher efficiency and thus lower running charges Present value is also known as Present Worth The deferred monetary gains expenses are expressed in terms of their present worth PW Example If Rs 90 91 is invested at an annual interest of 10 it will yield 90 91x
61. reflectance and initial emittance levels are specified ECBC 4 3 1 1 Maximum U factors and SHGCs are provided for all vertical fenestration based on climate however there are modifications allowed to the SHGC limits when using overhangs or fins and in the case of windows located over 2 2 meters from the floor ECBC 4 3 3 Vertical fenestration is also required to meet minimum levels of visual light transmittance VLT to facilitate use of daylighting ECBC 4 3 3 1 Similarly skylights have U factor and SHGC maximum levels determined by ECBC and are also limited to 5 percent of the gross roof area ECBC 4 3 4 4 3 1 Roofs Exterior roofs or ceilings See Table 4 can meet the prescriptive requirements in one of two ways e Use the required R value of the insulation this R value does not apply to building materials or air film It should be referred exclusively for insulation or e Use a roof assembly U factor that meets the maximum U factor criterion for thermal performance see Table 4 3 1 The U factor takes into account all elements or layers in the construction assembly including the sheathing interior finishes and air gaps as well as exterior and interior air films ECBC Table 4 1 reproduced below in e Table 4 provides the maximum limits of the U factor and minimum limits of R Values for 24 hrs use buildings and daytime use buildings Table 4 Roof Assembly U Factor and Insulation R Value Requirements 26
62. resistance rn2 K Outer surface Convective heat transter coefficient W mz K 15 870 Radiative heat transfer coefficient pa mz E a A Surface resistance m ki 0 040 No Bridging U Value surface to surbace W rn2 F 2 40 Rale r2 Ky 0 572 U Yalue vw m2 F 1 748 with Bridging BS EN 150 6946 Upper resistance lint mz K Lower resistance lint m ki U Value surface to surbace M mz E AValue ri B U Value fi sm2 F The simulation program used will have libraries of many common building materials As shown in the above figure all the properties of each material are considered in calculating the final U value of the total composition The software also includes the air film resistance in calculating the U value Figure 34 Glazing Spread Distribution on the Walls in the Proposed Case yi T ee tll wt sit m gt piil T 1 m yiti T m T wl ipil piit While modeling the facades of the building the total window area on each orientation of the building N S E or W can be considered as one single data input as opposed to inputting separate windows as unique data entries in the simulation model However if the building uses any daylight controls or there are differences in shading devices the windows need to be modeled separately as individualized and unique building elements In this case study windows are spread on the external wall in the existing ratios as calculated from the proposed design See
63. result in savings around the clock every day of the year 8 2 1 1 Maximum Allowable Power Transformer Losses The ECBC lists ratings for various transform sizes of dry type and oil filled transformers and their associated losses at 50 and full loading Table 31Table and Table 32 The proper rating and design selected must satisfy the minimum acceptable efficiency 105 Table 31 ECBC Table 8 1 Dry Type Transformers Rating Max Losses at Max Losses at Total losses at Total losses at KVA 50 loading kW 100 loading 50 loading kW rated load kW kW i Table 32 ECBC Table 8 2 Oil Filled Transformers Rating Max Losses at Max Losses at Total losses at Total losses at KVA 50 loading kW 100 loading 50 loading kW rated load kW kW w feo o o pe o e In the building industry it is very common that transformers are part of a turn key project The contractor is often interested in a transformer with a low purchase price However the user owner of the transformer wants the cheapest transformer i e with the lowest total owning cost which complies with the requirements for a given application Losses installation maintenance repair and decommissioning costs are seldom taken into account by the contractor when choosing between transformers The ECBC requires only that the Tota Lost Energy Cost be considered when transformers are selected When comparing transformers with respect to energy losses the
64. roof slab insulated with 5 00 cm thick expanded polystyrene density of 24 kg m and finished with 4 00 cm thick brick tiles density of 1760 kg m3 on the top and 1 00 cm thick cement plaster on the bottom as shown in figure below TILE 40MM INSULATION 50MM R C C SLAB 150MM PLASTER 10MM K If the room is maintained at 23 3 C by an air conditioner what is the total heat cooling load on the HVAC system for the month of May The daily average outside temperature in May is 32 7 C SOLUTION 1 Cooling Load on the HVAC system is equal to the total conduction load into the room through the four walls 2 walls with surface of 15 m and 2 walls with surface area of 12 m and the roof surface area 20m2 R thermal resistance of inside air surface film still air 0 16 K m 2 W Ro thermal resistance of outside air surface film 24 km h wind 0 03 K m2 W Ri and Ro values are taken from Chapter 25 Table 1 Surface Conductances and Resistances for Air of the ASHRAE Fundamentals First we need to estimate U values for the building envelope For the walls Ryan 0 37 K m W for the concrete block wall From ECBC Appendix C Ryall_tor Ro Rwan Ri Using formula 1 4 0 03 0 37 0 16 0 56 K m 2 W Uwal tot 1 Revat_tor 1 79 W m K The roof is comprised of 4 layers Layer 1 L1 0 04 m of brick tile ki 0 79W mkK Range 0 71 0 85 from ECBC Appendix C Ry Li ki 0 047 0 79 0 051 Km 2 W
65. than one half glass are considered fenestration For the purposes of determining building envelope requirements the classifications are defined as follows Door non swinging roll up sliding and all other doors that are not swinging doors Door swinging all operable opaque panels with hinges on one side and opaque revolving doors Door area total area of the door measured using the rough opening and including the door slab and the frame Dwelling unit a single unit providing complete independent living facilities for one or more persons including permanent provisions for living sleeping eating coking and sanitation Economizer ait a duct and damper arrangement and automatic control system that together allow a cooling system to supply outdoor air to reduce or eliminate the need for mechanical cooling during mild or cold weather Economizer water a system by which the supply air of a cooling system is cooled indirectly with water that is itself cooled by heat or mass transfer to the environment without the use of mechanical cooling Effective aperture Visible Light Transmittance x Window to wall Ratio EA VLT x WWR Effective aperture horizontal fenestration a measure of the amount of daylight that enters a space through horizontal fenestration skylights It is the ratio of the skylight area times the visible light transmission divided by the gross roof area above the daylighted area See also daylighted area Effective a
66. the ECBC include minimum efficiencies presented in available Indian Standards for the various water heating equipment such as electric and gas heaters instantaneous heaters boilers and pool heaters These efficiency requirements are presented in available Indian Standards as follows Table 25 Conditions for Thermal Performance Test of SDHW System Clause 9 5 2 Incident Radiation Radiation Incident Time h Non Solar a ee 7 oy Load liters KJ mh m h j l 0800 0900 0 y G OT 0900 1000 0o 1234 56 1000 1100 0 1624 576 30 30 1100 1200 ot 884 576 S 1200 1300 ot 964 576 A y N 1300 1400 ot 884 576 S 1400 1500 O0 1624 576 8 1500 1600 0 1224 576 O o a 1600 1700 ot HH 1700 1800 o T e S S ON 1800 1900 S o S e S S oN 1900 2000 e e S oN a ll Source IS 13129 Solar Heating Dr Water Heating Systems Part 1 performance Rating oer using Indoor Test Methods Table 25 Standardized Conditions for analysis of Long Term Energy Savings Clause 6 7 Climatel Climate 2 Fraction of Months se g MJ m d Te C g al a d T C normal loa o Ja 4 2 2 O EE E E E E E a 08 Source a is 13129 Par 2 7 aE Solar ae Domestic ve TT Systems Part 2 Procedure for system performance characterization and yearly performance prediction e Reference IS 15558 gas instantaneous water heaters must meet the performance minimum efficie
67. the algebra becomes complicated Besides the effects of a variation of outside air temperature and solar radiation with time b shading by neighbouring objects c self shading d thermal capacity of the building i e the ability of building materials to store heat during daytime and release it back to the environment later add to the complexity of the calculations Consequently one resorts to computer based tools known as building simulation tools A number of such tools are now available to do quick and accurate assessment of a building s thermal and daylighting performance These tools can estimate the performances of different designs of the building for a given environmental condition From these results a designer can choose the design that consumes minimum energy Thermal calculations also help to select appropriate retrofits for existing buildings from the viewpoint of energy conservation Thus by integrating the simulation of thermal performance of a building with its architectural design one can achieve an energy efficient building A number of tools are available for simulating the thermal performance of buildings they address different needs For example an architect s office requires a tool that is quick and gets well integrated into the design process On the other hand an HVAC engineer would look for a tool that would accurately predict the energy a building would consume for optimum sizing of the air conditioning system
68. the cooling needs of the building Appendix E of ECBC classifies GandhiNagar as hot and dry climate All the characteristics of the building in the standard design model are considered as per its climate classification from the respective tables of building envelope A review of the detailed input of both the standard design model and the proposed case model show that the proposed design model does not meet the U factor standard requirement of the wall as specified in the prescriptive table of the code Since the frame of the window is unlabeled the resultant U factor of the complete window assembly is also high when compared with the U factor of the standard design simulation model However the internal lighting load is 20 less than the standard in the proposed design model Also a low SHGC glass is used in the proposed building compared to the standard specified by ECBC 9 2 1 Step I Confirmation from the Local authorities Before starting to develop the building simulation models to show ECBC compliance it is advisable to meet the local authorities to confirm whether the building comes under the scope of ECBC and whether it is practically possible for the building to comply with ECBC standard design model in terms of its energy consumption The following are some of the issues which are to be confirmed by the local authorities e Is ECBC applicable to the building e Can this building apply for ECBC compliance and what are the submittal requi
69. the five climatic regions of India and the second was to support Maharashtra Energy Development Agency in developing strategies for energy conservation and implementation of selected programs Since November 2006 International Resources Group IRG with support from its partners IRG Systems South Asia Alliance to Save Energy and DSCL Energy Services has been implementing the ECO III Project by working closely with BEE Gujarat Energy Development Agency Punjab Energy Development Agency international experts academic institutions and private sector companies The major objective of the ongoing ECO III Project is to assist BEE in the implementation of the Energy Conservation Act The focus areas include 1 development of the Energy Conservation Action Plan at the state level 2 implementation of the Energy Conservation Building Code 3 improvement of energy efficiency in existing buildings and municipalities 4 inclusion of energy efficiency subjects in architectural curriculum and 5 enhancement of energy efficiency in small and medium enterprises FOREWORD To be Added March 2009 Ajay Mathur ACKNOWLEDGEMENTS To be Added March 2009 Satish Kumar PREFACE The heating cooling ventilation and lighting requirements in a commercial building account for 30 to 40 of primary energy worldwide India s building sector is growing at a rapid pace and is the third largest consumer of energy after the industrial and agricultu
70. the molecules of a material at a higher temperature to the molecules of another material which is at a lower temperature Heat can be conducted through solids liquids and gases At the microscopic level conduction in a solid takes place due to the vibration of atoms and molecules In gases conduction takes place due to random motion of atoms and molecules Some materials conduct more rapidly than others The basic equation of heat conduction is Qeond quantity of heat flow W k thermal conductivity of the material W m K A area m L thickness m Th temperature of the hot surface K T temperature of the cold surface K Equation 1 1 shows that for a given temperature difference the higher the thermal conductivity of a material of fixed thickness and cross sectional area the greater is the quantity of heat transferred The thermal conductivity and the thickness of the materials in equation 1 1 determine the overall R value U value of the building envelope component Similarly the Th and T can be considered as the interior and exterior temperatures of the building Thus the rate of heat conduction Qcona through any element such as roof wall ot floor Equation 1 1 can also be written as Ood AUT a AT U TA Torr 12 Where A surface area m7 U thermal transmittance W m K k L AT temperature difference between inside and outside air IX The U Value is the thermal conductance of the building
71. the risk of contamination In health care facilities or service water systems maintained below 85 60 C periodic flushing of the fixtures with high temperature water or other biological controls may be appropriate Table 27 Service Water Temperature Use Temperature F Hand Washing 115 Showers and tubs 110 Therapeutic baths 95 Commercial and institutional laundry lt 180 Residential dishwashing and laundry 140 Surgical scrubbing 110 gt 150 wash Rack Type l l 180 to 195 final rinse l gt 160 wash Single tank conveyor type 180 to 195 final rinse gt 150 wash Multiple tank conveyor type gt 160 pumped rinse 180 to 195 final rinse 140 wash gt 75 rinse Chemical sanitizing type 6 2 3 Supplementary Water Heating System Supplemental Water Heating System shall be designed to maximize efficiency and shall incorporate and prioritize the following design features as shown 1 Maximum heat recovery from hot discharge system like condensers of air conditioning units 2 Use of gas fired heaters wherever gas is available 3 Electric heater as last resort 6 2 4 Piping Insulation To minimize standby losses the ECBC requires that pipelines for the entire hot water system including the storage tanks shall be insulated conforming to the relevant IS standards on materials and applications Piping insulation must comply with ECBC Section 5 2 4 1 FAQs 14 Demand Water Heaters What is a demand water heate
72. the total watts of input power expressed in lumens per watt The resulting value is lumens per watt sometimes referred to as LPW Lamp efficacy values ate based exclusively on the lamp s performance and do not include ballast losses Lamp system efficacy values measures the performance of the lamp and ballast combination and this includes the ballast losses Relative efficacy of major light sources Lumens Watt Standard incandescent C Tungsten halegen ee Halogen infrared refiex ting Meragy vapor Compact fluorescent 5 120 W Flucescent fiie and Hube met Ls 20 a aa 7e 190 120 140 Efficacy including ballasts umens per walt What is a luminaire A luminaire is the lighting industry s term for light fixture A luminaire consists of the housing power supply ballast lamp reflector and in some cases a lens A lamp is the lighting industry s term for a light bulb Luminaires can be designed to be recessed into the ceiling suspended by a rod or chain or surface mounted on the wall or ceiling How do you identify a high efficacy luminaire A high efficacy luminaire is one that contains only high efficacy lamps and does not contain a conventional medium screw based socket Typically high efficacy luminaires contain pin based sockets like compact or linear fluorescent lamp sockets though other types such as screw sockets specifically rated for high intensity discharge lamps like metal halide lamps may a
73. yet designed As pet ECBC the classifications of spaces are as follows for the purpose of determining building envelope requirements a Conditioned space a cooled space heated space or directly conditioned space b Semi heated space an enclosed space within a building that is heated by a heating system whose output capacity is greater or equal to 10 7 W m 3 4 Btu h ft of floor area but is not a conditioned space c An enclosed space within a building that is not conditioned space or a semi heated space Crawlspaces attics and parking garages with natural or mechanical ventilation are not considered enclosed spaces 9 2 3 2 Walls The proposed building in Gandhinagar has two main types of walls the external walls and the internal partitions See Figure 31 The walls of the building should be categorized based on their position within the building Appendix A of the code under the subhead of Walls deals with the definitions of various kinds of walls in a building The U CXX value of the walls should meet with requirements mentioned in Table 10 1 4 of Appendix B and in the Section 4 3 2 Table 4 2 Figure 26 Category of Walls in a Typical Floor Plan in the Case Study Building Interior walls Exterior walls 9 2 3 3 Roof For the standard design building model the roof requirements are as specified in Table 10 1 4 of Appendix B of the code This table further refers to Section 4 3 1 Table 4 1 where the U value
74. 1 Building Envelope All the walls which are within 45 degrees of each other can be combined into a single wall having the same orientation All the thermal properties of the building envelope need to be correctly defined in the model Definitions of walls must include thermal mass specific heat and density as well as resistance to heat flow U factor or R value Wall assemblies in the simulation model have to be built up out of a library of physical properties for different building materials See Figure 32 Figure 32 Wall Cross Section of the Case Study Building as Shown in the Software Cross Section Outer surface The external wall section of this building proposed in Gujarat is a combination of 230mm brick with plaster on either side On the external surface of the wall granite stone cladding is done in most of the areas of the facades If the material properties and R values are provided by the manufacturer they must be combined together to calculate the complete U value of the construction In this case study the specified materials are available in the simulation software library which are combined to form the required construction The resultant U value of the wall is 1 75 W m2K See Figure 33 Figure 33 U Value of the External Wall of the Case Study Building as Calculated by the Energy Simulation Tool Inner surface Convective heat transfer coefficient WW me F Radiative heat transfer coefticient p mz F Surface
75. AC systems These differences can provide as guidelines for choosing the appropriate system type for the building 55 Table 16 Overview of local and central HVAC systems ee CENTRAL SYSTEMS LOCAL SYSTEMS Building Space Requirements Aesthetics Controls Air Quality Efficiency Will require separate building space to house the chillers boilers pumps AHU s distribution networks and control panels In addition space is required outdoors for condensing unit for air cooled machines and cooling tower for water cooled machines The building structure should be designed to take the weight of equipment Suitable vibration control must be considered and adequate load bearing beams and columns must be available for lifting and shifting of such equipment Central systems are generally designed as concealed systems and the visible distribution grilles etc can be easily blended with the aesthetics Central HVAC system may serve multiple thermal zones and have their major components located outside the zone s being served usually in some convenient central location Central HVAC systems will a control point for each thermal zones The controls are field wired and are integrated to central control panel The controls are complex and depend on the type of system Constant air volume CAV systems alter the temperature while keeping the constant air delivery CAV systems serving multiple zones rely on reheat coils to
76. Cooling Towers Water based HVAC systems offer significant energy savings due to the ability of water to transport large quantities of heat over relatively long distances more efficiently than air based systems Additionally they offer the advantages like smaller equipment size and cost along with reduced maintenance and extended life of mechanical equipment However for water scarce urban centers in India the viable installation and operation of cooling towers will require balancing needs for energy efficiency and water conservation simultaneously Given below are some considerations for improving energy and water efficiency of water based cooling towers Energy Efficiency Measures e Proper site selection and sizing of the tower can reduce fan speed capacity and sound and help to conserve energy usage Centrifugal fans in favor of lower energy axial fans can reduce horsepower by 50 or more for the same capacity Fan control through two speed motors pony motors or variable speed motors ECBC 5 2 3 3 Water Efficiency Measures e An optimized bleed rate for the tower should be maintained to regulate water consumption The evaporation rate is dependent on the load which can vary widely and a constant bleed rate usually discharges more water than required A properly operating conductivity meter can automatically control bleed to the proper amount required to maintain the desired tower chemistry in the system at all times Contamina
77. EN EAAS clii LIST OF FIGURES Figure 1 Consumption of Electricity by Sector cccccccccccccccccsssessceccesssesseccesesssceccessseessecessesesesccssseeeseesesseeeseeesesseeees 2 Figure 2 Design Process for the Whole Building Performance Method ssssssessesssesssssserssesseesseessesserssesssrsserssessrssessersses 11 Foure STS i EMODE eE EEEE EEEE 14 Pae aer e a oaan sa EA EE E E EAE EE EA EAEE 15 E E S a Om E PA TA P O AA IAA AE IAN EE AEEA AE A AA 15 Figure 6 Heat and Air Movement through Double Glazing Window System cccccccsesssecsseeesceeseeeesseeeseeesseeesseeenseens 23 Figure 7 Example of UV ae SHGC and VT ses aaasvrseiessreerraeasceineaeses ete ere E EEN ENESE EEAS EEEE EE ESSE 23 Feeney 1B ls aa i TE A E AE AOE 27 Figure 9 Typical Insulation Techniques for RCC Roof Construction ccccscccssscesssesscceesecesscessecesseeesseeenssenseeenseenseeens 29 Faure Ir Opgue Wallisin aner Eten CF OUUC TREN EMT cn T Sy avOn Oy SPE ed Or TUBE VOTE STOP SETI N 33 Fieure Ti Frojecion Calcat oise Sar mene ne Remy nr Feeney OY REMCT Or POR REES 44 Figure 12 Light Shelf Examples and Design 1p Seieied ccssinsconstacvecteowescecasviadevesvieessasunaiesesssadsthvcuudatsceiceteuhsviasstewiecuavendcs 48 Foure Ie Sbolipehtr isaliini a A 51 Figure 14 Cooling Load Reduction Measures ccccssssessscsssscessseesscessesesseessseessceesecesseeessecessesenseceseecesesesesenseeeseeesseesseees 60 Figure 15 Cross Ventilation SchematiC sisiniioretsrai
78. Energy Conservation Building Code 3C USER GUIDE EC DRAFT PLEASE DO NOT CITE OR CIRCULATE MARCH 25 2009 This report is made possible by the support of the American People thro igh the United States Agency for International Development USAID It was prepared by International Resources Group IRG USAID INDIA ENERGY CONSERVATION BUILDING CODE ECBC USER GUIDE DRAFT PLEASE DO NOT CITE OR CIRCULATE March 20 2009 USAID ECO III PROJECT The Energy Conservation and Commercialization ECO Program was signed between the Government of India GOD and USAID in January 2000 under a Bilateral Agreement with the objective to enhance commercial viability and performance of Indian energy sector and to promote utilization of clean and energy efficient technologies in the sector Following the enactment of the Energy Conservation Act 2001 ECO I Project supported GOI in the establishment of the Bureau of Energy Efficiency BEE Support to BEE was provided to set up procedures and authorities establish office facilities and assist in several activities leading to the development of BEE s Action Plan including thrust area such as the development of an energy auditor certification program ECO II Project provided BEE with necessary technical assistance and training support to implement two thrust areas of the Action Plan The first area was to develop the Energy Conservation Building Codes ECBC for
79. Figure 34 Manually operated window shading devices such as blinds or shades are not required to be modeled However any permanent shading devices such as fins overhangs and light shelves are required to be modeled as they have a significant impact on the overall heat gain into the building CXXIV The project does not use any labeled window frame so the project s proposed design needs to comply with the requirement of the ECBC standard as specified in Table 11 1 of Appendix C As per the standard the U value of the window assembly is 7 1 W m2K The SHGC of the glass is 0 20 as given by the manufacturer since the glass is labeled and the visible transmittance is 0 22 as in the original proposed design The simulation model should also include an accurate definition of the floor slab and the roof assembly including specification of the thermal mass specific heat and density as well as resistance to heat flow U factor or R value For exterior roofs other than roofs with ventilated attics the reflectance and emittance of the proposed roof surface provided with the building material specifications shall also be modeled The reflectance and emittance shall be tested in accordance with Section 4 3 1 1 of ECBC 9 2 4 2 Lighting The installed electric lighting power designed for the proposed design should be modeled accurately in the proposed design simulation model This lighting power density generally differs from the standard value speci
80. Material Storage For Medium Bulky Material Storage Parking Garage Garage Area Transportation For Airport Concourse For Air Train Bus Baggage Area For Ticket Counter Terminal LPD W m 12 9 N D N o1 NI O A O or N D on ho N P o lo ol wN oO on C h 9 _ 16 1 12 9 23 7 15 1 12 9 18 3 22 6 12 9 11 8 11 8 10 8 18 3 16 1 18 3 18 3 29 1 24 8 15 1 15 1 10 8 Second for each space that is enclosed by partitions which are 80 or greater than ceiling height the gross interior floor area must be determined This applies to all space area types except for 102 retail The gross interior floor area should be calculated by measuring to the center of the partition walls and must also include spaces allotted to balconies or other projections Finally the individual lighting power allowances for each space is determined by multiplying its gross lighted floor area by the allowed lighting power density for that space The lighting power allowances are summed to equal the Interior Lighting Power Allowance for the building Example 9 Allowed Lighting Power Calculation Space Function Building type New general office space occupying tenant area totally 10 000 m2 Allowable lighting power A combination of general office and corridor restroom and support areas The total allowed watts for the building is determined by multiplying the watts per m fo
81. OLAR RADIATION OUTWARD HEAT FLOW BY CONVECTION AND RADIATION TRANSMITTED RADIATION Source ASHRAE Fundamentals Handbook 2004 Simplified calculations are based on the observation that temperatures of the sky ground and surrounding objects and hence their radiant emission correlate with the exterior air temperature The radiative interchanges are then approximated by assuming that all radiating surfaces including the sky are at the same temperature as the outdoor air With this assumption the basic equation for the instantaneous energy flow Q through a fenestration system combination of the glazing frame and shading devices is Q PAL At sue t t SEGO Appie 100 1 18 Where O instantaneous energy flow W U overall coefficient of heat transfer U factor W m K CLXII fin interior air temperature C lowe exterior ait temperature C A total projected area of fenestration m SHGC solar heat gain coefficient E incident total irradiance W m The principal justification for Equation 1 18 is its simplicity achieved by collecting all the linked radiative conductive and convective energy transfer processes into U and SHGC NOTE e The U and SHGC are instantaneous performance indices The SHGC indicates how well the product insulates against heat caused by sun falling directly on the glass Lower SHGC is appropriate for hot climates to avoid added heat gain while colder climates
82. Point of Use System with no more than 8 feet of horizontal distance between the water heater and hot water fixtures except laundry Hot Water Recovery System that reclaims hot water from the distribution piping by drawing it back to the water heater or other insulated storage tank Pipe Insulation R 4 or greater insulation applied to 3 4 inch or larger non recirculating hot water mains in addition to insulation required by the Standards Section 1500 first five feet from water heater on both hot and cold water pipes Parallel Piping Individual pipes from the water heater to each point of use Continuous Recirculation Distribution system using a pump to recirculate hot water to branch piping though a looped hot water main with no control of the pump such that water flow is continuous Pipe insulation is required Temperature Recirculation Uses temperature controls to cycle pump operation to maintain recirculated water temperatures within certain limits Pipe insulation is required Time Recirculation Uses a timer control to cycle pump operation based on time of day Pipe insulation is required Time Temp Recirculation Uses both temperature and timer controls to regulate pump operation Pipe insulation is required Demand Recirculation Uses brief pump operation to recirculate hot water to fixtures just prior to hot water use when a demand for hot water is indicated Recitculation Demand w Hot Water Recovery
83. The rate of heat transfer Qconvec by convection from a surface of area A and surrounding air can be written as O commen Mt A T Tp EEEE E E S de eareee we 1 8 Where h heat transfer coefficient W m K Also referred to as film conductance or U Value of air films T temperature of the surface K Ts temperature of the fluid X The numerical value of the heat transfer coefficient depends on the nature of heat flow velocity of the fluid physical properties of the fluid and the surface orientation Equation 1 8 calculates the convective heat transfer between a surface and its surrounding air An alternate version of equation 1 8 can also be estimated to determine the heat flow rate due to the volume of air being circulated between the interior of a building and the outside This heat transfer will depend on the ventilation of ar or the rate of air exchange of air It is given by ek ee 1 9 Where p density of air kg m Vt ventilation rate m3 s C specific heat of air J kg K AT temperature difference To Ti SN If the number of air changes is known then Whetre N number of air changes per hour V volume of the room or space m Thus Qy err TEE ee ere ee er 1 11 Some of the commonly used ventilation rates for specific building types are given below in table 2 0 Table 37 Recommended Air Change Rates Hospital wards smoking cing itchens Domestic smoking So
84. a Replacement of glass in an existing sash and frame provided the U factor and SHGC of the replacement glazing are equal to or lower than the existing glazing b Modifications to roof ceiling wall or floor cavities which are insulated to full depth with insulation c Modifications to walls and floors without cavities and where no new cavities are created 3 1 4 2 Heating Ventilation and Air Conditioning Alterations to building heating ventilating and air conditioning equipment or systems shall comply with the requirements of Error Reference source not found applicable to the portions of the building and its systems being altered Any new equipment or control devices installed in conjunction with the alteration shall comply with the specific requirements applicable to that equipment or control device 3 1 4 3 Service Water Heating Alterations to building service water heating equipment or systems shall comply with the requirements of Error Reference source not found applicable to the portions of the building and its systems being altered Any new equipment or control devices installed in conjunction with the alteration shall comply with the specific requirements applicable to that equipment or control device 3 1 4 4 Lighting Alterations to building lighting equipment or systems shall comply with the requirements of Error Reference source not found applicable to the portions of the building and its systems being altered New l
85. aded equipment performance The ECBC contains requirements for duct insulation and hydronic piping insulation that minimize distribution losses Additional improvement can be captured with high efficiency fans diffusers and other components The use of non vapor compression cooling techniques can help save 20 30 energy per unit of cooling as conventional cooling equipment These alternatives include natural ventilation with cool outside air ground coupled cooling night sky cooling evaporative cooling absorption cooling and desiccant systems fuelled by natural gas waste heat or solar energy High efficiency chillers pumps and fans multiplexed chillers to minimize part load operation penalties large heat exchangers low friction duct layout and sizing low pressure drops in air handling and piping components and overall optimization of the entire HVAC system will further help in making the system more efficient see Table 17 Finally the overall system performance can be enhanced by improving the HVAC controls by use of better algorithms sensors signal delivery user interface simulators and other measures Table 17 Energy Savings Potential in HVAC System Designs Component Cooling Load kW ton Improvement i o Conventional Design Optimized Design Penante e AirDistibuton System 060 os Jox ECBC Requirements ECBC includes provisions for most HVAC system types All cooling equipment is required to meet or excee
86. age current power etc Multifamily high rise multifamily structures of four or more stories above grade Multifamily low rise multifamily structures of three or less stories above grade Parapet Multiplication factor indicates the relative reduction in annual solar cooling load from overhangs and or side fins with given projection factors relative to the respective horizontal and vertical fenestration dimensions Projection factor H V Non automatic see definition of manual Occupancy sensor a device that detects the presence or absence of people within an area and causes lighting equipment or appliances to be regulated accordingly Opaque all areas in the building envelope except fenestration and building service openings such as vents and grilles Orientation the direction an envelope element faces i e the direction of a vector perpendicular to and pointing away from the surface outside of the element For vertical fenestration the two categories are north oriented and all other Outdoor outside air air that is outside the building envelope or is taken from the outside the building that has not been previously circulated through the building Overcurrent any current in excess of the rated current of the equipment of the capacity of the conductor It may result from overload short circuit or ground fault Packaged Terminal Air Conditioner PTAC a factory selected wall sleeve and separate unencased
87. ainable Roofing Strategies Available from http www construction com CE articles 0707roofing 3 asp 31 Interesting Fact related to Cool Roof implementation Source Akban H S Menon and A Rosenfeld 2008 Global cooling increasing solar reflectance of urban areas to offset CO2 Most existing flat roofs are dark and reflect only 10 to 20 of sunlight Resurfacing the roof with a white material that has a long term solar reflectance of 0 60 or more increases its solar reflectance by at least 0 40 Akbari e al estimate that so retrofitting 100 m 1000 ft of roof offsets 10 tons of CO2 emission For comparison purposes we point out that a typical US house emits about 10 tons of COz per year Emitted COz is currently traded in Europe at about 25 ton making this 10 ton offset worth 250 It is fairly easy to persuade or to require the owners SS ea of buildings to select white materials for flat roofs f i UN y5 and in California this has been required since 2005 A C ENTEL O However the demand for white s oped roofs is eg limited in North America so California Te compromises by requiring only cool colored surfaces for sloped roofs This rule takes effect in July 2009 Use of cool colored surfaces increases solar reflectance by about 0 20 and yields a CO2 offset of about five tons per 100 m2 or about half that achieved with white surfaces The solar reflectance of pavement can be raised on averag
88. alling directly on the glass The ECBC will recommend the SHGC and U Value you should have for your specific Climate Zone Lower SHGC is appropriate for hot climates to avoid added heat gain while colder climates have higher SHGC requirements Default values are available in Appendix C of the code The Solar Heat Gain Coefficient SHGC is the ratio of the solar heat gain entering the space through the fenestration area to the incident solar radiation Solar heat gain includes directly transmitted solar heat and absorbed solar radiation which then enters the space through radiation conduction or convection In hot climates SHGC is the most important performance characteristic of fenestration more important than the U factor With a lower number less sunlight and heat can pass through the glazing The SHGC is based on the properties of the glazing material the number of panes of glass in the window and the window operation either operable or fixed Glazing units with a low SHGC will help reduce the air conditioning energy use during the cooling season The ECBC requires that SHGC be determined in accordance with ISO 15099 by an accredited independent laboratory and labeled and certified by the manufacturer or other responsible party SHGC has replaced the shading coefficient SC as the figure of merit for solar heat gain through fenestration products SC does not account for the fenestration frame and is determined for the center of glass Furt
89. along parpet PEC Light weight filling of earthen pots of varied sizes 250 mmdwipe hole pipes 230 mm brick wall witg exterior Plaster 236 the Brick wail with tiutertai Ex intervat Piaster Tile in the Floor Finish Ex Vats Scared Nor Woven Polyester Geotextile Foamular Metric insulation 4 fan water Prochirg Systern Marmhrane Typa Scared with Slope RCC Slab weer 4 3 1 1 Cool Roofs Depending on the material and construction a roof will have different properties that determine how it conducts heat to the inside of the building Cool roods are roofs covered with a reflective coating that has a high emissivity property the characteristic of emitting infrared energy that is very effective in reflecting the sun s energy away from the roof surface These cool roofs stay 10 to 16 degrees C cooler than a normal roof under a hot summer sun this quality greatly reduces heat gain inside the building and the cooling load that needs to be met by the HVAC system In hot climates cool roofs or high emittance roof surfaces are an effective way to reduce solar gains and cut building owners energy costs Because cool roofs gain less heat than normal roofs they reduce the need for air conditioning and make buildings more comfortable to the people inside The light color reflects sunlight and heat away from the building and the high emittance allows heat to escape to the atmosphere when the surface beco
90. an enclosed space within a building The classifications of spaces are as follows for the purpose of determining building envelope requirements Conditioned space a cooled space heated space or directly conditioned space Semi heated space an enclosed space within a building that is heated by a heating system whose output capacity is greater or equal to 10 7 W m 3 4 Btu h ft of floor area but is not a conditioned space Enclosed Space space within a building that is not conditioned space or a semi heated space Crawlspaces attics and parking garages with natural or mechanical ventilation are not considered enclosed spaces Standard Design A computer representation of a hypothetical design based on the actual proposed design as per Appendix B Whole Building Performance Method Story portion of a building that is between one finished floor level and the next higher finished floor level or the roof provided however that a basement or cellar shall not be considered a story Supply Air Air being conveyed to a conditioned area through ducts or plenums from a heat exchanger of a heating cooling absorption or evaporative cooling system Supply air is commonly considered air delivered to a space by a space conditioning system Depending on space requirements the supply may be either heated cooled or neutral System a combination of equipment and auxiliary devices e g controls accessories interconnecting means and terminal e
91. ard air leakage through cracks and crevices in any building element and around windows and doors of a building caused by pressure differences across these elements due to factors such as wind inside and outside temperature differences stack effect and imbalance between supply and exhaust air systems Installed interior lighting power the power in watts of all permanently installed general task and furniture lighting systems and luminaires Integrated part load value a single number figure of merit based on part load EER COP or KW ton expressing part load efficiency for air conditioning and heat pump equipment on the basis of weighted Operation at various load capacities for the equipment Kilovolt ampere where the term kilovolt ampere kVA is used in this Code it is the product of the line cutrent amperes times the nominal system voltage kilovolts times 1 732 for three phase currents For single phase applications kVA is the product of the line current amperes times the nominal system voltage kilovolts Kilowatt the basic unit of electric power equal to 1000 W CXXXVI Labeled equipment or materials to which a symbol or other identifying mark has been attached by the manufacturer indicating compliance with specified standard or performance in a specified manner Lamp a generic term for man made light source often called bulb or tube Lighted floor area gross the gross floor area of lighted spaces Lighting d
92. area is 900 m2 How many controls are required for this space A Four since this space is smaller than 1 000 m each space control can serve a maximum area of 250 m2 96 Q In an open office 1 500 m2 how many controls are required A Two since this space is larger than 1 000 m2 each control can serve a maximum area of 1 000 m2 Q A medical laboratory is studying the effect of lighting on a chemical process Ordinary fluorescent luminaires are arranged over the test branch and connected to timers This lighting is separate and distinct from the general lighting used throughout the laboratory Is either the general lighting or the test lighting exempt A The general lighting is covered by the Code The test lighting is exempt However the test lighting should have separate controls Table 262 Lighting Diagrams Manual on switch mounted ocupancy sensor 3 Lamp pendent mounted direct Indirect T8 luminaire mounted in the center of the office Plug in articulated A and under cabinet task light ot My Pi ks t 26 wall CFL wall washers ener behind reception and seating areas RA Articulated Task Light 2 lamp pendent indirect i over reception desk om F 3 3 a en f s basrssssaag 7 2 2 Exit Signs Electrically powered exit signs use either incandescent bulbs compact fluorescent lamps CFL or light emitting diode LED arrays as light sources The ECBC mandates the ma
93. as for control device requirements 47 EXTERIOR SHADING DEVICES DESIGN TIPS Design the building to shade it Use the building form itself to provide exterior shading by recessing the window back in a deeper wall section or extending elements of the skin to visually blend with envelope structural features Use a horizontal form for south windows For example awnings overhangs recessed windows Also somewhat useful on the east and west Serves no function on the north Use a vertical form on east and west windows For example vertical fins or recessed windows Also useful on north to block early morning and late afternoon low sun Give west and south windows shading priority Morning sun is usually not a serious heat gain problem If your budget is tight invest in west and south shading only Design shading for glare relief as well Use exterior shading to reduce glare by partially blocking occupants view of the too bright sky Exterior surfaces also help smooth out interior daylight distribution The shade s color modifies light and heat Exterior shading systems should be light colored if diffuse daylight transmittance is desired and dark colored if maximum reduction in light and heat gain is desired Fixed versus movable shading Use fixed devices if your budget is tight Use movable devices for more efficient use of daylight and to allow occupant adjustment first cost and maintenance costs are highe
94. assemblies that normally include indoor conditioning coil compressor and outdoor coil including means to provide a heating function Heat pumps provide the function of air heating with controlled temperature and may include the functions of air cooling 72 5 3 1 Economizers An economizer is simply a collection of dampers sensors actuators and logic devices that together decide how much outside air to bring into a building See Figure 17 Economizers allow the use of outdoor air to cool the building when the outside temperature is cooler than that inside Under the right conditions sensors and controls will shut down the compressor and bring in the outside air through the economizer louvers This saves energy by eliminating unnecessaty cooling A properly operating economizer can cut energy costs by as much as 10 percent of a building s total energy consumption depending mostly on local climate and internal cooling loads 5 3 1 1 Air and water side economizers The ECBC requires each individual cooling fan system that has a design supply capacity over 1 200 I s 2 500 cfm and a total mechanical cooling capacity over 22 kW 6 3 tons to include either an air or water economizer Where an air economizer is used it must be capable of modulating outside air and return air dampers to supply 100 percent of the design supply air quantity as outside air When a water economizer is used it must be capable of providing 100 of the exp
95. astering U value 0 419 Btu sq ft F 2 38 W sq m K Ground floor 1 plastering RCC 4 Slab outside to inside U value 0 630 Btu sq ft F 3 58 W sq m K Internal floor RCC 4 Slab 0 5 plastering 0 5 Ceramic tiles outside to inside U value 0 641 Btu sq ft F 3 64 W sq m K Airtightness 0 2 ACH Table 32 Openings Internal partitions Standard Design 0 5 Plaster 9 Clay brick insulation 0 5 Plastering outside to inside U value 0 44 W sq m K Overdeck insulation RCC 4 Slab 0 5 plastering outside to inside U value 0 072 Btu sq ft F 0 409 W sq m K 0 5 Plaster 9 Clay brick 0 5 Plastering U value 0 419 Btu sq ft F 2 38 W sq m K 1 plastering RCC 4 Slab insulation 0 5 plastering outside to inside U value 0 350 Btu sq ft F 1 99 W sq m K 1 plastering RCC 4 Slab insulation 0 5 plastering outside to inside U value 0 350 Btu sq ft F 1 99 W sq m K 0 2 ACH ooo o o sene Design U value 1 22 Btu sq ft F Since U value 0 573 Unlabeled U value as per ECBC 1 25 Btu sq ft F closest one selected from DB library SHGC 0 33 SHGC 0 244 VLT 0 22 VLT 0 232 Not model as the frame is unlabeled U value of glazing is U value of the assembly Internal None Internal None External None External None Base case glazing U value is of ans complete assembly Frames and dividers Shading CXXVIII Table 33 Lighting CE Proposed Building Standard Design A Conditioned r
96. at mechanical work electrical and chemical Customary measurements are watts W Energy Efficiency Ratio EER Performance of smaller chillers and rooftop units is frequently measured in EER rather than kW ton It is the ratio of net cooling capacity in Btu h to total rate of electric input in watts under designated operating conditions The higher the EER the more efficient the unit Energy Factor EF a measure of water heater overall efficiency Envelope performance factor The trade off value for the building envelope performance compliance option calculated using the procedures specified in Section 12 Appendix D For the purposes of determining building envelope requirements the classifications are defined as follows Base envelope performance factor the building envelope performance factor for the base design Proposed envelope performance factor the building envelope performance factor for the proposed design Equipment devices for comfort conditioned electric power lighting transportation or service water heating including but not limited to furnaces boilers air conditioners heat pumps chillers water heaters lamps luminaries ballasts elevators escalators or other devices or installations Equipment existing equipment previously installed in an existing building Facade area area of the fa ade including overhanging soffits cornices and protruding columns measured in elevation in a vertical plane parall
97. at an angle of 60 from horizontal or greater This includes above and below grade walls between floor spandrels peripheral edges of floors and foundation walls Wall above grade a wall that is not below grade Wall below grade that portion of a wall in the building envelope that is entirely below the finish grade and in contact with the ground Wall area gross the overall area off a wall including openings such as windows and doors measured horizontally from outside surface to outside service and measured vertically from the top of the floor to the top of the roof If roof insulation is installed at the ceiling level rather than the roof then the vertical measurement is made to the top of the ceiling Note that does not allow roof insulation to be located on a suspended ceiling with removable ceiling panels The gross wall area includes the area between the ceiling and the floor for multi story buildings Water heater vessel in which water is heated and is withdrawn for use external to the system Parapet Parapet Weather stripping Materials such as a insulation in roof strip of fabric plastic rubber or metal or a device used to seal the openings gaps or cracks of venting window and door units to prevent water and air infiltration Insulation at Ceiling Vertical Dimension 5 T Window Wall Ratio WWR is the ratio of vertical fenestration area to gross exterior wall area Gross exterior wall area is
98. at between the steady temperature of the earth water and a building to maintain the building space conditions The stable underground or under water temperatures provides a source for heat in the winter and a means to reject excess heat in the summer In a geo exchange system a fluid is circulated between the building and the ground loop piping In the summer the fluid picks up heat from the building and moves it to the water earth In the winter the fluid picks up heat from the ground water and moves it to the building 76 Thermal energy storage This refers to technologies that store energy in a thermal reservoir for later reuse They can be employed to balance energy demand between day time and night time The thermal reservoir may be maintained at a temperature above hotter or below colder than that of the ambient environment The principal application today is the production of ice chilled water or eutectic solution at night which is then used to cool environments during the day Thermal energy storage technologies can store heat even from solar collectors in an insulated repository for later use in space heating domestic or process hot water or to generate electricity Most practical active solar heating systems have storage for a few hours to a day s worth of heat collected Variable Refrigerant Flow VRF Systems This technology is used to transfer heat from warmer parts of the building to cooler parts The term variable ref
99. at the insulation is well bonded to the outside of the framing It is important to install insulation in exterior corners and on or in headers over doors and windows This can eliminate excess heat transfer through the surfaces Concrete masonry unit walls may be insulated by filling the empty core with perlite vermiculite or some other insulating material In some cases even with filled cores these wall types require additional insulation The insulation will either be installed between framing members typically on the inside of the wall or as continuous rigid board insulation on the inside or outside of the wall In either case make sure that the insulation is installed properly and that the insulation R value matches the plans or documentation Thermal Values of Common Construction Materials Brick concrete stone and plastering material are all common materials in India used for opaque wall construction Summary of each material along with tables describing basic thermal properties is given below Bricks These ate locally produced and vary in the quality of the raw material manufacture process and finished product Standard burnt clay bricks follow Indian Standard IS 1077 1992 which specifies a compressive strength of less than 40 N mm2 Also commonly used are Burnt Clay Fly Ash Bricks which have higher compressive strength than the standard bricks Burnt Clay Hollow Bricks are a third type of brick available these have e
100. ate climate zones the point of condensation is usually on the inside surface of the exterior sheathing Moisture carried by airflow through the wall is deposited at the backside of the sheathing and accumulates In hot and humid climates where air flow is traveling from the outside to the inside warm moist air from the outside will be cooled on the way to the air conditioned inside releasing moisture within the wall cavity Air retarding wraps are a breathable membrane with microscopic pores that allow the moisture vapor to dissipate helping to dry out a wall system and avoid damage 36 Insulation There are many types of insulation materials available Some materials are blown or sprayed in their application which can provide additional air sealing benefits as described in Table 6 Different types of insulation for framed walls may be used including e Fiberglass batts R values should be printed on the craft backing of the insulation or on the insulation itself for unfaced batts e Rigid foam boards R values should be printed on the craft backing of the insulation e Blown in or sprayed insulation the installer should provide a certification of the installed density and R value Table 6 Types of Insulation for Roofs and Walls Method of Installation Where Applicable Blankets Batts or Rolls Fiberglass Rock wool Loose Fill Spray applied Rock wool Fiberglass Cellulose Polyurethane foam Rigid Insulation Extr
101. atic zones and rural housing in India Krishan et al 2001 Climate responsive architecture A design handbook for energy efficient buildings Table 36 Climate Zone of the Major Indian Cities Indian Cities and their respective Climatic Zones City Jorhat Kota Kurnool Lucknow Madras Manglore Nagpur Nellore New Delhi Panjim Patna Pune Raipur Rajkot Ramgundam Ranchi Ratnagiri Raxaul Saharanpur Shillong Sholapur SunderNagar Surat Tezpur Tiruchchirapalli Trivandrum Tuticorin Veraval Vishakhapatnam Climatic Zone Warm amp Humid Hot amp Dry Warm amp Humid Composite Warm amp Humid Warm amp Humid Composite Warm amp Humid Composite Warm amp Humid Composite Warm amp Humid Composite Composite Warm amp Humid Composite Warm amp Humid Warm amp Humid Composite Warm amp Humid Hot amp Dry Cold Hot amp Dry Warm amp Humid Warm amp Humid Warm amp Humid Warm amp Humid Warm amp Humid Warm amp Humid CL 2 SUPPLEMENTAL MATERIALS 12 1 HEAT TRANSFER FUNDAMENTALS AND CALCULATIONS 12 1 1 Heat Flow Basics Knowledge of the fundamentals of heat transfer and solar radiation are crucial in understanding the underlying processes that take place in a building and its interaction with the external environment Various heat exchange processes are possible between a building and the external environment Figure 37 and between a human body and a building s internal environment Figure 38
102. ation and any wood foundation element to provide a termite inspection area When rigid board insulation extends above ground protect the insulation by covering it with stucco or another suitable protective coating What are Structural Insulated Panels Structural Insulated Panels SIPS are an advanced method of constructing walls roofs and floors SIPS consist of rigid insulation usually expanded polystyrene sandwiched between two sheets of OSB or plywood Little or no structural framing penetrates the insulation layer Panels are typically manufactured at a factory and shipped to the job site in assemblies that can be as large as 8 ft by 20 ft In the field the SIPS panels are joined in one of two ways and the choice affects thermal performance What is Spray Polyurethane Foam Spray polyurethane foam commonly referred to as SPF is a spray applied insulating foam plastic that is installed as a liquid and then expands many times its original volume SPF formulas can be adjusted to have many different physical properties depending on the use desired For example the same basic raw materials can make insulation foam that is semi rigid and soft to the touch and also create high density roofing foam that is resistant to foot traffic and water 35 Spandrel panels and glass curtain walls Wood frame Table IV 9 U factors of Wood Framed Walls Concrete Table IV 13 Properties of Solid Unit Masonry and Solid Concrete Walls
103. ave spectrally selective glass The SHGC rating for the product is the key to determining whether you have glass with a spectrally selective coating In general windows with a spectrally selective low e coating will have SHGC ratings of 0 40 or lower 4 4 BUILDING ENVELOPE TRADE OFF OPTION Formulas in Appendix D guide calculation of the envelope performance factor This is calculated for a subject building AND for a standard design standard design refers to a building envelope exactly meeting prescriptive requirements For compliance the subject building s performance factor must be less than that of the standard design 53 5 HEATING VENTILATION AND AIR CONDITIONING 5 1 GENERAL Overview Heating Ventilation and Air Conditioning HVAC refers to the equipment distribution network and terminals that provide either collectively or individually the heating ventilating or air conditioning processes to a building The HVAC system accounts for significant portion of a commercial building s energy use approximately 40 percent However proven technologies and design concepts can be used to build energy efficiencies in the system and generate sionificant energy and cost savings HVAC systems are also critical for their effect on the health comfort and productivity of occupants Issues like user discomfort improper ventilation and poor indoor air quality are linked to HVAC system design and operation and can be improved
104. be clearly labeled to identify the controlled lighting device 7 2 1 3 Control in Daylighted Areas ECBC requires controls photo sensors etc that can reduce the light output of luminaires in any day lit space by at least half All luminaires in daylighted areas greater than 25 m2 250 ft2 must have a manual or automatic control device that is capable of reducing the light output of the luminaires in the daylighted areas by at least 50 and controlling only the luminaires located entirely within the daylighted area Figure 21 Requirements for Space Controls Space gt 1 000 m2 10 000 Space lt 1 000 m2 Space control must Space control must control a maximum control a maximum of of 250 m2 2 500 1 000 m 10 000 ft2 Daylighted Areas In general Daylighted Area refers to the daylight illuminated floor area under horizontal fenestration skylight or adjacent to vertical fenestration window For horizontal fenestration the daylighted area is specifically the area under a skylight monitor or sawtooth configuration with an effective aperture greater than 0 001 0 1 For both vertical and horizontal fenestration the daylighted area is calculated as the horizontal dimension in each direction equal to the top aperture dimension in that direction plus either The floor to ceiling height H for skylights or 1 5 H for monitors or H or 2H for the sawtooth configuration or The distance to the nearest 1000 mm
105. ble speed option Local systems have life expectancies of 15 years or less Local systems maintenance may often be relatively simple but such maintenance may have to occur directly in occupied spaces The energy utilization of local compact units can be simply measured by installing a local energy meter with each unit Local system units cannot be easily connected together to permit centralized energy management operations Local systems can be integrated to BMS with respect to on off functions through electric circuit control but more sophisticated central control such as night setback or economizer operation is not possible Packaged and split units have much lower first costs than a central system The operating costs of unitary systems is usually higher due to lower efficiency ratings and lower part load performance values The potential for adoption of high tech energy efficiency measures is very limited Source A Bhatia Course Content PDH 149 HVAC Design Aspects Choosing A Right System Central V s Compact Systems http www pdheenter com Heating System Types Heating system types can be classified fairly well by the heating equipment type The heating equipment used in Indian commercial buildings includes boilers oil and gas furnaces oil gas and electric heat pumps and space heaters Boiler based heating systems have steam and or water piping to distribute heat Boilers can be self contained unit
106. buildings Each new building must have a minimum of 60 points Buildings that exceed the minimum point requirement may be eligible for certain benefits such as relaxation of certain zoning rules Enforcement Systems Enforcement is critical for the standard to have an effect Not all countries have mandatory building energy standards India for example has a voluntary code Japan s standard is also technically voluntary although Japan has recently adopted penalties for non compliance that blur this distinction The U S Canada and Australia all adopt building standards at the local level Not all jurisdictions in the U S and Canada have adopted their nation s model building energy code Some important issues regarding enforcement and the related impact of the code on energy use include the point of compliance design and or construction stage how buildings are checked and by whom penalties and other incentives for compliance training and information on the code compliance tools such as code compliance software and inspection checklists equipment and material testing and ratings In the U S Canada Australia and Korea for example the building design must be approved and inspectors check the building for compliance at least once during construction In Japan parts of Europe and the former Soviet Union the checks only occur at the building design stage China uses a combination of government employees and certified companies to chec
107. cated in the warm humid climate zone can comply under the following conditions 1 WWW lt 40 and SHGC lt 0 25 Or 2 40 lt WWRS60 and SHGC lt 0 20 This building complies under the first criteria Fenestration Area 1 598 sqft or 148 5 m Tou Tin 30 24 C or 303 15 297 15 K 6 Using equation 1 18 Q 3 30 148 5 6 0 22 148 5 111 3 2940 3 3636 17 6576 47 W or 6 57 kW 12 1 7 Thermal Transmittance U FACTOR of Fenestration In the absence of sunlight air infiltration and moisture condensation the first term in Equation 1 1 8 represents the rate of thermal heat transfer through a fenestration system Most fenestration systems consist of transparent multipane glazing units and opaque elements comprising the sash and frame called frame The glazing unit s heat transfer paths include a one dimensional center of glass contribution and a two dimensional edge contribution The frame contribution is primarily two dimensional CLXIV Consequently the total rate of heat transfer through a fenestration system can be calculated knowing the separate heat transfer contributions of the center glass edge glass and frame When present glazing dividers such as decorative grilles also affect heat transfer and their contribution must be considered The overall U factor is estimated using area weighted U factors for each contribution by Us Where the subscripts g eg and frefer to the center of glas
108. ce area Orientation and shape of building Use of trees as wind barriers CUwizeneattomappranes O O COMPOSITE CLIMATE ZONE Thermal Requirements Physical Manifestation Resist Heat Gain in Summer and Resist Heat Loss in Winter Decrease exposed surface area Orientation and shape of building Use of trees as wind barriers Increase shading Walls glass surfaces protected by overhangs fins and trees Increase surface reflectivity Pale colour glazed china mosaic tiles etc Promote Heat Loss in Summer Monsoon Dehumidifiers desiccant cooling Source Nayak and Prajapati 2006 Handbook On Energy Conscious Buildings Compliance Approaches After establishing the specific climate zone in which the building is located determine which compliance approach is the best fit for your design The ECBC allows the following approaches 19 Prescriptive Approach This is a standard component based approach using look up tables that assign minimum thermal performance requirements U Values R Values SGHC etc for each element roofs opaque walls vertical fenestration and skylights based on five different climate zones This approach is quick and easy to use but this approach is somewhat restrictive because requirements have to be met exactly as specified The prescriptive requirements for insulating levels of opaque components such as roofs and walls are based on each of the five climate zones in terms of a max
109. charge damper fan vortex damper fan inlet or fan speed change 8 Minimize exhaust and make up air Makeup air depends on the needs of ventilation for personnel exhaust air from workspaces overcoming infiltration machine air needs and federal state and local requirements e Seal ducts that run through unconditioned space up to 20 percent of conditioned air can be lost in supply duct run e Keep doors closed when air conditioning is running e Properly insulate walls and ceilings e Insulate air ducts chilled water hot water and steam pipes e Rewire fans to operate only when lights are switched on as codes permit e Check for damper leakage ensure tight seals e Shut off unneeded exhaust fans and reduce use where possible e Reduce air volume lost by reducing exhaust rates to the minimum e Review process temperatures e Install thermal windows to minimize cooling and heating loss 9 Implement a regular maintenance plan e Inspect to ensure dampers are sealed tightly e Clean coil surfaces e Ensure doors and windows have tight seals e Check fans for lint dirt or other causes of reduced flow e Schedule HVAC tune ups the typical energy savings generated by tune up is 10 percent e Check and calibrate thermostat regularly e Replace air filters regularly e Inspect ductwork e Repair leaks e Turn off hot water pumps in mild weather Maintenance for an expert e Reduce fan speeds and adjust belt drives e Check valves dampers
110. climate change during which we can take further measures to improve energy efficiency and sustainability Equivalent Car Offsets from Cool Roofs 4 3 2 Opaque Walls All walls between the outdoors and conditioned space or unconditioned space must be insulated As shown in Error Reference source not found these include e Exterior walls e Knee walls in attics 32 e Perimeter joists e Walls between a conditioned space and an unconditioned space such as in a warehouse e Skylight wells Opaque walls can meet the component requirements by either using a construction that has an assembly U factor lower than the specified criteria as shown in ECBC Table 4 2 reproduced below in Table 5 or by installing the required R value of insulation R value is for the insulation alone and does not include building materials or air films Appendix C of the Standard has tables of default U factors for all classes of construction For opaque doors the U factor is the only compliance option Figure 10 Opaque Walls Unconditioned Space KNEE WALL Perimeter Joints Table 5 Opaque Wall Assembly U Factor and Insulation R Value Requirements Climate Zone reas HGH TS Cell Cemais i Other Building Types Daytime Maximum U factor Mini R val Maxi i Minimum R Eol inimum R value aximum U factor o oo of insulation alone the overall assembly i assembly 2 C W N insulation alone W m C ase CESS m2 C W Figure 11 P
111. combination of heating and cooling components assemblies or sections It may include heating capability by hot water steam or electricity and is intended for mounting through the wall to service a single room or zone Party wall a firewall on an interior lot line used or adapted for joint service between two buildings Permanently installed equipment that is fixed in place and is not portable or movable Plenum a compartment or chamber to which one or more ducts are connected that forms a part of the air distribution system and that is not used for occupancy or storage A plenum often is formed in part or in total by portions for the building Pool any structure basin or tank containing an artificial body of water for swimming diving or recreational bathing The terms include but not limited to swimming pool whirlpool spa hot tub Process load the load on a building resulting from the consumption or release of process energy Projection factor overhang the ratio of the horizontal depth of the external shading projection divided by the sum of the height of the fenestration and the distance from the top of the fenestration to the bottom of the farthest point of the external shading projection in consistent units Projection factor sidefin the ratio of the horizontal depth of the external shading projection divided by the distance from the window jamb to the farthest point of the external shading projection in consistent unit
112. considerable knowledge of building simulation tools and very close communication between members of the design team Appendix B of the ECBC describes the Whole Building Performance approach for complying with the code This method involves developing a computer model of the proposed design and comparing its estimated energy consumption to a predetermined energy budget for that building See Figure 2 This energy budget represents the upper limit of energy use allowed for that particular building under a scenario where all the ECBC prescriptive requirements were adopted The Energy Budget for the proposed building becomes the Standard Design or base case criteria as described in detail in Appendix B of the ECBC Code compliance will be achieved if the proposed energy budget is no greater than the allowed energy budget Three basic steps are involved 1 Design the building with energy efficiency measures that are expected to be sufficient to meet the energy budget The prescriptive approach requirements provide a good starting point for the development of the design 2 Demonstrate that the building complies with the mandatory measures See sections 4 2 5 2 6 2 7 2 and 8 2 3 Using an approved calculation method model the energy consumption of the building using the proposed features to create the proposed energy budget The model will also automatically calculate the allowed energy budget for the proposed building If the p
113. control the delivered cooling This incurs lot of energy wastage due to simultaneous cooling and heating Space temperature control can also be achieved by applying a variable air volume VAV system which primarily alters the air delivery rates The VAV system may or may not have a reheat coil which provides additional heat when the space does not need to be cooled or needs less cooling than would be delivered by supply air at the terminal box s minimum air quantity setting The quality of air conditioning is comparatively superior with better control over temperature relative humidity air filtration and air distribution Best suited for applications demanding close control of temperature humidity and cleanliness and can be customized as per the design conditions Central systems usually operate under part load conditions and localized areas cannot be isolated for complete shut down under any condition In a central system the individual control option is not always available If individual control is desired the system shall be designed as variable air volume system VAV with localized thermostats No separate plant room space is required as the refrigeration package is integral to the package nit condensing unit which is generally located outdoors Evaporator units are generally located indoors The local systems are smaller in size and are less bulky The appearance of local units can be unappealing a
114. d accepted as authoritative Grade the finished ground level adjoining a building at all exterior walls Guest room any room or rooms used or intended to be used by a guest for sleeping purposes Heat capacity the amount of heat necessary to raise the temperature of a given mass 1 C 1 F Numerically the heat capacity per unit area of surface W m2 C Btu ft F is the sum of the products of the mass per unit area of each individual material in the roof wall or floor surface multiplied by its individual specific heat Heat Pump A heat pump consists of one or more factory made assemblies that normally include indoor conditioning coil compressor and outdoor coil including means to provide a heating function Heat pumps provide the function of air heating with controlled temperature and may include the functions of air cooling air circulation air cleaning dehumidifying or humidifying Heating Seasonal Performance Factor HSPF the total heating output of a heat pump during its normal annual usage period for heating in Btu divided by the total electric energy input during the same period Historic a building or space that has been specifically designed as historically significant HVAC system the equipment distribution systems and terminals that provide either collectively or individually the processes of heating ventilating or air conditioned to a building or portion of a building Infiltration the uncontrolled inw
115. d maximum load being served Does this comply with ECBC requirements No the code requires motors not exceed 200 of the maximum calculated load Since motors run most efficiently near their designed power rating it is good practice to operate between 75 percent and 100 percent of full load rating 108 Relationship of purchase price to operating costs for electric motors and automobiles Many energy using devices cost much more to buy than the energy they use in a year A typical American car under normal use for example costs about 30 times as much to buy as it costs EE Purchase Cost in gasoline each year to run But electric motors m Annual Operating Cost Relationship of purchase price to operating costs for electric motors and automobiles are a notable exception A motor running at a typical commercial or industrial sector duty factor of 4 000 hours per year or more will consume on the order of ten times its capital INR 250 K cost s worth of electricity every year and roughly two hundred times its cost over a 20 year service life Automobiles Electric Motors Example 10 Calculating savings from use of an energy efficient motor This simple calculation will determine the kW saved with an energy efficient motor using two similar motors operating at the same load kW saved hp x L x 0 746 x 100 Estd 100 Ehe kWh savings kW saved x Annual Operating Hours Total Savings kW saved x 12 x monthly demand c
116. d minimum efficiency requirements in the ECBC 5 2 2 Systems not included are referred to ASHRAE 90 1 2004 Single zone unitary systems are covered as well as multiple zone air and water systems The more complex the system the more requirements apply to that system a single zone unitary system has fewer requirements than a complex system made up of chillers boilers and fan coil units For natural ventilation requirements buildings are required to follow the design guidelines provided for natural ventilation in the National Building Code of India 2005 ECBC 5 2 1 Unless following the Whole Building Performance approach for compliance the HVAC system must follow both the mandatory requirements described in ECBC Section 5 2 and the prescriptive requirements described in ECBC Section 5 3 ALL buildings must follow the mandatory requirements 5 2 MANDATORY REQUIREMENTS The ECBC contains mandatory requirements for the following elements of the HVAC system e Equipment efficiency e Controls e Duct insulation e Hydronic piping insulation e Condensers e System balancing FAQs 7 HVAC What are the most important elements of an efficient HVAC system 61 There are four elements e The duct system must have a good design that is planned early in the construction process and understood by the builder framer structural engineer and designer Every fit and bend in the duct system affects the efficiency of the system The
117. d stoves equipped with heat exchangers for heating hot water Temperature Controls Water heating systems are required to have controls that are adjustable down to a 49 C setpoint ot lower An exception is made where a higher setting is recommended by the manufacturer to prevent condensation and possible corrosion To comply with this requirement the water heater must have thermostatic control with an accessible setpoint This setpoint must be adjustable down to whichever is lower 49 C or the minimum manufacturers recommended setting to prevent condensation Both standby and distribution losses will be minimized by designing a system to provide hot water at the minimum temperature required Table 27 Service Water Temperature summarizes the recommended hot water design temperatures In addition to the potential energy savings maintaining water temperature as low as possible reduces corrosion and scaling of water heaters and components Another important benefit is improved safety with respect to scalding Accidental scalding from temperatures as low as 60 C is responsible for numerous deaths each year The Standard requires automatic temperature controls for public lavatory faucets to limit the outlet temperature to 43 C Designers should be aware that the bacteria that cause Legionnaire s disease has been found in service water heating systems and can colonize in hot water systems maintained below 46 C Careful maintenance practices can reduce
118. data input process for the model the project should refer to Appendix E Climate zone map of India in the code to check the climate zone of the building site The building should then be classified either as a 24 hour activity building or a daytime activity building because the ECBC specifications for the U values of the building envelope are mandated according to the climate zone of the building and the occupancy type of the building In this particular case Gandhinagar Gujrat falls under the Hot Dry climate zone of India characteristic of high temperatures intense solar radiation clear skies and low precipitation levels Hot winds are experienced during the day and cool winds at night Hourly weather data representing information about solar radiation temperature humidity wind speed wind direction rainfall atmospheric pressure cloud cover etc for specific locations are stored in weather files All simulation programs require the user to select an appropriate weather file for the site location The simulation program uses the weather data to calculate the heating and cooling loads due to conduction gains and losses solar gain heat gained or lost from outside air and humidification or dehumidification In cases where the weather file for any particular location is not available for the simulation model it is advised to use a nearby station city not more than 2 latitude or 2 longitude 250 kms apart and within 100m altitude of the actua
119. ding including basements mezzanine and intermediate floored tiers and penthouses with headroom height of 2 5 m 7 5 ft or greater It is measured from the exterior faces of exterior walls or from the centerline of walls separating buildings but excluding covered walkways open roofed over areas porches and similar spaces pipe trenches exterior terraces or steps chimneys roof overhangs and similar features Gross building envelope floor area the gross floor area of the building envelope but excluding slab on grade floors Gross conditioned floor area the gross floor area of conditioned spaces Gross lighted floor area the gross floor area of lighted spaces Gross semi heated floor area the gross floor area of semi heated spaces Flue damper a device in the flue outlet or in the inlet of or upstream of the draft control device of an individual automatically operated fossil fuel fired appliance that is designed to automatically open the flue outlet during appliance operation and to automatically close the flue outlet when then appliance is in standby condition Fossil fuel fuel derived from a hydrocarbon deposit such as petroleum coal or natural gas derived from living matter of a previous geologic time Fuel a material that may be used to produce heat or generate power by combustion Generally accepted engineer standard a specification rule guide or procedure in the field of engineering or related thereto recognized an
120. e than central units even though their efficiency is generally lower than that of central air conditioners In a split system central air conditioner an outdoor metal cabinet contains the condenser and compressor and an indoor cabinet contains the evaporator In many split system air conditioners this indoor cabinet also contains a furnace or the indoor part of a heat pump Packaged air conditioners In a packaged air conditioner the evaporator condenser and compressor are all located in one cabinet which usually is placed on a roof or on a concrete slab adjacent to the building This type of air conditioner is typical in small commercial buildings and also in residential buildings Air supply and return ducts come from indoors through the building s exterior wall or roof to connect with the packaged air conditioner which is usually located outdoors Packaged air conditioners often include electric heating coils or a natural gas furnace This combination of air conditioner and central heater eliminatesthe need for a separate furnace indoors Central HVAC Systems Central air conditioners In central air conditioning systems cooling is generated in a chiller and distributed to air handling units or fan coil units with a chilled water system This category includes systems with air cooled chillers as well as systems with cooling towers for heat rejection Table 16 is a comprehensive overview of the differences between local and central HV
121. e Code applies to the fan coils and controls cold water to new fan coils in a building in the addition but not to the existing central addition plant A variable air volume VAV air handler in the The Code applies to the VAV boxes and existing building will provide cool air and controls in the addition but not to the existing outdoor air ventilation to an addition air handler or the central plant that serves it An addition is served by its own single zone The Code applies to the HVAC system and HVAC system controls in the same way that it applies to new construction 3 1 4 Alterations to Existing Buildings When making alterations to an existing building the portions of a building and its systems that are being altered must be made to comply with mandatory and prescriptive requirements as described above for new construction Compliance is required only if the conditioned floor area of the building is 1 000 m 10 000 ft or greater and or the building has a connected load of 500 kW or a contract demand of 600 kVA or greater Specific prescriptive system related requirements for alterations are described within the respective chapter The exception to this requirement is that compliance can also be demonstrated by showing that the entire building complies with the ECBC as if it were a new building e The first approach is to show that each system piece of equipment or component that is being replaced complies individually with
122. e U Value or the thermal transmittance The U Values are calculated for particular elements walls roofs etc by finding the thermal resistances R Values of each component materials including air layers and internal air spaces then adding all the resistances to obtain XR The U Value is the reciprocal of this sum of resistances U Value 1 YR A U factor is also required for opaque constructions default values are provided in Section 11 Appendix C of the code ECBC 4 2 2 The U factor demonstrates insulating capacity and will be used to determine compliance under ECBC sections 4 3 1 and 4 3 2 Example 3 Procedure for determining the U Value for a composite wall assembly Cavity Wall with Plaster Cavity Wall with Plaster ect LZ Z 13 mm Gypum Plaster IS 9498 1980 115 mm Brick wall 50 mm Air Gap Layer 1 13 mm Gypsum Plaster Thickness L1 0 013 m Resistance for Layer 1 R1 0 056 Km2 W Layer 2 115 mm brick wall L2 0 115 m Conductivity for Layer 2 k2 Range of 0 81 0 98 W m K Thus Resistance for Layer 2 R2 can be calculated as follows R2 L2 1 k2 0 115 1 24 1 02 Range of 0 1426 1173 Km 2 W Layer 3 50 mm air gap L3 0 05m k3 0 0352 W m K R3 L3 1 k3 1 4 Km2 W Layer 4 115 mm brick wall L4 0 115 m k4 Range of 0 81 0 98 W m K R4 L4 1 k4 0 115 1 24 1 02 Range of 0 1426 1173 Km2 W 24 Minimum R Value for the composite wall R1i R2 R3 R4 0 056 0 1426 1 4
123. e accessed at http eco3 org downloads 002 Implementationof ECBC Energy Simulation Public Version pdf 3 3 ADMINISTRATIVE REQUIREMENTS Administration and enforcement of the ECBC is carried out by the local authority having jurisdiction This authority is responsible for specifying permit requirements code interpretations approved calculation methods worksheets compliance forms manufacturing literature rights of appeal and other data to demonstrate compliance The authority having jurisdiction will need to receive plans and specifications that show all pertinent data and features of the building equipment and systems This should be provided at a sufficient level of detail to verify that the building complies with the all the requirements of the ECBC The compliance forms can be found in Appendix G of the ECBC The process of designing ECBC compliant buildings will include different stages that begin with the design process obtaining a building permit completing the compliance submittals and finally the construction of the building The process of complying with and enforcing the ECBC will require the involvement of many parties Those involved may include the architect or building designer building developers contractors engineers energy consultants inspectors the owner and third party inspectors Communication between these parties and an integrated design approach will be essential for the compliance enforcement process t
124. e by about 0 15 offsetting about four tons of CO2 per 100 me Over 50 of the world population now lives in urban areas and by 2040 that fraction is expected to reach 70 Pavements and roofs comprise over 60 of urban surfaces roofs 20 to 25 pavements about 40 Akbari e al estimate that permanently retrofitting urban roofs and pavements in the tropical and temperate regions of the world with solar reflective materials would offset 44 billion tons of emitted CO2 worth 1 1 trillion at 25 tonne How can the reader visualize this one time offset of 44 billion tons of CO2 The average car emits about 4 tons of CO2 each year Permanently increasing the solar reflectance of urban roofs and pavements worldwide would offset 11 billion car years of emission This 1s equivalent to taking the world s approximately 600 million cars off the road for 18 years If roofs were changed from their current dark colors to Duration of Annual CO2 Equivalent Cars Offset white for flat roofs and cool Program Offsets colors for sloped roofs we 10 Yr 2 4 Billion t yr 600 million Cars for 10 could offset 24 billion tons years of CO2 If we take 20 years 20 Yr 1 2 Billion t yr 300 Million Cars for 20 to implement just the cool years roofs portion it s the equivalent of taking half of the cars in the world off the road for every year of the 20 year program see table The offset provided by cooling urban surfaces affords us a significant delay in
125. e distance from the window to the farthest most edge of the overhang and dividing that by the distance from the bottom of the window to the lowest point of the overhang Error Reference source not found demonstrates how to calculate a projection factor Projection Factor H horizontal V vertical The ECBC provides a modified SHGC requirement where there are overhangs and or side fins which are a permanent part of the building This may be applied in determining the SHGC for the proposed design An adjusted SHGC accounting for overhangs and or sidefins is calculated by multiplying the SHGC of the unshaded fenestration product by a multiplication M factor If this exception is applied a separate M Factor shall be determined for each orientation and unique shading condition Figure 11 Projection Calculation 44 PF Ratio of overhang projection divided by height from window sill to bottom of overhang must be permanent Solar Heat Gain Coefficient Requirements dependent on Overhang projection factor M factor from Table 4 3 3 2 Orientation AND Climate zone Without Overhang SHGC range 0 25 0 51 based on Climate zone ECBC Table 4 4 reproduced in Table 13 provides the values of M factor for various projection factors Table 13 SHGC M Factor Adjustments for Overhangs and Fins Overhang M Factors for 4 Projection Factors 0 25 0 50 0 75 1 00 0 49 ee Overhang
126. e insulated to a minimum R 1 4 R 8 value This would include for example a duct located on top of a flat roof This required R value also applies to insulation for ductwork located either unventilated attics with no roof insulation or in ventilated attics Return ducts in these three conditions must have R 0 6 R 3 5 insulation Supply ducts installed in attics with roof insulation are required to be insulated with a lower minimum R value R 0 6 R 3 5 as are ducts in interior unconditioned spaces such as both ventilated and non ventilated crawlspaces Supply ducts which are buried must also have R 0 6 R 3 5 insulation The return ducts in these three cases are not required to be insulated Any ductwork in indirectly conditioned space such as return air plenums with or without exposed roofs above is not required to be insulated Of course ductwork in conditioned space also has no insulation requirement Although not always aesthetically possible locating ductwork within conditioned space is an excellent efficiency strategy since this eliminates undesired heating ot cooling of the air in the ducts Table 22 Ductwork Insulation Ooo C E T RO C E T E S Unvented Ati witout Roof msan ea ros Unvented Atie with Roof msuaion R06 NoRequiremen Unconditioned Space ROG No Requirement Indirectly Conditioned Space No Requirement No Requirement Insulation R value is measured on a horizontal plane in accordance with ASTM
127. e of electrical equipment used to convert electric power from one voltage to another voltage U factor Thermal Transmittance heat transmission in unit time through unit area of a material or construction and the boundary air films induced by unit temperature difference between the environments on each side Units of U are W m 2 C Btu h ft2 FP Variable Air Volume VAV system HVAC system that controls the dry bulb temperature within a space by varying the volumetric flow of heated or cooled supply air to the space Vent damper a device intended for installation in the venting system or an individual automatically operated fossil fuel fired appliance in the outlet or downstream of the appliance draft control device which is designed to automatically open the venting system when the appliance is in operation and to automatically close off the venting system when the appliance is in standby or shutdown condition Ventilation the process of supplying or removing air by natural or mechanical means to or from any space Such air is not required to have been conditioned Visible Light Transmittance VLT Also known as the Visible Transmittance is an optical property of a light transmitting material e g window glazing translucent sheet etc that indicates the amount of visible light transmitted of the total incident light Wall that portion of the building envelope including opaque area and fenestration that is vertical or tilted
128. e requires that power cabling be adequately sized as to maintain the distribution losses to not exceed 1 of the total power usage Maintenance of a record of the design calculation for the losses is also specified An engineer or contractor can demonstrate the real savings as well as the advantages of lower generated heat and increased flexibility of the installation with a properly sized distribution system In addition when less heat is generated the result is reduced energy requirements for fans and air conditioning systems 116 9 ENERGY SIMULATION 9 1 GENERAL To show that a building is ECBC compliant using whole building performance a building energy simulation model using a standard design and a proposed design needs to be developed The results of these simulations are compared to see whether the proposed design is more efficient than standard design and ECBC compliant or not All this process of preparing the standard design model and the proposed case model is explained in this section using a case study This case study includes the step by step procedures followed for an example building located in GandhiNagar Gujarat India The steps involved for ECBC compliance of any building are e Confirmation from the local authority e Comply with the Mandatory Requirements of the ECBC e Create the standard design simulation model e Create the proposed case design simulation model e Comparing the results from the two models e
129. echnologies The ECBC and energy efficient building design can help the building owners and facility managers not only aim to reduce operating costs but can also contribute towards increasing the reliability and availability of electricity improve building occupant comfort reduce environment degradation and help the flight against global warming by lowering greenhouse gas emissions We have designed the User Guide to be modular and easily expandable We encourage feedback which will help us improve its usability Development Team COMPARISON OF INTERNATIONAL BUILDING ENERGY STANDARDS Prepared by Meredydd Evans and Bin Shui Pacific Northwest National Laboratory With support from the U S Department of Energy Buildings account for about 1 3 of all the energy consumption in the world and much of this consumption footprint is locked in through the design and construction of the building 1 Building energy standards are an important tool to improve energy efficiency in new buildings For example China s residential energy standard requires new buildings to be 65 more efficient than buildings from the early 1980s In the U S building energy codes2 save over 1 billion in energy costs per year and this figure is growing 3 Denmark adopted one of the first comptehensive building energy codes in 1961 and it has seen average household energy consumption per unit of space drop substantially since then 4 Building energy standards set requirem
130. ecorative lighting that is purely ornamental and installed for aesthetic effect Decorative lighting shall not include general lighting Lighting emergency lighting that provides illumination only when there is a general lighting failure Lighting general lighting that provides a substantially uniform level of illumination throughout an area General lighting shall not include decorative lighting or lighting that provides a dissimilar level of illumination to serve a specialized application or feature within such area Lighting Efficacy LE the quotient of the total lumens emitted from a lamp or lamp ballast combination divided by the watts of input power expressed in lumens per watt Lighting system a group of luminaires circuited or controlled to perform a specific function Lighting power allowance Interior lighting power allowance the maximum lighting power in watts allowed for the interior of a building Exterior lighting power allowance the maximum lighting power in watts allowed for the exterior of a building Lighting Power Density LPD the maximum lighting power per unit of area of a building classification of space function Low rise residential single family houses multi family structures of three stories or fewer above grade manufactured houses mobile homes and manufactured houses modular Lumen It is the unit of total light output from a light source If a lamp or fixture were surrounded by a transpare
131. ected system cooling load at outside air temperatures of 10 C 50 F dry bulb 7 2 C 45 F wet bulb and below In other words under the right conditions an economizer must be able to switch a system over so that all of the design supply air is supplied by outside air Figure 16 The Components of an Economizer Key Air Information FI a OW Flow Qutdoor Temperature Logic Controller _ Heating __ Coil __ Cooling Coil Outside Air Mim SA A s Su Air oe a PPY Matori mt ON lt Actua or Patina AN F damper Ue Ge Motorized Source E Source Cooling Atlas FAQs 13 Air Economizer What is an Air Economizer An air economizer is duct and damper arrangement and automatic control system that together allow a cooling system to supply outdoor air to reduce or eliminate the need for mechanical cooling during mild or cold weather Air Supply Economizer Diagram 100 Outside Air Economizer Operation ar 100 Exhaust Outside Air Dampers are fully open Maximum outside alr Is provided Minimum Supply f of Outside Alr a gt 55F Narmal Operation E Qutside Air Dampers are Pasitianed provide the minimum outside Air t What is a Water Economizer A water economizer is a system by which the supply air of a cooling system is cooled indirectly with water that is itself cooled by heat or mass transfer to the environment without the use of mechanical cooling Water Supply Economizer Dia
132. ed floor area is 1 000 m 10 000 ft or greater and or the building has a connected load of 500 kW or a contract demand of 600 kVA or greater Also when space conditioning for the addition is provided by existing systems and equipment those existing systems and equipment do not need to comply with the code Any new equipment installed must comply with specific requirements of the ECBC as listed in Table 1 Compliance can be demonstrated for the addition alone or for the addition together with the entire existing building If meeting compliance for the addition alone mandatory and prescriptive requirements must be followed with the exception of existing space conditioning systems as noted above If demonstrating compliance for the existing building and addition together either the Prescriptive or Whole Building Performance method may be used as if it were a new building If following the whole building approach trade offs can be made between the addition and improvements to the existing building so that the annual energy cost of the existing building plus the proposed addition is less than the existing building plus an addition that exactly meets prescriptive requirements While the envelope might not meet the prescriptive requirements other systems such as lighting might be improved using this existing building plus addition approach Table 1 Equipment Requirements for Building Additions An existing central plant will provide hot and Th
133. eer ee 71 JA Prcsenpuvye Regue meni srno n nar a E i E EE ETEA T2 k Ne MOA E oro E A E E EE EE 73 Boe Vatiable Flow Hydronic Systems saan sa tecc centr cues artes tear tiaseaene restate pesca 7 6 SERVICE WATER HEATING AND PUMPING See 81 6 1 OS eee adc rns cera athe E AA EN E O A E A A E E eadenasts S1 6 2 Man aoa RE a A E E E EN 81 e O hes eal Fecha N Re E mere eer nr A A A 81 10 11 12 13 G22 BEaumment EEN Cle Mey asic i ciacacateses sea cedovstearacvomatedsiuinara N 83 O25 Supplementary Water Heatine System aisinn ern E E EOE 86 Gat Apne InGulat Oi saen a T E E 86 Oae AA SBS 0 nme rere eee OP Te CaP CeTT PRATT ED On PERRET E PN RL ry Oe ener ey re 88 O2 SAS cl vabagibalcap 2 616 serene cement ar mn meen Cn reac tare mre me err EO 89 Gal AeOmaplianee De Grier 2 ON aati sai a site Sns Ste aa a teal ve esha leans E 89 LIGHTING Come rere re rer er erences ere ee sere sees ese sede ees es eee sD EHD EEE HEE eH EHO EEE EEE ED OLED Ede rere reresene 90 7 1 SC Ba ait hi ahora ssn sca bal a bese T T E eben aonsemsa eens 90 T2 Mandatory Regate Mi Soria na a E E ATE 92 Tal Leitis GonTohanraeisriin a A a cy ener er rere ree 92 nk EO DS sasha sucess hc aisha E EOS 97 Ga Exterior Buildin Grounds 1th Sgro ss soe rir E i eens ata T 98 ka PEESCTD EV Clk COU KONIE S a E A E E N TO 98 Tok TETO ELON PON T rap 98 Roia Buldim Area MeO asinna ean ne EEIE O ECT 100 To pace Pumehor Wet iniinis saie E E E E A 101 ow dasaled Interior Lonin Powe
134. el to the plane of the face of the building Non horizontal roof surfaces shall be included in the calculations of vertical fa ade area by measuring the area in a plane parallel to the surface Fan system power the sum of the nominal power demand nameplate W or HP of motors of all fans that are required to operate at design conditions to supply air from the heating or cooling source to the conditioned space s and return it to the source of exhaust it to the outdoors Fenestration all areas including the frames in the building envelope that let in light including windows plastic panels clerestories skylights glass doors that are more than one half glass and glass block walls Skylight a fenestration surface having a slope of less than 60 degrees from the horizontal plane Other fenestration even if mounted on the roof of a building is considered vertical fenestration Vertical fenestration all fenestration other than skylights Trombe wall assemblies where glazing is installed within 300 mm 12 in of a mass wall are considered walls not fenestration Fenestration area total area of the fenestration measured using the rough opening and including the glazing sash and frame For doors where the glazed vision area is less than 50 of the door area the fenestration area is the glazed vision area For all other doors the fenestration area is the door area Floor area gross the sum of the floor areas of the spaces within the buil
135. element It indicates the total amount of heat transmitted from outdoor ambient to indoor ambient through a given wall or roof per unit area per unit time The lower the U value the higher is the insulating value of the element Thus the U value can be used for comparing the insulating values of various building elements It is calculated as follows osha viciavindsaentadvavecernnnss 1 3 Whetre Rr is the total thermal resistance and is given by Ea a E 1 4 Or ERa rA A Se ee eee 1 4 ii hj and ho respectively are the inside and outside heat transfer coefficients and are measured in W m K hi and ho are due to convection heat transfer between solid surfaces and inside and outside air These are also commonly referred to as film conductance or U Value of air films outside and inside Surface conductance and resistances for air is given in below in Table 1 0 47 and Lj is the thickness of the j layer and kj is the thermal conductivity of its material Table 1 0 Surface Conductances and Resistances for Air Surface Emittance Non a reflective Reflective Position of of Heat g 0 90 g 0 20 e 0 05 Surface Flow h R h R h R STILL AIR Horizontal Upward 9 26 0 11 5 17 0 19 4 32 0 23 Sloping 45 Upward 9 09 0 11 5 00 0 20 4 15 0 24 Vertical Horizontal 8 29 0 12 4 20 0 24 3 35 0 30 Sloping 45 Downward 7 50 0 13 3 41 0 29 2 56 0 39 Horizontal Downward 6 13 0 16 2 10 0 48 1 25 0 80 MOVING AIR Any posi
136. ency of individual elements in the envelope or 2 Trading off the efficiency of one envelope element for another with a resulting envelope system that achieves the level of efficiency required by the code The envelope trade off equation is found in Section 12 Appendix D of ECBC Whole Building Performance Approach Use of energy simulation software is necessary to show ECBC compliance via the Whole Building Performance Method Energy simulation is a computer based analytical process that helps building owners and designers to evaluate the energy performance of a building and make it more energy efficient by making necessary modifications in the design before the building is constructed These computer based energy simulation programs model the thermal visual ventilation and other energy consuming processes taking place within the building to predict its energy performance The simulation program takes into account the building geometry and orientation building materials building facade design and characteristics weather parameters indoor environmental conditions occupant activities and schedules HVAC and lighting system and other parameters to analyze and predict the energy performance of the buildings Computer simulation of energy use can be accomplished with a variety of computer software tools and in many cases may be the best method for guiding a building project to be energy efficient 10 However this approach does require
137. energy efficient provide improved thermal comfort extend the life of the building equipment and reduce the cost of operating it Balancing is achieved by optimizing the air water distribution rates for the HVAC system Air System Balancing Adjusting airflow rates through air distribution system devices such as fans and diffusers by manually adjusting the position of dampers splitter vanes extractors etc ot by using automatic control devices such as constant air volume or variable air volume boxes Hydronic System Balancing Adjusting water flow rates through hydronic distribution system devices such as pumps and coils by manually adjusting the position of valves or by using automatic control devices such as flow control valves 69 The ECBC requirements do not dictate a specific way in achieve a balanced HVAC system but they do require that all systems be balanced in accordance with generally accepted engineering standards In turn the construction documents must require that a written balance report be provided to the owner or the designated representative of the building owner for HVAC systems serving zones with a total conditioned area exceeding 500 m2 5 000 ft2 ECBC 5 2 5 1 Specific strategies for balancing air systems and hydronic systems are also required to be followed as described below FAQ 10 System Balancing What does it mean when a system is balanced When something is balanced it is even on both sides ev
138. ental ingress of moisture to diffuse as Vapor The exception to this would be in installations where the interior temperature and humidity are expected to be significantly higher than those on the outside Source DuPont Correct Typical Opaque Exterior Wall Constructions Metal framed walls Many commercial buildings and high rise residential buildings require non combustible construction this is achieved with metal framed walls Often metal framed walls are not structural and are used as infill panels in rigid framed steel or concrete buildings The U factor criteria are higher for metal framed walls compared to wood framed walls because the metal framing members are more conductive Metal building walls Metal building walls consist of a metal building skin that is directly attached to metal framing members The framing members are typically positioned in a horizontal direction and spaced at about 4 ft A typical method of insulating metal buildings walls is to drape the insulation over the horizontal framing members and to compress the insulation when the metal exterior panel is installed Low mass walls Low mass walls have a heat capacity HC greater or equal to 0 04 but less than 0 085 kWh C m See the definition below for heat capacity Various heat capacity data exists for hollow unit masonry walls solid unit masonry and concrete walls and concrete sandwich panels High mass walls These walls have an HC equal to or greate
139. ents for how energy efficient a building will be Standards vary quite a bit between countries in several respects including the extent of their coverage the specific requirements means of attaining compliance and the enforcement system This summary provides an overview of some key trends in building energy standards and what this may mean for India Extent of Coverage Building energy standards at a minimum usually cover insulation and thermal and solar properties of the building envelope the walls roofs windows and other points where the interior and exterior of a building interface Most standards also cover heating ventilation and air conditioning hot water supply systems lighting and electrical power Some cover additional issues such as the use of natural ventilation and renewable energy and building maintenance In some countries not all the issues are considered in a single standard For example the Chinese standards include lighting in a separate document Within these broad categories there are also numerous differences in what the specific requirements cover Some countries have significant detail about the need to minimize condensation on insulation Some countries like India or Japan have detailed requirements based on different types sizes or orientations of buildings for example while others have simpler requirements for a broader range of buildings The U S India and Canada all have commercial building energy codes der
140. er is selected from Table 5 1 of Section 5 2 2 of the code Since some of the values given in this table are aspirational values these specific values will be followed as in ASHRAE 90 1 2004 CXXII For this case study building in Gujarat since the sizing run gave XXX TR as chiller capacity the COP of the chiller in the standard design model will be 6 1 Any other values or details of the HVAC would be as specified in Table 10 1 and Table 10 2 of Appendix B Any values which are not specified by the code will be followed from ASHRAE 90 1 2004 Appendix G All the values which both ECBC and ASHRAE 90 1 2004 are silent about will be as modeled same as in the proposed case model 9 2 4 Step 4 Create the Proposed design Simulation Model The proposed design simulation model captures all the features of the proposed design The building simulation model should appropriately incorporate all the energy related features of the proposed building design Certain approximations in creating the geometry of the model are allowed However with the available information within the available time and with the minimum number of approximations the most accurate model is to be prepared by selected software which has all features as specified by the code The selection of the software should be done based on the specification of the code as in Section 10 2 1 of Appendix B All the allowed types of approximations are explained within the code itself 9 2 4
141. ergy use in variable flow systems limit the use of three way valves to one or two to prevent pump dead heading Example taken from ASHRAE 90 1 2004 User Guide Variable speed drives Variable speed drives are required to control chilled water and condenser water systems that have pump motors greater than or equal to 3 7 kW 5 hp 5 3 2 1 XXX 5 3 2 2 XXX 5 3 2 3 XXX HVAC EQUIPMENT FOR ENERGY CONSERVATION Heat Recovery Systems A common energy conservation opportunity is that of to utilize the heat transfer between various components of the HVAC system The following are the some of the available strategies and equipments Boiler Economizers These achieve heat transfer by passing the hot gases in a boiler s stack through a heat exchanger thus preheating the incoming boiler water as a energy conservation strategy Runaround Coils These can be used for heat transfer between intake and exhaust air ducts Heat transfer between incoming and exhaust air streams through heat pipes heat transfer wheels and desiccant systems can play major roles in energy conservation Economizer Cycles These use cool outdoor air when available to ease the burden on a refrigerant cycle as it cools the re circulated indoor air See section 5 3 1 Geo Exchange Systems These ground source heating and cooling GSHC technologies use the earth or available water bodies as a heat source or heat sink for buildings Geo exchange technology transfers he
142. erything is equal Therefore a balanced hydronic system is one that delivers even flow to all of the devices on that piping system Each component has an effective equal length of pipe on the supply and return And when a system is balanced all of the pressure drops are correct for the devices When that happens you have the highest efficiencies possible in that system You do not need to change your system supply temperatures to accommodate one zone only The system has the least amount of pressure drop possible which translates into reduced pumping costs A balanced hydronic system is one that is efficient If you have a system that is not delivering 5 2 5 1 1 Air Systems Balancing is necessary to verify that each space served by a system receives the air volume designed for that space A means for air balancing should be installed at each supply air outlet and zone terminal device This includes balancing dampers or other means of supply air adjustment provided in the branch ducts or at each individual duct register grille or diffuser Installation in the duct system of all devices used for balancing shown on the approved mechanical plans typically on the ductwork layout should be verified The requirements state that air systems must first be balanced in a manner to minimize throttling losses For fans greater than 0 75 KW 1 0 HP fans must then be adjusted to meet design flow conditions ECBC 5 2 5 1 1 5 2 5 1 2 Hydronic Systems
143. es Increase surface Increase surface reflectivity Pale colour glazed china mosaic tiles etc Promote Heat Loss Ventilation of appliances Provide windows exhausts Increase air exchange rate Ventilation during night time Courtyards wind towers arrangement of openings Increase humidity levels Trees water ponds evaporative cooling Thermal Requirements Physical Manifestation Resist Heat Gain CY Rete surace ofroof OOOO Walls glass surfaces protected by overhangs fins Increase shading and trees Increase surface reflectivity Pale colour glazed china mosaic tiles etc Promote Heat Loss Ventilation of appliances Provide windows exhausts Increase air exchange rate Ventilation Ventilated roof construction Courtyards wind throughout the day towers and arrangement of openings Decrease humidity levels Dehumidifiers desiccant cooling Thermal Requirements Physical Manifestation Resist Heat Gain Decrease exposed surface area g Orientation and shape of building 18 Increase thermal resistance Roof insulation and east and west wall insulation East and west walls glass surfaces protected by Increase shading overhangs fins and trees Increase surface reflectivity Pale colour glazed china mosaic tiles etc Promote Heat Loss Ventilation of appliances Provide windows exhausts Provide windows exhausts Increase air exchange rate Ventilation Courtyards and arrangement of openings Decrease exposed surfa
144. es vertical fenestration in walls with an effective aperture greater than 0 06 6 The daylighted area extends into the space perpendicular to the side aperture a distance either two times the head height of the side aperture or to the nearest 1 35 m 54 in ot higher opaque partition whichever is less In the direction parallel to the window the daylighted area extends a horizontal dimension equal to the width of the window plus either 1 m 3 3 ft on each side of the aperture the distance to an opaque partition or one half the distance to an adjacent skylight or window whichever is least Dead band the range of values within which a sensed variable can vary without initiating a change in the controlled process Demand the highest amount of power average Btu h over an interval recorded for a building or facility in a selected time frame Design capacity output capacity of a system or piece of equipment at design conditions Design conditions specified environmental conditions such as temperature and light intensity required to be produced and maintained by a system and under which the system must operate Distribution system a device or group of devices or other means by which the conductors of a circuit can be disconnected from their source of supply Door all operable opening areas which are not fenestration in the building envelope including swinging and roll up doors fire doors and access hatches Doors that are more
145. es for a given circuit the rate at which electric energy is converted into heat or radiant energy and that has a value such that the product of the resistance and the square of the current gives the rate of conversion of energy Reset automatic adjustment of the controller set point to a higher or lower value Residential spaces in buildings used primarily for living and sleeping Residential spaces include but are not limited to dwelling units hotel motel guest rooms dormitories nursing homes patient rooms in hospitals lodging houses fraternity sorority houses hostels prisons and fire stations Return Air Air from the conditioned area that is returned to the conditioning equipment for reconditioning The air may return to the system through a series of ducts plenums and airshafts Roof the upper portion of the building envelope including opaque areas and fenestration that is horizontal or tilted at an angle of less than 60 from horizontal Roof area gross the area of the roof measured from the exterior faces of walls or from the centerline of party walls Service the equipment for delivering energy from the supply or distribution system to the premises served Service water heating heating water for domestic or commercial purposes other than space heating and process requirements Set point point at which the desired temperature C of the heated or cooled space is set Shading Coefficient SC the ratio of solar heat
146. es to providing this flexibility In many countries including India the U S Canada and Australia the codes have four classes of requirements The first are mandatory requirements that must be satisfied regardless of any other factors for a building to be considered in compliance The majority of these codes are then made of up prescriptive requirements which are similar to the mandatory requirements in that they provide specific values and details However building designers may be allowed to trade off some of the prescriptive requirements with others regarding the building envelope The codes then provide rules on what can be traded off and how Finally these codes also provide an option for compliance based on building energy performance instead of the prescriptive requirements This last option would allow a building designer to install less efficient windows but a mote efficient air conditioning system if the total designed energy use falls within the required norms There are several approaches to establishing the baseline for comparison under the building energy performance method The UK uses a total carbon footprint of the building called the Carbon Index Rating 5 the U S uses the cost as its reference metric while some other countries define the characteristics of a reference building for the comparison Korea takes a different approach establishing mandatory requirements and points for a whole range of energy issues related to
147. estration Overall Assembly including the Sash and Frame EXAMPLE 6 Estimate a representative U factor for a wood framed 970 by 2080 mm swinging French door with eight 280 by 400 mm panes true divided panels each consisting of clear double glazing with a 6 5 mm air space and a metal spacer SOLUTION 6 Without more detailed information assume that the dividers have the same U factor as the frame and that the divider edge has the same U factor as the edge of glass Calculate the center of glass edge of glass and frame areas Ag 8 280 130 400 130 10 0 324 m2 Ag 8 280 x 400 10 0 324 0 572 m 970 x 2080 106 8 280 x 400 106 1 122 m Select the center of glass edge of glass and frame U factors These component U factors are 3 12 and 3 63 W m2K from Chapter 25 Table 4 ASHRAE Fundamentals 2005 glazing ID 4 U factor columns 1 and 2 and 2 90 W m2 K from Chapter 25 Table 4 ASHRAE Fundamentals 2005 wood frame metal spacer operable double glazing respectively From Equation 1 19 _ 3 12 0 324 3 63 0572 2 90 1 122 EUS ZU 3 14 W m2k be 12 1 8 Estimation of Heat Transfer Through Computer Based Tools The above examples are simple illustrations of the steady state calculation of heat gain or loss for individual building elements or a single zone conditioned building The method can also be extended to multi zone or multi storeyed buildings but
148. etetstesssssssetertesnsssssserrrreesssree 36 Table 5 Opaque Wall Assembly U Factor and Insulation R Value Requirements eerreersrrreesrsrreeeersreeerrsrrerersreeerrsreeess 33 AE S E L TE 1 TAE A E EAE 37 Table 7 Thermal Properties of Commonly Used Construction Materials in India seeesesreeessrereeessrreessssreeerrsrreeersereeeee 39 Table 8 Thermo Physical Properties of Various Thermal Insulating Materials eeseerresseereesssrreeeesssreeersrreeesrrreeeeseresenees 40 Table 9 Vertical Fenestration U Factor and SHGOC Requiremientavastssssassesssocassdevosesancaoassonnsaorsssnnssonnooessannuanuroaniveans 40 Table 10 Defaults for Unrated Vertical Fenestration Overall Assembly including Sash and Frame eee eees 4 Theil ample ea oaea een mali eE ERER 42 Table 12 Performance and Cost Estimates for Glazing Products sssssssrsssreeessessssseseeeeeersssseeeeeeesrsreeeeeerersssrerereeeeeeeeesse 42 Table 13 SHGC M Factor Adjustments for Overhangs and FinS ssssssesrrereererrteeeeteesrsesssssssssssssssssssstetetreereeeesssreees 44 Table T4 Manimniiay VET Requmementynnienneanmeenaiemicaranie EE nanan 50 Table 15 Skylight UFactor and SUGC Reguinermen tsncsesaeshaesonsptaasesancastacsnsvearearan Ea elekea 53 abe leOn alada A E ea E areca eee eee 6 Table 17 Enerey Savings Potential in HVAC System D signis vssiwsisorossoviesssesioornsononsessinsanasvenosvenaseaeraesensevensaannss 61 Table 18 Power Consumption Ratings for Unitary Air Conditioner
149. f utmost importance when meeting the fenestration requirements U values for fenestration products including the sash and frame are required to be determined in accordance with ISO 15099 as specified in ECBC Section 11 Appendix C by an accredited independently laboratory and labeled and certified by the manufacturer or other responsible party In the U S the fenestration U values are determined in accordance with the National Fenestration Rating Council NFRC Standard 100 NFRC is a membership organization of window manufacturers researchers and others that develops supports and maintains fenestration rating and labeling procedures Most fenestration manufacturers have their products rated and labeled through the NFRC program Certified products receive an 8 2 by 11 inch NERC label that lists the U factor SHGC visible transmittance the project address the number of these fenestration products to be installed in the building project the frame material supplier the glazing material supplier the glazing contractor and the certification authorization 21 4 2 1 2 SHGC There is a complex relationship between these three characteristics of fenestration systems See Figure 6 ECBC requires U factor and Solar Heat Gain Coefficient SHGC to be determined for all fenestration products by the manufacturer or other responsible party ECBC 4 2 1 1 and 4 2 1 2 The SHGC indicates how well the product insulates against heat caused by sun f
150. faces W G Stefan Boltzmann constant 5 67x108 W m2 K 4 A area of surface m7 T temperature of surface 1 K T2 temperature of surface 2 K e1 and e2 emissivities of surfaces 1 and 2 respectively In case of buildings external surfaces such as walls and roofs are always exposed to the atmosphere So the radiation exchange Qa between the exposed parts of the building and the atmosphere is an important factor and is given by Graa ABET Tote eee 1 14 Where A area of the building exposed surface mz e emissivity of the building exposed surface T temperature of the building exposed surface K T sky sky temperature K Tsky represents the temperature of an equivalent atmosphere It considers the fact that the atmosphere is not at a uniform temperature and that the atmosphere radiates only in certain wavelengths There are many correlations suggested for expressing sky temperature in terms of ambient air temperature Equation 1 14 can be written as Rll Ta t OAR eee 1 15 Where T ambient temperature K CLX is the radiative heat transfer coefficient and AR is the difference between the long wavelength radiation incident on the surface from the sky and the surroundings and the radiation emitted by a black body at ambient temperature For horizontal surface AR can be taken as 63 W m and for a vertical surface it is Zero 12 1 5 Solar Heat Gain The solar gain throu
151. factor correction devices e Electric check metering and monitoring system details 13 4 BUILDING ENVELOPE 4 1 GENERAL Overview his chapter describes requirements for the design of commercial building envelopes The building envelope refers to the exterior facade and is comprised of walls windows roof skylights doors and other openings Building envelopes consist of opaque components and fenestration components Opaque envelope components include walls roofs floors floor slabs basement walls and opaque doors See Figure 3 Fenestration components include windows skylights ventilators and doors that are more than one half glazed This enclosure protects the building s interior and occupants from the weather conditions and other external elements While the envelope does not directly use energy its design features strongly affect the visual and thermal comfort of the occupants as well as energy consumption in the building The design of the building envelope is generally the responsibility of an architect and occasionally of an engineer The designer is responsible for making sure that the building envelope complies with the code This chapter is written for the designer as well as other specialists who participate in the design and construction of the building envelope Figure 3 Building Envelope Envelope Design Considerations The building envelope is one of the most important factors in designing energy efficient
152. fically the code requires the following areas of the enclosed building envelope to be sealed caulked gasketed or weather stripped to minimize air leakage e joints around fenestration and door frames e Openings between walls and foundations and between walls and roof and wall panels 25 e Openings at penetrations of utility services through roofs walls and floors e Site built fenestration and doors e Building assemblies used as ducts or plenums e All other openings in the building envelope The Code specifies air leakage for glazed swinging entrance doors and revolving doors shall not exceed 5 0 1 s m2 Air leakage for other fenestration and doors shall not exceed 2 0 1 s m2 As with all of the mandatory requirements the air leakage requirements must be met with all compliance approaches even the Whole Building Performance method 4 33 PRESCRIPTIVE REQUIREMENTS For this component based compliance approach ECBC sets requirements for e Exterior Roofs and Ceilings e Opaque walls e Vertical fenestration and e Skylights Roofs and opaque walls can either meet maximum U factors for assemblies or minimum R factors for the insulation only ECBC 4 3 1 and 4 3 2 The requirements are climate based and different for buildings used only during the day such as offices from those used 24 hours such as hospitals ECBC Appendix D provides values for typical constructions If designing a cool roof requirements for minimum solar
153. fied in the code The lighting power should include the power consumed by ballasts as well as the lamps The lighting system power in the simulation model should include all lighting system components shown or provided for on plans including lamps ballasts task fixtures and furniture mounted fixtures This building in Gandhinagar has an LPD value of 8 61 W m2K in the office areas and 1 61 W m2K in the parking areas There are no daylight sensors proposed in the design the lighting systems for this building However in cases where the electrical design for the proposed building included lighting controls they should be included in the simulation model 9 2 4 3 HVAC The HVAC system in the proposed design simulation model should be specified according to the suggested mechanical design layout All the inputs should be as per the designs which include the fan and equipment efficiencies static pressure pump heads etc None of the default values by the software should be considered as the input values for these parameters of HVAC The office building is served by a VAV handling unit which is served by a centrifugal chiller Since the internal HVAC design and zoning of the proposed building is not yet done a perimeter and core zone model with simplified zoning is considered in both the proposed and standard design simulation models In cases where the HVAC zoning is not designed the code suggests that a simple zoning is to be done such that the c
154. g controls when weather conditions permit or when facilities are unoccupied Adjust air supply from the air handling unit to match the required space conditioning Eliminate reheating for humidity control often air is cooled to dewpoint to remove moisture then is reheated to desired temperature and humidity 5 Install an economizer cycle Instead of operating on a fixed minimum airflow supply an economizer allows the HVAC system to utilize outdoor air by varying the supply airflow according to outdoor air conditions usually using an outdoor dry bulb temperature sensor or return air enthalpy enthalpy switchover Enthalpy switchover is more efficient because it is based on the true heat content of the air 78 6 Employ heat recovery A heat exchanger transfers heat from one medium to another Common types of heat exchangers are rotary sealed plate coil run around system and hot oil recovery system Install heat recovery ventilators that exchange between 50 and 70 percent of the energy between the incoming fresh air and the outgoing return conditioned air 7 Minimize the amount of air delivered to conditioned space The amount of air delivered to a space is dependent upon heating cooling load delivery temperature ventilation requirements and or air circulation or air changes On average the air should change every five to 10 minutes Reducing airflow will reduce horsepower Extend the time frame for circulation of air by using a fan dis
155. g of the glazing In the standard design the glazing WWR is spread on all the facades equally as specified in Table 10 1 4 of Appendix B In this base line building there is no self shading of the building allowed as specified in Table 10 1 4 of Appendix B No assumed efficiency measures should be modeled over the proposed design to meet the standard design or to perform better than standard design However efficiency options designed for implementation in the proposed building can be included in the proposed design simulation model 9 2 5 Step 5 Completing and comparing the models Both the proposed design model and the standard design simulation models are run and the results are analyzed to check for errors In some cases there are unmet hours generated which state the hours in a year which are of discomfort either due to cooling or the heating They are normally categorized either as the system unmet or the plant unmet hours which state the number of hours either the system or the plant was unable to meet the loads on them respectively This is commonly found in morning start up situations where the pick up loads cannot be met in a single hour If the number of hours that loads are unmet by either the systems or plant differs by more than 50 hours between the standard design and proposed design models these simulation results will not be accepted as valid The best way to deal with this problem is to confirm that the sizing method of both the sta
156. gain at normal incidence through glazing to that occurring through 3 mm 1 8 in thick clear double strength glass Shading coefficient as used herein does not include interior exterior or integral shading devices Simulation program a computer program that is capable of simulating the energy performance of building systems Single zone system an HVAC system serving a single HVAC zone Site recovered energy waste energy recovered at the building site that is used to offset consumption of purchased fuel or electrical energy supplies Skylight roof ratio SRR is the ratio of the total skylight area of the roof measured to the outside of the frame to the gross exterior roof Slab on grade floor that portion of a slab floor of the building envelope that is in contact with ground and that is either above grade or is less than or equal to 24 in below the final elevation of the nearest exterior orade Solar energy source source of thermal chemical or electrical energy derived from direction conversion of incident solar radiation at the building site Solar Heat Gain Coefficient SHGC the ratio of the solar heat gain entering the space through the fenestration area to the incident solar radiation typically ranging from 0 9 to 0 1 where lower values indicate lower solar gain Solar heat gain includes directly transmitted solar heat and absorbed solar radiation which is then reradiated conducted or convected into the space Space
157. gh transparent elements like glazing and skylights does not depend on the R values U Values of the surfaces but other properties like the absorptivity of the space and transmissivity of the transparent element Thus the solar heat gain through transparent surfaces can be written as a i bad LAST E E E E E E E E ET 1 17 Where a mean absorptivity of the space Aj area of the it transparent element m7 Soi daily average value of solar radiation including the effect of shading on the it transparent element W m transmissivity of the ith transparent element M number of transparent elements Fenestration solar heat gain has two components The quantity of directly transmitted solar radiation is governed by the solar transmittance of the glazing system As shown in equation 1 17 multiplying the incident irradiance by the glazing area and its solar transmittance yields the solar heat entering the fenestration directly Absorbed solar radiation is removed from the main beam and is absorbed in the glazing and framing materials of the window and some is subsequently conducted to the interior of the building EXAMPLE 3 Estimate the directly transmitted solar radiation through a single glazed window 1 5m X 3m on the south wall of a room that is maintained at 23 3 C by an air conditioner Daily average solar radiation on south wall 111 3 W m Absorptivity of glazing for solar radiation 0 06 Transmissivity of wind
158. given in horsepower Output power for motors manufactured in other countries may be stated in watts or kilowatts One horsepower is equivalent to 746 watts The ECBC requires that permanently wired motors gt 0 375 kW expected to operate more than 1 500 and motors gt 50 kW expected to operate more than 500 hours per year must have a minimum acceptable nominal full load motor efficiency not less than IS 12615 for efficient motors 107 The ECBC also requires that motor horsepower ratings do not exceed 200 of the calculated maximum load being served and that motor nameplates list the nominal full load motor efficiencies and the full load power factor Motor users should insist on proper rewinding practices for any rewound motor If proper rewinding practices cannot be assured the damaged motor should be replaced with a new efficient motor The EBCB requires that certificates be obtained for rewound motors indicating motor efficiency After rewinding a new efficiency test shall be performed and a record maintained Table 33 Energy Efficiency Measures for Motors and Benefits Motors Better efficiency and power factor over load range Cooler operation Replace standard Efficiency motors with premium P efficiency motors Potentially longer life Corrects for previous damage from rewinds and aging Higher tolerance to voltage unbalance and fluctuations overload harmonics heat _ Improved power factor Correct motors over sizing to
159. gram Can I take advantage of cool outside air to pre cool my building Yes use the buildings intrinsic thermal mass to reduce peak cooling loads by circulating cool nighttime air to pre cool the building prior to daily occupancy in the cooling season The building control system can operate ventilation fans in the economizer mood on a scheduled basis Care should be taken to prevent excessive fan operation that would offset cooling energy savings Also be sure that night humidity does not preclude the use of this strategy 74 Exemptions e Projects in hot dry and warm humid climates 5 3 1 2 Individual ceiling mounted fan systems lt 3 200 1 s 6 500 cfm Partial cooling In addition to providing cooling with 100 outside air economizers must also be capable of providing partial cooling So when conditions require it although additional mechanical cooling is needed the economizer can assist in meeting the cooling load Testing All air side economizers shall be tested in the field to ensure proper operation following the requirements in ECBC Section 14 Appendix F Air Side Economizer Acceptance Procedures Envelope Summary An exception is allowed if an air side economizer is installed by a HVAC system equipment manufacturer and is certified to the building department as being factory calibrated and tested per the procedures in ECBC Section 15 Appendix G Compliance Forms Economizer Testing Procedure Step 1 Simulation a coo
160. graphy Hilly or high plateau region with abundant vegetation Moderate summer temperatures and very low in winter Low humidity in cold sunny and high humidity in cold cloudy Low precipitation in cold sunny and high in cold cloudy High solar radiation in cold sunny and low in cold cloudy Cold winds in winter Very little vegetation in cold sunny and abundant vegetation in cold cloudy This applies when 6 months or more do not fall within any of the above categories High temperature in summer and cold in winter Low humidity in summer and high in monsoons High direct solar radiation in all seasons except monsoons high diffused radiation Occasional hazy sky Hot winds in summer cold winds in winter and strong wind in monsoons Variable landscape and seasonal vegetation 17 to 24 20 to 30 32 to 43 27 to 32 10 to 25 25 to 25 5 to 15 35 to 22 Variable Dry Periods 20 50 Wet Periods 50 95 Low lt 200 mm yr Moderate 1000mm yr Variable 500 1300 mm yr during monsoon reaching 250 mm in the wettest month Clear with cloud cover lt 50 Overcast for most of the year Variable Overcast and dull in the monsoon Jammu amp Kashmir Ladakh Himachal Pradesh Uttaranchal Sikkim Arunachal Pradesh Uttar Pradesh Haryana Punjab Bihar Jharkhand Chattisgarh Madhya Pradesh etc CXLVIII Sources Bansal and Minke 1988 Clim
161. h modifications can allow many stakeholders to have input into the process which in turn makes the code more feasible to implement Indian consumers could benefit from this process as the energy costs in new buildings decline at the same time that the environmental footprint of these buildings grows smaller VII TABLE OF CONTENTS ENERGY CONSERVATION BUILDING CODE ECBC USER GUIDE cvvssssttsrrrrre eee e eee eeees I ENERGY CONSERVATION BUILDING CODE ECBC USER GUIDE crvrssstrrtrrrrrre steerer eeeee 4 1 PURPOSE Cee ere ce rere reser er eee reser ee ee ses eee see eee Eee E see SEDO EE DEDEDE DELO DERE E DEDEDE DEDEDE EEE EEEDEEeeE 2 2 SCOPE soir wns EE E E 4 Zd Applicable Pudding oya OS aeon enie EEA rar en EEEN EEE A 4 22 TEP OMI S A A N E E E san it ats seca coerce nach seat crue T E E A reasons 4 22 Safety Health and Environmental Codes Take Precedence ee sessecseeececeeeeeceeeeeeeceaceeeeeees 4 2 4 TR GN AI etcetera eas oc sae E rm E A E A A eee 5 3 ADMINISTRATION AND ENFORCEMENT Cece cer ercrcrcsccccceccce cece ee ceeeeeereeeeeeeeseeesees 6 3 1 Oei ore Weaybth ces col csi A mmener cere E rant rer E rere rer renter ren err re 6 LE IV ACO Es IR GIS LAA NS sect ace rtp E E E O ETE eee eee nen 6 D a bil be ire saceeenereern tere cee mer r etre tre nen errr emer terme enter rst cere reer rree tere eT rere 6 Ss Maen a a ineCey ole do Existing Buildings opener mcr mite terete tra reenter re trrrnrer rere Crna a er ter rcerrrr Ts fi LF Alke
162. harge kWh savings x energy charge The above equations apply to motors operating at a specified constant load For varying loads you can apply the energy savings equation to each portion of the cycle where the load is relatively constant for an appreciable period of time The total energy savings is then the sum of the savings for each load period Determine the demand savings at the peak load point The equations are not applicable to motors operating with pulsating loads or for loads that cycle at rapidly repeating intervals Kilowatts Saved kW saved bp x Load x 0 746 x 100 Estd 100 Ehe 75 x 75 x 0 746 x 100 91 6 100 94 1 T Energy Saved kWh savings Hours of operation x kW saved 8 000 hours x 1 21 9 680 RWh year 109 Figure 25 Energy lost at each step in base case Eight units of Energy Conserved here 90 E Base Case System with improved Piping For every one unit of energy owned at the pipe 24 units of energy saved at the customer s meter just upstream of the motor and eight units of fuel are saved at the power plant nergy input 2 4 Lf f Dee saved here 1 units of Energy Lh saved here aa Plant T amp D Motor Drivetrain Pump Throttle Pipe if Output Energy lost at each step in base case The graph Figure 25 shows the percent of energy lost at each step in the base case system which requires 100 units of fuel input at the power plant to deliver 9 5 units of
163. have higher SHGC e The ECBC addresses energy losses through fenestration by specifying the following fenestration requirements minimum U Factor or Thermal Transmittance maximum Solar Heat Gain Coefficient SHGC and maximum window to wall ratio WWR of 60 for the Prescriptive Compliance Approach EXAMPLE 4 Estimate the U factor for a manufactured fixed fenestration product with a reinforced vinyl frame and double glazine with a sputter type low e coating e 0 10 The gap is 13 mm wide and argon filled and the spacer is metal SOLUTION 4 Locate the glazing system type in the first column of Table 4 Chapter 25 ASHRAE Fundamentals ID 23 then find the appropriate product type fixed and frame type reinforced vinyl The U factor listed in the tenth column of U factors is 1 89 W m2 K EXAMPLE 5 A daytime use building is located in Chennai Warm Humid Zone Given the following information estimate if the building is ECBC compliant through the prescriptive method Also determine the total energy flow through the fenestration system on the south facade of the building South Wall Area 12 160 sqft Window to Wall ratio 1598 12160 13 Fenestration Area 1 598 sqft Fenestration SHCG 0 22 and U factor 3 30 Daily average solar irradiance on south wall 111 3 W m Outside temperature is 30 C and the building is maintained at a temperature of 24 C SOLUTION 5 According to ECBC Table 4 3 buildings lo
164. he design flow rate or 2 the minimum flow required by the equipment manufacturer for proper operation of the chillers or boilers Automatic isolation valves Two way Automatic Isolation Valves serve as a means of varying flow rate in a hydronic system The valve is interlocked to shut off water flow when the compressor is off Since this effectively creates a variable flow system variable speed drive controls are required 19 The ECBC requires two way automatic isolation valves for water cooled air conditioning or heat pump units with a circulation pump motor greater than or equal to 3 7 kW 5 hp The valves must be on each water cooled air conditioning or heat pump unit that is interlocked with the compressor so that the condenser water flow can be shut off when the compressor is not operating Example 7 Hot water system compliance Q A hot water system has two way valves at most coils but occasional three way valves are provided at the end of the branches to ensure flow through them Does this design comply with the ECBC requirement A Yes as long as the total flow through the three way valves does not exceed 50 of design flow Water piping is generally designed for water velocities that are high enough so that the time it takes for chilled or hot water to leave the plant and reach the control valve will be seconds or minutes a small enough time that the system will not be starved and no discomfort will result To minimize en
165. hedules and temperature controls for different zones It is recommended that HVAC zones should be designed according to the orientation of the spaces heating cooling loads variations activity levels occupancy schedules and unique temperature requirements for different parts of the building For example lower temperature set points for overheated computer or equipment rooms etc In cases where a complete HVAC system has been designed for the proposed building the simulation model should be consistent with the design documents It should reflect the actual zoning scheme system type and all actual component capacities and efficiencies Any HVAC specific energy efficiency features example economizers variable air volume drives etc should also be included in the simulation model as per the specifications of the design documents CXXVI The schedules of the building can be prepared by the energy analyst to approximately represent the actual use of the proposed design building The schedules being used should be the same for both the standard design and the proposed design simulation models There are two major differences in modeling the standard design model and the proposed case model The standard design differs from the proposed design model in terms of building envelope U values glazing SHGC lighting power densities and mechanical efficiencies of HVAC systems The other major difference in the building modeling will be the modelin
166. hermore SC is relative to in 3 mm clear glass whereas SHGC is relative to a perfectly transmitting glazing material When SC is available SHGC is established as 0 86 times the SC But these recommendations do not take into account daylighting and the effect that Visible Light Transmission VLT can have on the performance of the overall structure during the heat cool light cycles VLT is the amount of solar radiation in the visible spectrum that passes through fenestration Products with low SHGC generally have a low VLT however if the VLT is too low the view from inside the building will be impaired If you lower VLT too much the daylighting in the interior will be reduced to a level that may require supplemental electrical lighting for some functions or to make the environment enjoyable to the occupants Thus for buildings with lower window to wall ratios WWR higher VLT fenestration systems are permitted under the code The ECBC mandates that the vertical fenestration product shall have the minimum Visual Light Transmittance VLT as an inverse function of Window Wall Ratio WWR under ECBC Section 4 3 3 1 4 2 1 3 Air Leakage Air leakage for glazed swinging entrance doors and revolving doors shall not exceed 5 0 1 s m Air leakage for other fenestration and doors shall not exceed 2 0 1 s m 22 Figure 6 Heat and Air Movement through Double Glazing Window System Glass Pane Outside T 1 Te T P gt P Leg nds
167. hting systems than to manually turn lights off whenever not needed this is not done as often as it could be In response to that problem the ECBC requires several automatic switches that either mark time or sense the presence of occupants A sample diagram for an automatic lighting control system is shown below in Figure 20 All interior lighting systems in buildings larger than 500 m2 5 000 ft are required to be equipped with automatic control devices Within these buildings occupancy sensors must be installed in the following spaces e All office areas less than 30 m2 300 ft2 enclosed by walls or ceiling height partitions e All meeting and conference rooms e All school classrooms and e All storage spaces For other types of interior spaces an automatic control device is required to function on either e A scheduled basis at specific programmed times For this option an independent program schedule must be provided for all areas of no more than 2 500 m2 25 000 ft and not more than one floor or e Occupancy sensors that turn lighting off within 30 minutes of an occupant leaving the space If controlling light fixtures controlled with occupancy sensors the fixtures must also have a wall mounted manual switch capable of turning off the lights when the space is occupied Any buildings designed for 24 hour use are exempt from automatic control requirements 93 Figure 20 Automatic Lighting Control Transformer Power
168. hting that is specifically designated as required by a health or life safety statute ordinance or regulation Any exterior lighting applications not listed in able 7 3 and not exempt as described above are required to simply comply with the mandatory requirements in Section 7 2 3 Exterior Building Grounds Lighting This requires luminaires operating at greater than 100W to contain lamps with minimum efficacy of 60 lm W unless the luminaire is controlled by a motion sensor Table 30 ECBC Table 7 3 Interior Lighting Building Power Building entrance with canopy 13 W m 1 3 W ft of canopied area Building entrance without canopy 90 W lin m 30 W lin f of door width Building exit 60 W lin m 20 W lin f of door width Building facades 2 W m 0 2 W ft of vertical facade area 104 8 ELECTRICAL POWER 8 1 GENERAL Overview There are no prescriptive requirements for the electrical power system Instead the ECBC has only mandatory requirements for energy efficient design of electrical installations in buildings Generally these fall into the following four categories e Minimizing losses in the power distribution system e Reduction of losses and energy wastage in the utilization of electrical power e Reduction of losses due to the associated power quality problems e Appropriate metering General Design Considerations Significant energy savings are sought by maximizing the performance to the electrical distrib
169. ials e g XPS and closed cells polyurethane foams are vapor retarders Please read the discussion about where to place or not to place a vapor retarder Unvented low slope roofs Unfinished ceilings walls and floors for wall applications must consider that most foil faced systems act as a vapor retarder Easy installation suited for standard stud and joist spacing which is relatively free from obstructions Commonly used insulation for retrofits adding insulation to existing finished areas Good for irregularly shaped areas and around obstructions High insulating value for relatively little thickness Can block thermal short circuits when installed continuously over frames or joists Easy installation All suitable for framing at standard spacing Bubble form suitable if framing is irregular or if obstructions are present 37 Insulation Ensure that insulation is installed properly This is important to the overall energy performance of the building and can also affect the durability of the wall structure Plans and drawings should specify that insulation not be compressed behind wiring or plumbing Compressed insulation will have a reduced R value lowering the efficiency of the insulation Specify that insulation fills the entire cavity Batts that are cut too short will leave voids in the wall reducing effectiveness of the insulation For continuous insulation make sure there are no voids and th
170. ibution systems can substantially reduce fan power required by an HVAC system resulting in dramatic energy savings The largest gains in efficiency for air distribution systems are realized in the system design phase for new constructions or major retrofit projects Passive or natural air transport systems have the highest efficiency and successful modern examples of this approach are steadily accumulating For buildings that require mechanical ventilation innovative design approaches and a methodical examination of the entire air system can greatly improve efficiency and effectiveness Air handling efficiency The energy required to move air is calculated as follows Flow Pressure Duty Factor E SERU Efficiency All four of these factors can be manipulated to reduce the energy consumption of the system Air flow has a dominant effect on energy consumption because it shows up twice in the energy equation as the first term and as a squared function in the second term pressure The pressure a fan must work against depends on two primary factors the flow and duct design features such as diameter length surface treatment and impediments such as elbows filters and coils Typical pressure losses are on the order of 2 to 6 inches water gauge wg an efficient system operates at less than 1 5 wg A fan s duty factor is the number of hours per year that it operates sometimes presented as a percentage Many large fans spin at full speed
171. icant energy Decrease in slip Percentage points Increase in efficiency Percentage points efficiency improvement Figure Fans and pumps a special look Since fans and pumps are the most common motor loads their operation deserves closer examination The output of fans and pumps is a struggle between the demands of flow and pressure In general the more pressure they provide the less flow and vice versa This relationship can be plotted on a performance curve as shown in Figure The result is typically a family of curves based on different diameter impellers for pumps or different blade angles for fans Fans and pumps perform optimally in a particular range of flow and pressure head the bull s eye and operate less efficiently outside that region Typical pump performance curves These are whe ackual qutip perlortrince curves showing the rcedonship betwoca pressure total head in fect amd fuss galons per minw Tor a piven impeller diameter the pump periormame will lie on this curve Tise curves show tic brake horsepower BHP required by the pump shaft fora giren poiat on a pump perfrmance curve imernolalion may be required Total head feet Tiest curves show the pump cfficiency at a given puint on the Pochuemance curve Nate ihe half eye of peak efficiency l l l 600 1600 240 3 200 4000 4800 Gallons per minute 8 2 5 Power Distribution Systems 8 2 5 1 Power Distribution System Losses The Cod
172. ighting lighting provided through a building s electrical service for parking lot site roadway pedestrian pathway loading dock and security applications Building material any element of the building envelope through which heat flows and that heat is included in the component U factor calculations other than air films and insulation Circuit breaker a device designed to open and close a circuit by nonautomatic means and to open the circuit automatically at a predetermined over current without damage to itself when properly applied within its rating Class of construction for the building envelope a subcategory of roof wall floor slab on grade floor opaque door vertical fenestration or skylight Coefficient Of Performance COP cooling the ratio of the rate of heat removal to the rate of energy input in consistent units for a complete refrigerating system or some specific portion of that system under designated operating conditions Coefficient Of Performance COP heating the ratio of the rate of heat delivered to the rate of energy input in consistent units for a complete heat pump system including the compressor and if applicable auxiliary heat under designated operating conditions Commercial building all buildings except for multi family buildings of three stories or fewer above grade and single family buildings Construction documents drawings and specifications used to construct a building building systems o
173. ighting design involves sensitive integration of many strategies that include building orientation interior building layout daylight strategies glazing specification choice of lighting system and controls and etc Many things can go wrong with the building lighting system and the well intentioned attempts to make it energy efficient Critical missteps to watch out for include e Specifying the amount of light for general usage without considering the needs of specific tasks for example supplying light for general office work but not addressing the effect of glare on computer screens e Designing a daylighting strategy but not enabling the lighting system to dim or turn off when there is sufficient daylight in the interior space e Supplying inadequate control of lighting by not allowing lights to be adjusted to specific needs i e turned on in groups or banks or dimmed and not providing easily accessible control switches e Adding a large window area to the facade for daylighting but ignoring the problems of solar heat gain and the need for shading e Designing sizing the building s HVAC system on rules of thumb and not accounting for the reduction in cooling The ECBC limits energy consumption and electrical demand by requiring lighting controls specifying exit signs and outdoor ground lighting limiting the amount of power that can be used for lighting in buildings and encouraging daylighting see Envelope section The ligh
174. ighting systems including controls installed in an existing building and any change of building area type as listed in Error Reference source not found shall be considered an alteration Any new equipment or control devices installed in conjunction with the alteration shall comply with the specific requirements applicable to that equipment or control device Exception to 3 1 4 4 Alterations that replace less than 50 of the luminaires in a space need not comply with these requirements provided such alterations do not increase the connected lighting load 3 1 4 5 Electric Power and Motors Alterations to building electric power systems and motor shall comply with the requirements of Error Reference source not found applicable to the portions of the building and its systems being altered Any new equipment or control devices installed in conjunction with the alteration shall comply with the specific requirements applicable to that equipment or control device Example 1 Q An existing warehouse measures 400 ft X 200 ft 125 m X 70m The warehouse is unconditioned but administrative offices are located in a 100 ft X 100 ft 30m X 30m corner The offices are served by a single zone rooftop packaged HVAC system that provides both heating and cooling The owner wants to expand the administrative offices into the warehouse The new office space will convert an area that measures 100 ft X 50 ft 30m X 15m from unconditioned to conditioned space
175. ime switch an automatic time switch that makes an adjustment for the length of the day as it varies over the year Authority having jurisdiction the agency or agent responsible for enforcing this Code Automatic self acting operating by its own mechanism when actuated by some non manual influence such as a change in current strength pressure temperature or mechanical configuration Automatic control device a device capable of automatically turning loads off and on without manual intervention Balancing air system adjusting airflow rates through air distribution system devices such as fans and diffusers by manually adjusting the position of dampers splitters vanes extractors etc or by using automatic control devices such as constant air volume or variable air volume boxes Balancing hydronic system adjusting water flow rates through hydronic distribution system devices such as pumps and coils by manually adjusting the position valves or by using automatic control devices such as automatic flow control valves Ballast a device used in conjunction with an electric discharge lamp to cause the lamp to start and operate under proper circuit conations of voltage current waveform electrode heat etc Boiler a self contained low pressure appliance for supplying steam or hot water Boiler packaged a boiler that is shipped complete with heating equipment mechanical draft equipment and automatic controls usually shipped in one
176. imum U factor or a minimum R value for 24 hour use buildings amp 8 hrs day time use buildings With the prescriptive option each envelope component must separately satisfy the requirements of the Code This is the simplest of all the compliance options If insulation is installed that has the prescribed R value then there is no need to demonstrate compliance with the thermal performance U factor of the construction assembly When using the maximum U factor criteria ECBC Section 11 Appendix C contains defaulted U factors for most constructions so that the user rarely has to calculate a U factor to show compliance Prescriptive design criteria are also provided for fenestration windows glass doors and skylights The fenestration criteria depend on the window to wall ratio in the case of windows and the skylight roof ratio in the case of skylights Window wall ratio WWR is limited to 60 of the gross exterior wall and the skylight roof ratio is limited to 5 of the roof area Fenestration criteria are expressed in terms of maximum solar heat gain coefficient SHGC and maximum U factor Visible light transmission VLT is also prescribed for different values of WWR Requirements for Alterations to Building Envelope Follow the prescriptive requirements for fenestration insulation and air leakage as applicable to the portion of the envelope being altered Do not show compliance with envelope requirements for the following types of enve
177. incorporate the use of cooling towers which improve heat rejection more efficiently at the condenser than air cooled chillers For a water cooled chiller the cooling tower rejects heat to the environment through direct heat exchange between the condenser water and cooling air For an air cooled chiller condenser fans move air through a condenser coil As heat loads increase water cooled chillers are more energy efficient than air cooled chillers A typical chiller is rated between 15 to 1000 tons 53 to 3 500 kW in cooling power 71 What are the different types of chillers Chillers are classified according to compressor type Electric chillers for commercial comfort cooling have centrifugal screw scroll or reciprocating compressors Centrifugal and screw chillers have one or two compressors Scroll and reciprocating chillers are built with multiple smaller compressors e Centrifugal chillers are the quiet efficient and reliable workhorses of comfort cooling Although centrifugal chillers are available as small as 70 tons most are 300 tons or larger Screw chillers are up to 40 smaller and lighter than centrifugal chillers so are becoming popular as replacement chillers Scroll compressors are rotary positive displacement machines also fairly new to the comfort cooling market These small compressors are efficient quiet and reliable Scroll compressors are made in sizes of 1 5 to 15 tons Why must my chilled water sy
178. indows Warm edge insulating glass units for energy efficient windows Frame designs for energy efficient windows Reducing the air leakage of windows to improve energy efficiency Number of layers of glass in the fenestration product The technology for producing energy efficient windows relies heavily on the development of low e coatings for glass These can also be regarded as spectrally selective coatings because their properties vary depending on the wavelength of the incident radiation A low e coating allows the visible light to pass through relatively unaffected whole rejecting invisible infrared heat For example an emissivity of 0 10 means that 90 of the long heat radiation is reflected back The thermal properties of sample glazing products are shown in Table 11 and Table 12 aoe Heat TE Relative Heat Colour Shade Bond Code Cosfiicient Gain SHGC W sqM K W Sqm 41 Single Glazed Unit 6mm thick coating face 2 Light Goia Retlecasol ose 87 so Antelio Plus ST 150 57 ABA Sparkling ce Antero Pus ST 167 58 508 Double Glazed Unit outer 6mm with coating Face 2 12mm Air Gap inner 6mm Clear Double Glazed Unit outer 6mm with coating Face 2 12mm Air Gap inner 6mm Planitherm Total Low E coating Face 3 UghtGola Retecias Jos Table 12 Table 11 Sample Glazing Products and Thermal Qualities Solar Heat Colour Shade Brand Code Gain U value Coefficient Relative Heat Gain
179. ing Central systems designed for VAV system is based on block load calculations as the VAV units allow the system to borrow air from areas with low load By incorporating VAVs with variable speed drive on air handling units it is possible to achieve excellent savings in power Large central systems have life expectancy of 20 to 25 years Central systems allow major equipment components to be kept isolated in a mechanical room Grouping and isolating key operating components allows maintenance to occur with limited disruption to building functions Central systems do not provide flexibility of individual energy metering very easily Central systems are amenable to centralized energy management control schemes and the building management systems BMS The initial purchasing and installation cost of a central air conditioning system is much higher than a local system These systems can offer higher system efficiencies full load and part load and thus can pay pack the elevated initial costs through reduced costs of operations within a few years Extra cost benefits can be achieved due to the potential for energy efficiency measures like thermal heat recovery economizers energy storage systems and etc adjacent one needs cooling two local systems can respond without conflict The compact systems being small are designed for full peak load and the standard rooftop or package units are not typically available with varia
180. ing densityfor appropriate building area categories listed in ECBC s Table 7 1 Interior Lighting Power Building Area Method If more than one listed type applies to the area the more general building area type should be used The second step is to calculate the gross lighted floor area for each of the building area types this can be done using the building plans Finally the last step is to multiply the allowed watts per square meter listed for each selected building type by the corresponding lighted floor areas to determine the allowed watts see Table 27 Table 27 ECBC Table 7 1 Interior Lighting Power Building Area Method 100 Building Area Type LPD W m Multifamily Residential Performing Arts Theater 17 2 Police Fire Station 10 8 Post Office Town Hall 11 8 Religious Building 14 0 School University 12 9 In cases where both a general building area type and a specific building area type are listed the specific building area type shall apply te No o Example 8 Allowed Lighting Power Calculation Building Area Building type New general office space occupying an entire building totaling 10 000 m Allowable lighting power 1 7 watts per m The total allowed watts for the building is determined by multiplying Column B by Column D 17 000 watts poe p e E Tenant Area Building or Allowed Space Watts Building or Area Type Entire Building or Portion of Building Fats parm wats par 0 Borexd
181. ing system at considerable expense In addition to causing energy loss excessive air leakage can cause condensation to form within and on walls This can create many problems including reducing insulation R value permanently damaging insulation and seriously degrading materials It can rot wood corrode metals stain brick or concrete surfaces and in extreme cases cause concrete to spall bricks to separate mortar to crumble and sections of a wall to fall jeopardizing the safety of occupants It can corrode structural steel re bar and metal hangars and bolts with very serious safety and maintenance issues Moisture accumulation in building materials can lead to the formation of mold that may require extensive remediation Virtually anywhere in the building envelope where there is a joint junction or opening there is potential for air leakage Air leakage will cause the HVAC system to run more often and longer at one time and still leave the building uncomfortable for its occupants All openings in the building envelope including joints and other openings that are potential sources of ait leakage are required to be sealed to minimize air leakage ECBC 4 2 3 It means that all gaps between wall panels around doors and other construction joints must be well sealed Ceiling joints lighting fixtures plumbing openings doors and windows should all be considered as potential sources of unnecessary energy loss due to air infiltration Speci
182. ings this is also true of the standards in Russia Ukraine and Kazakhstan for example In Japan there are standards for both residential and commercial buildings but the buildings must have at least 2 000 square meters of floor space to be covered Most countries that regulate both commercial and residential construction for energy efficiency have separate standards for each although countries categorize the buildings differently In India Australia Canada and the U S the codes consider commercial buildings to include multi family residential buildings while in China and Japan the residential standards regulate such multi family residences This difference is important because typically the commercial building requirements are somewhat more complex and cover more issues than those for residential buildings Specific Requirements The actual efficiency requirements for new buildings vary between countries While it would not be possible to highlight the full range of variation in a summary of this size a few examples may help to illustrate this point The table below highlights differences between the requirements for several building components in India Australia China and the U S Snapshot of Building Energy Efficiency Maximum U Factors and Lighting Power Densities in the U S China and India Units W m K for U factors i p 0 409 for most Roof 0 358 0 9 buildings 0 261 for 0 313 24 hr buildings 0 642 to 3 293 0 556
183. ion can be controlled by careful caulking and weather stripping Internal loads are heat gains from lights Infiltration Radiation equipment and people in the building Figure 5 They consist of both sensible gains elevated air temperatures and latent gains moisture added to the space Lighting and most electrical equipment produce only sensible gains while people and outdoor air ventilation produce both sensible and latent loads Although internal loads primarily result from the way a building is used rather than from the envelope design the introduction of daylight can reduce dependence on electric light and thus reduce internal heat gain from electric lighting The ideal building envelope would control Figure 5 Internal Load exterior loads in response to coincident internal loads to achieve a thermal balance for each set of conditions When the conditioned building is in a cooling mode solar gains should be reduced while still admitting daylight Outdoor air should be introduced during evening hours to cool thermal mass in preparation for the next day s loads If the building is in a heating mode during the day solar gains should be increased while heat losses due to both conduction and infiltration should be reduced Therefore in practice the architects and building designers need to integrate and balance these varying considerations while designing an energy efficient building Machines and In most buildings
184. ived from standards produced by the American Society of Heating Refrigerating and Air Conditioning Engineers ASHRAB although specific requirements in each country vary European Union countries are all required to adopt legislation harmonized with the Directive on Energy Performance in Buildings which provides guidelines for the performance of buildings including the envelope HVAC lighting in non residential building orientation and passive solar systems This report is primarily based on a series of country reports describing building energy codes in the Asia Pacific region that the Pacific Northwest National Laboratory prepared with U S Department of Energy support under the Asia Pacific Partnership on Clean Development and Climate a Some countries refer to their building energy regulations as codes and others call them standards i Please see www energycodes gov for details Jens Lausten 2008 Energy Efficiency Requirements in Building Codes Energy Efficiency Policies for New Buildings International Energy Agency Paris Comparison of Elements Covered in Selected Commercial Building Standards and Codes Australia Canada China India Japan Korea U S ASHRAE 90 1 2007 SSS separate standard Not all standards and codes cover the same types of buildings either For example in India the Energy Conservation Building Code ECBC covers commercial and multi family residential buildings but not small residential build
185. just HVAC operations based on environmental conditions changing uses and timing Create an energy management system to automatically monitor and control HVAC lighting and other equipment Upgrade fuel burning equipment e Install a more efficient burner e Install an automatic flue damper to close the flue when not firing e Install turbulators to improve heat transfer efficiency in older fire tube boilers e Install an automatic combustion control system to monitor the combustion of exit gases and adjust the intake air for large boilers e Insulate hot boiler surfaces e Install electric ignitions instead of pilot lights Evaluate thermostat controls and location e Install programmable thermostats e Lock thermostat to prevent tampering e Ensure proper location of thermostat to provide balanced space conditioning e Note the proximity of the heated or cooled air producing equipment to thermostat Evaluate boiler operations e Investigate preheating boiler feed water e Adjust boilers and air conditioner controls so that boilers do not fire and compressors do not start at the same time but satisfy demand e Use hot water from boiler condensate to preheat air Use existing cooling towers to provide chilled water instead of using mechanical refrigeration for part of the year Install water meters on cooling towers to record makeup water usage Install controls on heat pump if has electric resistance heating elements to minimize use
186. k building designs and inspect the buildings for compliance There is no single answer as to which system produces the highest level of compliance For example Japanese officials believe that Japan attains a high level of compliance in actual construction because Japan has a very well developed system of training and information dissemination on the building energy standards Studies in the U S have shown that there physical inspections result in much higher compliance rates The stringency of the national system for testing materials and equipment for their energy efficiency properties can also have a marked impact on the final energy consumption of a building Most countries have a system of certified laboratories that test materials and equipment like windows and air conditioners and rate them for efficiency These ratings then determine if the equipment in a building meets the building energy standard Testing procedures vary between countries and there is anecdotal evidence that even in countries with well established systems ratings can differ by 10 or more based on the testing procedures Building energy standard compliance rates vary significantly between countries What constitutes compliance may also vary and not all countries consistently publish compliance data That said countries usually have lower compliance rates soon after they adopt or revise a standard and when their enforcement system is not fully developed Options for I
187. l city location Weather files for 58 cities from India are available at http www cere energy gov buildings energyplus cfm weather_data3 cfm region 2_asia_wmo_tregion_2 country IND cname India The specifications of standard design simulation model are generated in accordance with the modeling requirements set forth by the ECBC Table 10 1 of Appendix B The standard model is created with building specifications building envelope HVAC system lighting service water heating internal loads etc that comply with all prescriptive requirements of the ECBC For example the building envelope specifications like the orientation and the heat capacity of materials follow the requirements set forth by Table 10 1 4 of Appendix B Currently the ECBC does not mandate any compliance requirements for the thermal performance of underground walls floors and slab on grade floors in buildings For these building envelope elements and other building components currently not regulated by the ECBC the inputs for the standard design simulation model should be similar to the specifications for the proposed designed The ASHRAE 90 1 2004 standard may also be used as a reference source to estimate U values and overall thermal performance guidelines for building envelope components not regulated by the ECBC 9 2 3 1 Space For the purposes of this case study the entire floor plate is assumed to be one conditioned area since the HVAC zoning of the building is not
188. lacement of Barriers Exterior Cladding Air und Water Racrlor Yapar opes Thormal Inraktlon Uj Exterior Cladd ng Te Ak and Warer Burrivr Vupor open f MN IOWIIUT its IOWIIUT Air uml Water Rareler Vapor apen Seructural Wall Interior Cladding is ho D m m a m t a a a a a S n aa t m Sn i Sn t a O m M h O S N an t A OOo ity Vapor Rarrlerf Retarder Srructural Wall Interline Chdding coal es oo Yj w N Hee eee a a a eee ee A a a a a a a mA A A e a a e a a Te aa a a a a a e a a a s a a T a a A TA y i PA A f 4 4 4 Y yl 4 A 4 N In hot composite and humid climate zones Vapor permeable materials which allow drying in both directions are preferable In cold and temperate climates or where the internal humidity and temperature is likely to be relatively higher than the outside it must be ensured that materials that make up the envelope are progressively more Vapor permeable from the inside to the outside or are vented towards the outside so that if the envelope components such as insulation get wet they can dry themselves through Vapor diffusion Metal roofs with under deck fibrous insulation present unique challenges in moisture management Since the metal sheet prevents active drying of insulation to the outside it is recommended that on the inner side the insulation be faced with a Vapor open air and water barrier to allow incid
189. lements by which energy is transformed so it performs a specific function such as HVAC service water heating or lighting System existing a system or systems previously installed in an existing building Terminal a device by which energy form a system is finally delivered e g registers diffusers lighting fixtures faucets etc Thermal block a collection of one or more HVAC zones grouped together for simulation purposes Spaces need not be contiguous to be combined within a single thermal block Thermal Zone It is a term used in energy simulation to represent area catered to by one air conditioning unit With the help of the zoning building plans are simplified to reduce the modeler s work Normally within one zone usage pattern set point temperature and other conditions are identical Building spaces that would experience similar heating and cooling loads are generally grouped under one zone Thermostat an automatic control device used to maintain temperature at a fixed or adjustable set point Tinted as applied to fenestration bronze green or grey coloring that is integral with the glazing material Tinting does not include surface applied films such as reflective coatings applied either in the field or during the manufacturing process CXL Ton One ton of cooling is the amount of heat absorbed by one ton of ice melting in one day which 1s equivalent to 12 000 Btu h or 3 516 thermal kW Transformer a piec
190. ling load and enable the economizer by adjusting the lockout control set point Verify and document the following e Economizer damper modulates opens to 100 outside air e Return air damper modulates closed and is completely closed when economizer damper is 100 open e Economizer damper is 100 open before mechanical cooling is enabled e Relief fan or return fan if applicable is opening or barometric relief dampers freely swing open Step 2 Continue from Step 1 and disable the economizer by adjusting the lockout control set point Verify and document the following e Economizer damper closes to minimum ventilation position e Return air damper opens to at or near 100 e Relief fan if applicable shuts off or barometric relief dampers closed Return fan if applicable may still operate even when economizer is disabled 5 3 2 Variable Flow Hydronic Systems Fluid from the heating or cooling source is supplied to heat transfer devices such as coils and heat exchangers and back through the hydronic system The ECBC requirements specify the type of equipment and capabilities in such a way to reduce pump energy Variable fluid flow automatic isolation valves and variable speed drives enable the system to operate below design flow when possible Variable fluid flow The ECBC requires that chilled or hot water systems be designed for variable fluid flow and are capable of reducing pump flow rates to no more than the larger of 1 half of t
191. lled general and task lighting shown on the plans Interior lighting for a building or a separately metered or permitted portion of a building shall not exceed allowed power limits For Interior Lighting Power requirements the installed interior lighting power is first calculated to include all lamps ballasts current regulators and controls A Lighting Summary Sheet is included in ECBC See Figure 204 Compliance can then be achieved by following the Building Area Method or the Space Function Method Both methods compare installed lighting power as proposed with maximum allowed lighting power densities W m presented in tables based on either building area type or space function When following either the Building Area or Space Function method the installed interior lighting power must be determined through calculation described in ECBC Section 7 3 4 The building area method is the simplest method to follow since fewer calculations are required However if the project applies to only a portion of the entire building is not listed as a building type or has more than one occupancy type the space function method should be used to determine compliance Trading of lighting power allowances are not permitted between portions of a building where different methods were used There are many exceptions to the lighting power requirement generally for specialized lighting These are listed in ECBC Section 7 3 1 Lighting Power Exemptions e
192. lope alterations which do not increase building energy use e Replacement of glass in an existing sash and frame the U factor and SHGC of the replacement glazing must be equal to or lower than the existing glazing e Modifications to roof ceiling wall or floor cavities these must be insulated to full depth with insulation and e Modifications to walls and floors that do not have cavities and where no new cavities are created Envelope Trade Off Approach This is a systems based approach where the thermal performance of individual envelope components can be reduced if compensated by higher efficiency in other building systems or components 1e using higher wall insulation could allow for a less stringent U value requirement for windows or vice versa These trade offs typically occur within major building systems envelope lighting or mechanical This method offers the designer more flexibility than strictly following the prescribed values for individual elements The thermal performance of one envelope component such as the roof can fail to meet the prescriptive requirements as long as other components perform better than what is required Trade offs are permitted only between building envelope components It is not possible for instance to make trade offs against improvements in the lighting or HVAC systems However this makes using the envelope trade off option more complicated than the prescriptive method It is necessary to
193. lso be eligible for exterior use Luminaires with modular components that allow conversion between screw based and pin based sockets without changing the luminaire housing or wiring are not considered high efficacy luminaires These requirements prevent low efficacy lamps from being used in high efficacy luminaires Also in compact fluorescent luminaires with permanently installed ballasts that are capable of operating a range of lamp wattages the highest operating input wattage of the rated lamp ballast combination must be use for determining the luminaire wattage There are two qualifying requirements for a high efficacy luminaire 1 the lumens per watt for the lamp must be above a specified threshold and 2 electronic ballasts must be used in certain applications What are the requirements for recessed fixtures Luminaires that are recessed into insulated ceilings should be rated for insulation contact IC rated so that insulation can be placed over them The housing of the luminaire should be airtight to prevent conditioned air from escaping into the ceiling cavity or attic and unconditioned air infiltrating from the ceiling into the conditioned space Lighting for security purposes is a big concern how is it regulated Lighting that is specifically designated as required by a health or life safety statue ordinance or regulation is exempt from the exterior lighting power requirement For required internal space controls
194. ly with the building envelope HVAC systems service hot water and pumping lighting systems electric transformers electric motors power factor correction systems and power distribution system An alternative compliance method is described in Appendix B the Whole Building Performance WBP or Energy Cost Budget method Existing Building Compliance The Code also applies to certain work in existing buildings The requirements are triggered when new construction is proposed such as an addition or when unconditioned space is converted to conditioned space that is heating and or cooling are added for the first time The Code applies to additions and alterations much as it does to new buildings the Mandatory Provisions must always be met after that either the prescriptive or whole building performance approach for compliance may be applied However in existing buildings there is a general exception to the Code whenever compliance with the requirements can be shown to cause an increase in the building s annual energy use Compliance details are discussed below for additions alterations and changes in conditioned space 3 1 3 Additions to Existing Buildings An addition is a new wing or new floor that extends or increases the building floor area or height of a building outside the envelope of the existing building When building an addition the additional construction must comply with the ECBC only if the original plus additional condition
195. ly mutual radiation exchanges between the inner surfaces of the building also occur for example between walls or between a wall and roof Such heat transfer processes affect the indoor temperature of a room and consequently the thermal comfort experienced by its occupants Solar Absorbed Corector Radiation by wall Absorbed Longwave by wall eon I radiation Reflected Convection Radiation INSIDE OUTSIDE Source Nayak amp Prajapati 2006 Handbook On Energy Conscious Buildings 17 ECBC Compliance The ECBC building envelope requirements are based on the climate zone in which the building is located ECBC defines five climate zones hot dry warm humid composite temperate cold which are distinctly unique in their weather profiles Appendix E Based on the characteristics of climate the thermal comfort requirements in buildings and their physical manifestation in architectural form are also different for each climate zone See below Table 3 These physical manifestations in turn dictates the ECBC requirements for the envelope as well as other building components that are applicable to the building Table 3 Comfort Requirements and Physical Manifestations in Buildings Thermal Requirements Physical Manifestation Resist Heat Gain Decrease air exchange rate ventilation during day time Weather stripping and scheduling air changes External surfaces protected by overhangs fins and Increase aaa tre
196. measured horizontally from the exterior unconditioned er Space Space sutface it is measured vertically from the top of the floor to the bottom of the roof Zone HVAC A space or group of spaces within a building with heating and cooling requirements that are sufficiently similar so that desired conditions e g temperature can be maintained throughout using a single sensor e g thermostat or temperature sensor CXLII 10 3 ABBREVIATIONS AND ACRONYMS AFUE ANSI ARI ASHRAE ASTM BIS Btu Btu h Btu ft2 F Btu h ft2 Btu h ft F Btu h ft F C cfm cm COP DOE EER EC Act 2001 EF F ft h HC h ft2 F Btu h m2 C W hp HSPF HVAC I P in Annual fuel utilization efficiency American National Standards Institute Air Conditioning and Refrigeration Institute American Society of Heating Refrigerating and Air Conditioning Engineers American Society for Testing and Materials Bureau of Indian Standards British thermal unit British thermal units per hour British thermal units per square foot per degree Fahrenheit British thermal units per hour per square foot British thermal units per lineal foot per degree Fahrenheit British thermal units per hour per square foot per degree Fahrenheit Celsius Cubic feet per minute Centimeter Coefficient of Performance Department of Energy U S Energy Efficiency Ratio Energy Conservation Act 2001 Energy Factor Fahrenheit Foot Hour Heat
197. mes heated Although some surfaces such as galvanized metal have a high reflectance they have a low emittance These surfaces reflect heat but heat that is absorbed cannot escape Other surfaces such as dark paint have a high emittance but a low reflectance These surfaces allow heat to escape but do a poor job of reflecting heat that strikes the surface Most cool roof materials for low sloped roofs are white or another light color For steep sloped roofs that are often visible from the ground roofing material manufacturers have developed popular roof colors other than white that will still reflect or emit the sun s energy away from the building In accordance with ECBC Section 4 3 1 1 roofs with slopes less than 20 degrees shall have an initial solar reflectance of no less than 0 70 and an initial emittance no less than 0 75 Solar reflectance shall be determined in accordance with ASTM E903 96 and emittance shall be determined in accordance with ASTM E408 71 RA 1996 Cool roofs have other benefits in addition to reducing operating costs For building owners they can cut maintenance costs and increase the life expectancy of the roof For society in general cool roofs can even help to reduce the urban heat island effect that makes our cities hotter and produces unhealthy air FAQs 1 Cool Roofs What is a Cool Roof Cool roofs are highly reflective and emissive materials that stay 10 to 16 degrees C cooler in the sun thereby red
198. nal Performance Factor HSPF is the measurement of how efficiently all residential and some commercial heat pumps will operate in their heating mode over an entire normal heating season The higher the HSPF the more efficient is the system HSPF is determined by dividing the total number of Btu of heat produced over the heating season by the total number of watt hours of electricity that is required to produce that heat The Annual Fuel Utilization Efficiency AFUE is the measurement of how efficiently a gas furnace or boiler will operate over an entire heating season The AFUE is expressed as a percentage of the amount of energy consumed by the system that is actually converted to useful heat For instance a 90 AFUE means that for every Btu worth of gas used over the heating season the system will provide 0 9 Btu of heat The higher the AFUE the more efficient is the system FAQs 6 Air Handling Unit Concepts What is an Air Handler An air handler is responsible for moving air throughout the duct work in an air conditioning system All air handlers contain a blower motor and squirrel cage blower housing which facilitates the movement of air Most air handlers also include system controls which are connected to the thermostat Depending on the type of system an air handler can also be integrated with a gas oil electric furnace heat pump and cooling coils or evaporator coil for the air conditioning High efficiency air distr
199. ncy level with above 80 efficiency e Reference IS 2082 electric water heaters much meet the described performance minimum efficiency levels 83 Energy Factor EF and thermal efficiency Et ratings which measure the overall efficiency of water heater systems are set as minimum requirements The mandatory standby loss SL 1s set as a maximum Btu h Fifteen to thirty percent of the energy consumed by a standard water heater goes to keeping the water hot while it s not being used This lost energy is called standby loss Gas water heaters have higher standby losses than electric water heaters because of the uninsulated flue running up the center of the tank Demand heaters also called tankless or instantaneous heaters reduce standby loss by heating water only as it flows through the heater on its way to a faucet actually in use Instantaneous water heaters with input rates below 58 62 W must comply with these requirements if the water heater is designed to heat water to 82 2 C or higher Advantages of heat pumps Heat pump water heaters are more efficient since electricity is used to transfer heat in a vapor compression cycle A heat pump water heater is an electric water heater that uses a compressor to transfer thermal energy from one temperature level to a higher temperature level Energy Factors for heat pump water heaters are over 1 5 Water Heating System Efficiency Reduce standby losses from storage tank and pipes Lowet Water
200. nd building assemblies used locally As the demand for products grows there will likely be more competition and choice available to designers In the meantime it is important to note that construction technique i e proper air sealing around joints and windows installation of vapor barriers and insulation and correct use of shading devices for windows has a significant impact on energy efficiency along with the energy efficiency of individual components Local jurisdictions will determine the specific documentation required to demonstrate compliance Recommended materials to submit for a permit application include the following Building Envelope e Insulation materials and R values e Fenestration U factors SHGC visible light transmittance if using the trade off approach and air leakage e Overhang and sidefin details e Envelope sealing details e Type of systems and equipment including their sizes efficiencies and controls e Economizer details e Variable speed drives e Piping insulation e Duct sealing e Insulation type and location e Report on HVAC balancing Service Hot Water and Pumping e Solar water heating system details Lighting e Schedules that show type number and wattage of lamps and ballasts e Automatic lighting shutoff details e Occupancy sensors and other control details e Fxterior lamp efficacy Electrical Power e Schedules that show transformer losses motor efficiencies and power
201. nd envelope sealing 4 2 1 Fenestration Glazing products or fenestration windows doors and skylights can be specified to reduce solar heat gain and control light levels and glare Heat transfer and energy losses occur through fenestration by conduction convection and long wave infra red radiation See Figure 6 For heat flow through fenestration apart from the minimum U factor or thermal transmittance the Solar Heat Gain Coefficient SHGC Minimum Visible Transmission VLT or VT and the maximum window to wall ratio WWR are taken into consideration Window to Wall Ratio WWR is the proportion of window area compared to the gross wall area Gross exterior wall area is measured horizontally from the exterior surface it is measured vertically from the top of the floor to the bottom of the roof 4 2 1 1 U Factors U Value 1 R value Clear glass which is the most common type of glass used today has no sionificant thermal resistance R value from the pane itself however it has a value of R 0 9 to R 1 0 due to the thin films of air on the interior and exterior surfaces of the glass The R value and U factor thermal transmittance must account for the entire fenestration construction including the effects of the frame the spacers in double glazed assemblies and the glazing There are a wide variety of materials systems and techniques used to manufacture fenestration products and accurately accounting for these factors is o
202. nd may not necessarily blend well with the aesthetics A local HVAC system typically serves a single thermal zone and has its major components located within the zone itself or directly adjacent to the zone Multiple units are required for multiple zones Local units are off shelf items complete with integrated controls They usually have a single control point which is typically only a thermostat The room by room or zone Control minimizes overcooling typical of central air conditioning systems With the zone control ability of the compact systems only occupied spaces are maintained at a comfort level and conditioning for the rest of the building is turned down or shut off The air quality is not comparable to central systems These systems typically cannot provide close humidity control or high efficiency filtration The compact systems being standard factory items typically cannot be modified to suit the required design conditions all the times In a building where a large number of spaces may be unoccupied at any given time such as a dormitory or a motel local systems may be totally shut off in the unused spaces thus providing huge energy saving potential As a Self contained system a local HVAC system may provide greater occupant comfort through totally individualized control options if one room needs heating while an 56 CENTRAL SYSTEMS LOCAL SYSTEMS Operations and Maintenance O amp M Monitor
203. ndard design and proposed system is similar Alternatively these results may indicate that some part of the HVAC system is undersized and may require redesign These models are refined and re run and checked for all the compliance clauses again and if found in order prepared to compliance documentation checks 9 2 6 Step 6 Documentation of the Compliance Process For the project to finally comply with the code the required compliance documents should be prepared and filed to show that the proposed design consumes less or equal energy than the standard design model Given below are tables showing a comparison of the data inputs used to generate the standard and the proposed design simulation model for this particular case study building in Gandhinagar Gujarat Table 30 Activity E Proposed Building Standard Design All zones 70 sq ft person All zones 70 sq ft person O Schedule 8am 8pm Schedule 8am 8pm ccupancy One central zone lobby areas 500 One central zone lobby areas 500 sq sq ft person ft person DHWeonsumpionrate Jo oo o O o o Seeme Seneu ado Miscelleneous None None Catering None None Table 31 Construction Proposed Building External walls 0 5 stone cladding 0 5 Plaster 9 Clay brick 0 5 Plastering outside to inside U value 1 75 W sq m K Flat roof Overdeck insulation RCC 4 Slab 0 5 plastering outside to inside U value 0 072 Btu sq ft F 0 409 W sq m K 0 5 Plaster 9 Clay brick 0 5 Pl
204. ndia to Consider India has taken a purposeful step toward improved building energy efficiency in adopting the Energy Conservation Building Code The next step is implementing this code which could require concerted efforts both at the state and national levels States would need to decide to adopt the code The national government could also help with this learning process by requiring 2 R E Horne et al 2005 nternational Comparison of Building Energy Performance Standards Centre for Design RMIT University Melbourne Australia VI that all new government buildings meet the building energy code For example the national government might provide tools to help states and local jurisdictions with enforcement India has a well developed system to enforce other types of building codes and it might use this system for enforcing the building energy code as well Building energy inspectors at the local level might need training and local jurisdictions could hire some staff to handle the additional workload India could also try to simplify the implementation task by developing code compliance software that allows building developers and inspectors to easily check the building design for compliance Such software could also be designed to automatically develop inspection checklists As India gains experience with implementing its code it might want to modify the code periodically Many countries have found that establishing a regular timetable for suc
205. nearly the same at all speeds fan power is proportional to flow times pressure It turns out that both of these variables depend on the speed of the fan Flow is proportional to speed double the speed double the flow Pressure however is proportional to speed squared double the speed quadruple the pressure because it is controlled by friction which increases as air moves faster If we combine these relationships we see that fan power is proportional to speed times speed squared or speed cubed It is the fact that fluid friction climbs steeply with speed that limits the maximum speed of a bicyclist on a flat road with no wind air is a fluid This relationship generally applies to all types of fluid friction in ducts and piping systems 112 Drivepower s share of U S electricity use by end use How much Where U S aad 7 is used by electricity store flows TOROS 9 ae F z z 5 5 ue 43 T __ff 8 2 4 Check Metering and Monitoring A significant barrier to achieving energy efficiency during the operation of a building is inadequate metering systems and monitoring plans Building operators cannot be expected to manage energy if they cannot measure energy use To improve a building s energy performance over its operating life and optimize the energy efficient requirements in the code the ECBC requires that the building s performance be measured Metering is about having information that allo
206. ng model should be served by a water cooled chiller with a variable air volume VAV AHU for each zone along a electric resistance heating source In the proposed design there is no heating system being provided for the building however since the standard design building should also be modeled with heating the same kind of provision is assumed for the proposed design simulation model too 9 2 3 6 2 Fans and controls As specified in the mandatory provisions as in Section 5 2 3 all the mechanical cooling and heating systems shall be controlled by respective schedules and set point temperatures The supply fans should be controlled by variable speed drives as specified by the standard in Section 5 3 2 9 2 3 6 3 Chiller sizing The sizes of the chiller which decides the COP of the chiller as per Table 5 1 of Section 5 2 2 of the code is considered from the following table See Table 3434 Table 34 Chiller Sizing for the Case Study Building lt 600 tons 1 centrifugal chiller gt 600 tons amp lt 1200 tons 2 centrifugal chiller equally sized gt 1200 tons Multiple centrifugal chillers equally sized Each chiller not greater than 800 tons To determine the sizes of the chiller a sizing run of the standard design model is performed The sizing ratios for this model would be 15 oversized for the cooling and 25 oversized for the heating unit as mentioned in the code Depending of the tonnage of the each chiller the COP of the chill
207. nt bubble the total light flow through the bubble is measured in lumens Lamps are rated in lumens which is the total amount of light they emit not their brightness and not the light level on a surface Typical indoor lamps have light output ranging from 50 to 10 000 lumens Lumen value is used for purchasing and comparing lamps and their outputs Lumen output of a lamp is not related to the light distribution pattern of a lamp Luminaries a complete lighting unit consisting of a lamp or lamps together with the housing designed to distribute the light position and protect the lamps and connect the lamps to the power supply Manual non automatic requiring personal intervention for control Non automatic does not necessarily imply a manual controller only that personal intervention is necessary Manufacturer the company engaged in the original production and assembly of products or equipment or a company that purchases such products and equipment manufactured in accordance with company specifications Mean temperature one half the sum of the minimum daily temperature and maximum daily temperature Mechanical cooling reducing the temperature of a gas or liquid by using vapor compression absorption and desiccant dehumidification combined with evaporative cooling or another energy driven thermodynamic cycle Indirect of direct evaporative cooling alone is not considered mechanical cooling Metering instruments that measure electric volt
208. nt induction should be minimized and a proper blow down rate should be maintained Water treatment regimens are effective for water conservation keeping the cooling loop cleaner saving energy reducing maintenance and improving reliability of the entire cooling system New technological solutions like hybrid wet dry cooling tower designs which combine wet and dry cooling can be adopted to reduce water use some as much as 70 compared to conventional towers Typically a dry finned coil section is combined in series with an evaporative section in these units The dry finned section handles as much of the load as possible with the unit able to operate completely dry at reduced ambient Both open and closed circuit versions are available Source Morrison F What s up with Cooling Tower 2004 ASHRAE Journal 46 7 Many electric motor driven devices operate at full speed even when the loads they are serving are at partial capacity Motors with multiple speed capability can match the output of the device to the load to save energy Variable frequency drive VFD motors are one of the most effective options VFDs accomplish part load control by varying electric motor speed and commonly save 50 percent or more energy over other part load control strategies FAQ 8 What is a Variable Speed Drive A variable speed drive VSD is an electronic device that controls the rotational speed of a piece of motor driven equipment e g a blower com
209. ntilation requirements buildings must follow the design guidelines provided for natural ventilation in the National Building Code of India 2005 Part 8 5 4 3 and 5 7 1 ECBC 5 2 1 Ventilation can not only provide fresh air that improves the indoor air quality but an effective design incorporating passive solar elements can be effective and reducing the cooling loads on the HVAC system as seen in Figure 15 below 62 Figure 15 Cross Ventilation Schematic Radiation heat removed A in draft through high Radiation heat windows NS i A Saa Xi r of y Cross Ventilation 5 2 2 Minimum Equipment Efficiencies A wide range of efficiencies are available for HVAC system components Minimum equipment efficiencies are required to be met for all installed equipment including Unitary Air Conditioning Equipment Chillers Heat Pumps Heating Mode Furnaces and Boilers All heating and cooling equipment must meet or exceed the minimum efficiency requirements presented in Section 5 of ECBC Many of these requirements are based on those developed for the American Society of Heating Refrigerating and Air conditioning Engineers ASHRAE Standard 90 1 Any equipment not listed in the tables should refer to the efficiencies in ASHRAE Standard 90 1 2004 Section 6 4 1 for guidance The minimum energy performance standards for chillers are presented in Table 21 Selection of individual equipment efficiency should be considered in the contex
210. o run efficiently An integrated design approach brings together the various disciplines involved in designing a building and its systems and reviews their recommendations in a comprehensive manner It recognizes that each discipline s recommendations have an impact on other aspects of the building project This approach allows for optimization of both building performance and cost Often the architect mechanical engineer electrical engineer contractors and other team members pursue their scope of work without adequate interaction with other team members This can result in oversized systems or systems that are not optimized for efficient performance for example indoor lighting systems designed without consideration of day lighting opportunities ot HVAC systems designed independently of lighting systems Design integration is the best way to avoid redundancy or conflicts with aspects of the building planned by others An integrated design approach allows professionals working in various disciplines to take advantage of efficiencies that are not apparent when they are working in isolation It can also point out areas where trade offs can be implemented to enhance resource efficiency The earlier that integration is introduced in the design process the greater the benefit 3 4 COMPLIANCE DOCUMENTS 3 4 1 General The documents submitted should include sufficient detail to allow thorough review by the code enforcement agency for compliance with ap
211. of motor loading may never occut Although motor over sizing can be an expensive problem in the long run there are significant institutional and cultural reasons why motors are frequently and persistently oversized e When process systems are designed their maximum torque requirements are noted for future motor selection Unfortunately this maximum torque value is usually translated into the minimum acceptable continuous torque for the motor even if the maximum process torque is required for only a small fraction of the motor s duty If any of the design parameters of a system are poorly defined or expected to change motors are often oversized in an attempt to compensate for this uncertainty Many systems are designed and constructed with future expansion in mind Despite these good intentions many of these expansions never occur or occur in a dramatically different way than originally imagined So even if the motors and loads were sized appropriately for application in the expanded system they may run under loaded for years prior to its completion In short the methods by which motors are often selected can be characterized as an attempt to avoid the conspicuous failure of a grossly undersized motor by accepting the certain failure of an inefficiently applied and grossly oversized motor Paradoxically the cost of replacing a few inadvertently undersized motors with slightly larger models pales in comparison to the enormous added co
212. of the roof assembly is provided depending on the kind of building and the climate it belongs to Also the required specification of the roof albedo is mentioned in Table 10 1 4 of Appendix B which says the roof should be modeled with a reflectivity value of 0 3 9 2 3 4 Windows Windows in all the directions of the building have the same requirements of SHGC and U value This U value and the SHGC depend mainly on the window wall ratio WWR and the climate zone thatthe building belongs to The WWR is the ratio of window area to the total wall area This WWR is calculated and defined as in Appendix A of the code The related terms for this window wall ratio as mentioned in Appendix A are the Wall area gross and the Window wall ratio WWR The modeling aspects of the fenestration are specified in Table 10 1 4 of Appendix B of the code The U value SHGC and the visible transmittance to the glass are from Table 4 3 of Section 4 3 3 of the code All the windows in the standard design model of this particular case study have a U value of 3 3 W sq m K and SHGC of 0 25 9 2 3 5 Lighting The lighting power density LPD of the standard design model should be defined either using the building area method or the space function method as specified in Table 10 1 5 of Appendix B The building area method as specified in Section 7 3 2 Table 7 1 of the code is where an average LPD value is defined for the entire building where as in the space function method as in
213. omplete floor plate would be considered as conditioned area and the perimeter areas minimum till 4 5 meter from exterior wall in different orientations would be considered as different thermal blocks with a central core area This zoning pattern will be same for both proposed case design model and the standard design model Figure 35 Simplified Zoning of the Case Study Building When HVAC Zoning Not Designed In this case study of the proposed building the HVAC zoning is not yet designed Therefore a perimeter and core zoning following the 8m x 8m grid of the building has been used in the simulation model Error Reference source not found 5 shows the considered zoning pattern of a typical floor HVAC ZONING FOR ENERGY SIMULATION Energy simulation of any building should only be undertaken after the HVAC system and all its specifications have been finalized as this has a major influence on the energy performance of the building The representative perimeter and core HVAC zoning scheme used to simulate this case study building has been adopted only due to the non availability of the zoning scheme for the proposed building The perimeter and core zoning technique simplifies the data input process but does not represent standard energy simulation procedure nor does is this technique representative of energy modelling HVAC zoning best practices Zoning an HVAC system allows the ability to set individualized mechanical performance sc
214. ooms 2 5 W sq ft Conditioned rooms 1 W sq ft 10 8 W sq Lighting power density m Parking 1 W sq ft Parking 0 3 W sq ft 3 2 W sq m Table 34 HVAC TF oew serao MECHANICAL VENTILATION Toasty o ooo o Fana wo o o NA NA NA com o Table 40 Schedule 8 am to 8 pm working Time Occupancy 8am 9am 9am 10m 10am 11am 11am 12noon 4pm 5pm Spm 6pm 6pm pm 7pm 8pm CXXX 10 ECBC DEFINITIONS ABBREVIATIONS AND ACRONYMS 10 1 GENERAL Certain terms abbreviations and acronyms are defined in this section for the purposes of this code These definitions are applicable to all sections of this code Terms that are not defined shall have their ordinarily accepted meanings within context in which they are used Webster s Third New International Dictionary of the English Language Unabridged copyright 1986 shall be considered as providing ordinarily accepted meanings 10 2 DEFINITIONS Addition an extension or increase in floor area or height of a building outside of the existing building envelope Alteration any change rearrangement replacement or addition to a building or its systems and equipment any modification in construction or building equipment Annual fuel utilization efficiency AFUE an efficiency description of the ratio of annual output energy to annual input energy as developed in accordance with requirements of U S Department of Energy DOE 10CFR Part 430 Astronomical t
215. or multiplier In this case the M is 0 79 Multiplying M times the SHGC 0 7900 0 25 0 1975 and thus complies with ECBC Table 4 3 SHGC Requirements Exception to ECBC Section 4 3 3 In addition to the SHGC exception above for overhangs and or side fins the ECBC encourages the use of daylighting by allowing for SHGC exceptions for vertical fenestration located more than 2 2 m 7 ft above the level of the floor provided the following conditions are complied with The Total Effective Aperture for the elevation is less than 0 25 including all fenestration areas ereater than 1 0 m 3ft about the floor level and An interior light shelf is provided at the bottom 2 2 m or higher of this fenestration area with an interior projection factor PF not less than e for E W SE SW NE and NW orientations e 0 5 for S orientations and e 0 35 for N orientation when latitude is lt 23 degrees 46 Daylighting Strategies Effective daylighting strategies should include some combination of the following e Exterior shading Overhangs and vertical fins block direct sun and can bounce reflected light into interior spaces Interior light distribution Light shelves diffusers or reflective surfaces move the light further back into the space Daylighting controls Automatic or manual controls dim or turn off electric lighting when there is sufficient daylight present Refer to Section 7 2 1 3 Control in Daylighted Are
216. ow 0 86 SOLUTION 3 Using equation 1 17 the total solar heat gain through the glazing is Qs 0 6 x 4 5 x 111 3 x 0 86 258 4 W 12 1 6 Heat Flow through Fenestration Fenestration is an architectural term that refers to the arrangement proportion and design of window skylight and door systems within the building envelope Fenestration components include a combination of glazing material either glass or plastic framing mullions dividers and opaque door slabs external shading devices internal shading devices and integral between glass shading systems Energy flows through fenestration is a complex heat transfer phenomenon where heat flow is simultaneously taking place through conduction convection and radiation Heat transfer through fenestration components of the building envelope combines the following processes e Conductive and convective heat transfer caused by the temperature difference between outdoor and indoor air e Net long wave above 2500 nm radiative exchange between the fenestration and its surrounding and between glazing layers e Short wave below 2500 nm solar radiation incident on the fenestration product either directly from the sun or reflected from the ground or adjacent objects Fig 36 Heat Balance for a Sunlit Glazing System to ti OUTOOOR TEMP INDOOR TEMP INCOMING SOLAR INWARD HEAT FLOW BY RADIATION CONVECTION AND RADIATION INCIDENT ANGLE 6 REFLECTED S
217. pant and motion sensors automatic or manual daylighting controls and astronomical time switches automatic switches that adjust for the length of the day as it varies over the year 92 Lighting Control It is worthwhile to determine the amount of local vs central control that is needed from the lighting control system Manual lighting controls range from a single switch to a bank of switches and dimmers that are actuated by toggles rotary knobs push buttons remote control and other means Manual controls can be cost effective options for small scale situations However as the lighting system grows automated systems become mote cost effective and are better at controlling light Manual controls often waste energy because the decision to shut off the lights when they are not needed is based entirely on human initiative The following issues should be kept in mind while designing controls e Install a separate control circuit for each lighting element that operates on a distinct schedule Where light fixtures are needed in a predictable variety of patterns install programmable switches Install lighting controls at visible accessible locations Where lighting is needed on a repetitive schedule use time clock control Install occupancy sensors in bathrooms conference rooms and other spaces not in constant use 7 2 1 1 Automatic Lighting Shutoff Although there is no simpler way to reduce the amount of energy consumed by lig
218. perture vertical fenestration a measure of the amount of daylight that enters a space through vertical fenestration It is the ratio of the daylight window area times its visible light transmission plus half the vision glass area times its visible light transmission and the sum is divided by the gross wall area Daylighted window area is located 2 2 m 7 ft or more above the floor and vision window area is located above 1 m 3 ft but below 2 2 m 7 ft The window area for the purposes of determining effective aperture shall not include windows located in light wells when the angle of obstruction a of objects obscuring the sky dome is greater than 70 measured from the horizontal nor shall it include window area located below a height of 1 m 3 ft See also daylighted area total watts of input power including the ballast expressed in lumens per watt Obstructign Efficiency performance at a specified rating condition N Angle Efficacy the lumens produced by a lamp ballast system divided by the Remittance the ratio of the radiant heat flux emitted by a specimen to that emitted by a blackbody at the same temperature and under the same conditions Enclosed building a building that is totally enclosed by walls floors roofs and openable devices such as doors and operable windows CXXXIV Energy the capacity for doing work It takes a number of forms that may be transformed from one into another such as thermal he
219. ply air diffuser Turn fans off Close outdoor air dampers Install system controls to reduce cooling heating of unoccupied space 2 Reduce HVAC operating hours Turn HVAC off earlier Install HVAC night setback controls Shut HVAC off when not needed Adjust thermostat settings for change in seasons Adjust the housekeeping schedule to minimize HVAC use Schedule off hour meetings in a location that does not require HVAC in the entire facility Install separate controls for zones Install local heating cooling equipment to serve seldom used areas located far from the center of the HVAC system Install controls to vary hot water temperature based on outside air Use variable speed drives and direct digital controls on water circulation pumps motors and controls Adjust areas that are too hot or too cold Adjust air duct registers Use operable windows for ventilation during mild weather Use window coverings blinds awnings etc to cut down on heat loss and to avoid heat gain Use light colored roofing and exterior wall material with high reflectance to reflect heat Incorporate outside trees to create shade Install ceiling fans Create zones with separate controls 4 Reduce unnecessary heating or cooling Set the thermostat higher in the cooling season and lower in the heating season Allow a fluctuation in temperature usually in the range of 68 to 70 F for heating and 78 to 80 for cooling Adjust heating and coolin
220. pressor fan or pump Speed control is obtained by adjusting the frequency of the voltage applied to the motor This approach usually saves energy for variable load applications 66 5 2 4 Piping and Ductwork 5 2 4 1 Pipe Insulation To minimize standby losses the ECBC requires that pipelines for the entire hot water system including the storage tanks must be insulated The required R value for heating and cooling systems is based on the operating temperature of the system as shown in the tables below Insulation Piping insulation exposed to weather is required to be protected by aluminum sheet metal painted canvas or plastic cover Cellular foam insulation must also be protected in this manner or be painted with water retardant paint ECBC 5 2 4 1 Ductwork should also be protected in the same manner Condensing moisture can cause many types of insulation such as fiberglass to lose their insulating properties or degrade Insulating ducts in unconditioned spaces and outside the building is the first portion of the duct requirements within the ECBC The R value is measured on a horizontal plane in accordance with ASTM C518 at a mean temperature of 24 C 75 F at the installed thickness All insulation values are shown on ECBC Table 5 2 reproduced below in Table 22 A list of some typical material meeting or exceeding the recommended R values is shown inTable 233 All supply ductwork located outside the building must b
221. propriate ECBC requirements Additional information may be requested if needed to verify compliance The compliance forms and worksheets are provided with this Guide and are intended to facilitate the process of complying with the Code These forms serve a number of functions e They help a permit applicant and designer know what information needs to be included on the drawing e They provide a structure and order for the necessary calculations The forms allow information to be presented in a consistent manner which is a benefit to both the permit applicant and the enforcement agency e They provide a roadmap showing the enforcement agency where to look for the necessary information on the plans and specifications 12 e They provide a checklist for the enforcement agency to help structure the drawing check process e They promote communication between the drawings examiner and the field inspector e They provide a checklist for the inspector 3 4 2 Supplemental Information In this new and emerging market for energy efficient buildings and building components it can be difficult at times to locate and secure the best products for use in construction This may be because they are not available locally or are too expensive for the owner s budget It may also be a significant task to determine the energy efficiency properties of products that are not clearly labeled The ECBC contains default values that can be used for typical products a
222. r Demand or tankless or instantaneous water heaters provide hot water only as it is needed They don t produce the standby energy losses associated with storage water heaters which can save you money What are standby losses These losses account for energy lost while storing heated water This includes any heat losses through the water heater tank wall fittings and flue plus any pilot light energy Standby loss depends on the design and insulation of the water heater as well as the 86 difference between the temperature of the water and that of the air around the tank Water heating energy can be reduced by decreasing standby losses How do demand water heaters work Demand water heaters heat water directly without the use of a storage tank Therefore they avoid the standby heat losses associated with storage water heaters When a hot water tap is turned on cold water travels through a pipe into the unit Either a gas burner or an electric element heats the water As a result demand water heaters deliver a constant supply of hot water You don t need to wait for a storage tank to fill up with enough hot water However a demand water heater s output limits the flow rate Electric Demand Water Heater Heating Unit is mataika i n dose prodmity Hot n Power Source 110 or 220 volts Distribution systems for water heater Standard Standard system without any pumps for distributing hot water
223. r moves a heat transfer fluid or refrigerant such as ammonia and fluorinated hydrocarbons between the evaporator and the condenser The pump forces the refrigerant through the circuit of tubing and fins in the coils The liquid refrigerant evaporates in the evaporator coil pulling heat out of indoor air and thereby cooling the space The hot refrigerant gas is pumped into the condenser where it reverts back to a liquid giving up its heat to the air flowing over the condenser s metal tubing and fins Because the condenser is the heat rejection unit so it should be located in such a manner that the heat sink is free of interference from heat discharge of other equipment for optimum performance Type of Air Conditioners The most common types of air conditioners are room unitary air conditioners split system central air conditioners packaged air conditioners and central air conditioners The unitary and packaged systems offer localized solutions for a building s heating and cooling needs These systems are typically appropriate for smaller single zone buildings Compared to local HVAC systems in most conventional commercial buildings a central HVAC will be able to provide better thermal comfort and meet energy efficiency parameters Local HVAC Systems Room Unitary and split air conditioners Room air conditioners cool rooms rather than the building and provide cooling only when needed Room air conditioners are less expensive to operat
224. r portions thereof Control to regulate the operation of equipment Control device a specialized device used to regulate the operation of equipment Constant Volume System A space conditioning system that delivers a fixed amount of air to each space The volume of air is set during the system commissioning Cool roof a property of a surface that describes its ability to reflect and reject heat Cool roof surfaces have both a light color high solar reflectance and a high emittance can reject heat back to the environment Daylighted area the daylight illuminated floor area under horizontal fenestration skylight or adjacent to vertical fenestration window described as follows CXXXII Effective Aperture Visible Light Transmittance x Window to Wall Ratio EA VLT x WWR Horizontal Fenestration the area under a skylight monitor or sawtooth configuration with an effective aperture greater than 0 001 0 1 The daylighted area is calculated as the horizontal dimension in each direction equal to the top aperture dimension in that direction plus either the floor to ceiling height H for skylights or 1 5 H for monitors or H or 2H for the sawtooth configuration or the distance to the nearest 1000 mm 42 in or higher opaque partition or one half the distance to an adjacent skylight or vertical glazing whichever is least as shown in the plan and section figures below Vertical Fenestration the floor area adjacent to side apertur
225. r each area in Column C by the square meter of each area in Column D below The total allowed watts value is determined by adding the values in Column E 17 000 watts Tenant Area or Building or Area Type Entire Building Portion of Building wats par ma wats per m2 Bor Ox Corridor Restroom N A 1 000 800 Support Areas Total Allowed Watts 17 000 Note that in the above example only Column B or Column C can be used to determine the allowed lighting power qualify project Do not use more than one column Building or Allowed Space Watts 7 3 4 Installed Interior Lighting Power To determine the installed interior lighting power the calculation must include all power used by the luminaires including lamps ballasts current regulators and control devices except as specifically exempted in the ECBC However if two or more independently operating lighting systems in a space ate controlled to prevent simultaneous user operation the installed interior lighting power calculation must be based solely on the lighting system with the highest power 7 3 4 1 Luminaire Wattage The ECBC requires that luminaire wattage be incorporated into the installed interior lighting power calculation as follows e For incandescent luminaires with medium base sockets which do not contain permanently installed ballasts the wattage used must be the maximum labeled wattage of the luminaires e For luminaires containing permanently installed
226. r scored squared efficiency motor with 5 percent slip on a given load rotates at 1710 rpm while an energy efficient motor might run the same load at 1750 rpm with 3 percent slip This will increase the output of the driven device but increase input ow Sub serfbing equations 2 and2 inta 1 gias us power much mote because of the cube law In this case See Figure 27 e The rotational speed of the motor and fan or pump increases by 2 3 percent 40 rpm 1710 rpm e Flow rate increases by 2 3 percent by fan pump laws e Average fluid speed increases by 2 3 percent and Power required by the fan or pump increases by 7 1 percent 1 023 cubed Improved motor efficiency will offset some of this increase but if speed is not corrected to be the same with the energy efficient motor as with the standard motor the efficiency gained may be more than offset by the load s higher power consumption Cube Law The motor shaft is connected to the load is crucial in determining cube law applicability In general the cube law applies only to loads in which required torque increases with speed because of fluid friction Consider a fan moving air through a simple duct loop The fan is essentially doing no physical work other than overcoming the friction of the duct loop so the power to drive the fan is the product of fan efficiency times flow times pressure times a constant to make units consistent Assuming that fan efficiency is
227. r than 0 085 kWh C m FAQs 2 Opaque Elements What is Rigid Board Insulation Rigid board insulation is commonly made from fiberglass polystyrene and polyurethane It comes in a variety of thicknesses and has a high insulating value approximately R 4 to R 8 per inch This type of insulation is used for flat or low sloping roofs on basement walls on exterior walls as perimeter insulation at concrete slab edges and in cathedral ceilings Sometimes rigid foam insulation boards are used to insulate the interior of masonry walls How is Rigid Board Insulation installed To install boards wood furring strips should be fastened to the wall first These strips provide a nailing base for attaching interior finishes over the insulation Fire safety codes require that a gypsum board finish at least 1 2 inch thick be placed over plastic foam insulation and attached to the wood furring strips or underlying masonry using nails or screws Use recommended adhesives to bond rigid foam insulation boards to the walls of an unventilated crawlspace Because the insulation will be exposed be sure to check the local fire codes and the flame spread rating of the insulation product For exterior applications rigid board insulation must be covered with weatherproof facing Since below grade exterior insulation allows a path for termites check with local code officials to determine whether such insulation is acceptable Leave a 6 inch gap between the insul
228. r than with fixed devices Use movable devices that are automatically controlled via a sun sensor for the best energy savings Source Lawrence Berkeley National Laboratory 1997 Tips for Daylighting with Windows Available from http windows lbl cov daylighting designeuide dlg pdf Vertical Standard horizontal louvers overhang or tins tor east and especially west facades Drop the Slope it down edge for less for less projection projection Substitute Use louvers in louvers place of for the solid solid dropped overhang for edge to let moe in more dittuse light aht while still shading i Break up an overhang for less projection 48 FAQ 4 What is a Light Shelf A light shelf is a horizontal light reflecting overhang placed above eye level with a transom window placed above it This design which is most effective on southern orientations improves daylight penetration creates shading near the window and helps reduce window glare Exterior shelves are more effective shading devices than interior shelves A combination of exterior and interior will work best in providing an even illumination gradient Since luminance ratio brightness is a major consideration in view windows it is often wise to separate the view aperture from the daylight aperture This allows a higher visible transmittance glazing in the daylight aperture if it is out of normal sight lines Since the ceiling is the most important
229. ra Ves GO chs calm eer Mn E A Trey er Mert rene rece verter er on ee tire oP cxliii CLIMATE ZONE MAP OF INDIA ceccocoooocooococooocoocooooocoocooococoococoooocoocoocooooooooooo CXLV A Cia AO e E E E T E cxlv SUPPLEMENTAL MATERIALS Cece rere r cece ce cec reese ee eee eee sere sesesesesesesesesesesesesesesesece CLI 12 1 HEAT TRANSFER FUNDAMENTALS AND CALCULATIONS qe eeseeeeeeseneeeeees cli TANT Hat PIO MED ast S anena E E T A A cli E2 Theat Plow throu lt Condic Hon seen E E E E N S cliii 121 Heat Fow Thtouch COmmectOn niei arine ER a E ENEE clvii 120A Heat ITranster Throch Radiation seia a a ea iinleraeladss clix S Dolke err 7h e E E E eee ee clxi Lo Her How aro ue h Pen stalone EAE OES clxii 12 1 7 Thermal Transmittance U FACTOR of Fenestrtation sssssesesresrssereseresrseseesess clxiv 12 1 8 Estimation of Heat Transfer Through Computer Based Tools sesser clxvi REFERENCE S cecceccocooooocoococoooocoooocooocoocooooocoococoocoocoocoocoocoococoocoocoocooooooooooo CLXVI I LIST OF TABLES Table 1 Equipment Requirements for Building Additions sseeeeersrsrrrreeeesrsssssseeeeesssrseeeeeessssseeeeeersrrrreeeeeeerrrrerrrreeeeeeeseee 8 Table 2 Basic Concepts for Energy Efficient Building Design eoe isie hissiin isien aisiak 16 Table 3 Comfort Requirements and Physical Manifestations in Buildings seessesserrrrereeesesrrreeeeeeeeseeeeeeeerssseeeeeeeerseeeeess 18 Table 4 Roof Assembly U Factor and Insulation R Value Requirements eeeeeeeetteessesrssss
230. ral sectors National estimates show that the building energy use in India is increasing by over 9 annually which greatly outpaces the national energy growth rate of 4 3 It is projected that the commercial building sector alone will grow at 7 annually up to the year 2030 in India Currently India has only 200 million square meters of installed base but by 2030 it is expected that 8 690 million square meters of additional commercial space will be constructed This trend has already begun to strain the power sector with energy shortages of over 11 3 in peak demand and a 7 supply deficit leading to power cuts and rolling blackouts that are endemic in most cities and towns of the country Buildings are typically designed to last 50 to 100 years so their energy performance can have enduring effects An improved energy efficiency scenario translates into reduced operating costs and a reduced demand for energy Energy cost ranges between 10 to 15 of operating income in commertcial buildings Further energy consumption studies conducted in several office buildings hotels and hospitals indicate an energy savings potential of 20 to 50 in end uses such as lighting ventilation and cooling building services operation etc This represents a vast untapped saving potential attributable mainly to lack of an effective delivery mechanism for energy efficiency with tangible financial benefit to the individual as well as the nation Apart from burdening our
231. rduons to Pastior obi Ice thal Sac ssiri eer arte te erry een er eters 8 a Ooa a e O e eer A A A P A E E E A A 10 3 3 a a R GN TAN NS a E E EO EENEN 12 3 4 Corni N e DO A a T E E E 12 SE E E e E E E O E E A TT 12 SP mmmere el oe leieuleale ieabdepe vacia ON eoa E 13 4 BUILDING ENVELOPE Cee e mere ere cere re rere recess eres esses ee eee eee eeseseseseseresesesesereseseseseces 14 4 1 A a A A E AANE AA 14 4 2 Mandata Regue iE cei ninii E EEEE A E T E 21 A E a a E E E E A AE O IE E EIA A AA E 21 De AGS sO soa cecctaccan sess eai EEE A 24 4 2 3 Building Envelope a tosses sista oa cergenrtes nas ben satan nceeesd aestposacobeees asst aestbatates 25 4 3 Pe TE 0 a N ne ees 26 Al RODI etp a A E N AE EET EOE E OOTTE 26 De TE S a EA E 32 Ao Veruca Feneco ON E rer eer R A 40 o O EA A E ta eden A A E O T 51 4 4 Paldini Pavelope Trade OU OPHION creii R E A 53 5 HEATING VENTILATION AND AIR CONDITIONING tttereeereeeeserereererereresrereees 54 5 1 OM e asec E I sce cso cee svn oe ea ag ceo ccs ea coisas nse ese wats ee aba AA seen E nent 54 5 1 1 54 5 1 2 54 5 2 Mandato ROGUES HCI S apse senseless E E O nim teninda lap 61 ae N E A a nereemc rrer rene try rere Cerne mr nrr en tne rrr rere en mn Ne Terr tt 62 Daa MiumunrEoupmecit al solellc ol elles seriearen eia ren teeter ren ert terre avrer 63 ar LORO E E A E seattle estetp ten ann EE OEEO TT N 64 PA EE lt lt e E DI a domme eet E E E E A E A E ees 67 Oe T a E E E O A 69 EV E a E hc A E E A E E E E E E
232. re valves or loops of pipe that allow water to flow into the water heater tank but prevent unwanted hot water flow out of the tank The valves have balls inside that either float or sink into a seat which stops convection These specially designed valves come in pairs The valves are designed differently for use in either the hot or cold water line Heat traps can help save energy and cost on the water heating bill by preventing convective heat losses through the inlet and outlet pipes 84 Types of Water Heaters Storage Gas A gas water heater designed to heat and store water at less than 180 F Water temperature is controlled with a thermostat Storage gas water heaters have a manufacturet s specified storage capacity of at least two gallons and less than 75 000 But h input Large Storage Gas A storage gas water heater with greater than 75 000 Btu h input Storage Electric An electric water heater designed to heat and store water at less than 180 F Water temperature is controlled with a thermostat Storage electric water heaters have a manufacturet s specified capacity of at least two gallons Storage Heat Pump An electric water heater that uses a compressor to transfer thermal energy from one temperature level to a higher temperature level for the purpose of heating water It includes all necessary auxiliary equipment such as fans storage tanks pumps or controls EFs for heat pump water heaters are found in the Energ
233. rect amount of airflow and refrigerant The distribution system must be appropriately sized There must be easy access to the coil for maintenance The duct system must be sealed for air leaks The duct system must be insulated What is Duct Leakage Duct leakage generally refers to holes or unsealed or unfastened seams in air ducts and is typically described in any of three different ways 1 as the fraction of the flow through the HVAC equipment that is lost 2 as an equivalent hole size and 3 as a leakage flow at some reference pressure with the latter two often being normalized by either the surface area of the ductwork or the conditioned floor space What are Sealed Ducts Sealed ducts have appropriately installed joints and connections to minimize leakage of conditioned air Air leakage cannot be seen by the naked eye therefore diagnostic testing is needed to verify leakage and by using complying tapes mastics and mechanical fasteners or aerosol sealant leaks can be closed Are insulated ducts the same as sealed ducts No insulated ducts are not necessarily sealed ducts Care should be taken by the installer to seal the ducts prior to insulation 5 2 5 System Balancing 5 2 5 1 General System balancing is a process for measuring the performance of a HVAC system and for providing the occupants with a comfortably conditioned space Balancing the air or water based HVAC system of buildings will make it more
234. rements e Confirmation of the simulation programs which can be used for this process of energy simulation to show compliance e lt Any local amendments to the ECBC which need to be followed e Check whether the climate data and the weather file which is available for the building site is accepted to the authorities e What utility rate schedules are approved for calculating energy costs in this jurisdiction 9 2 2 Step 2 Comply with the Mandatory Provisions All the mandatory requirements of the ECBC code must be met by the building The mandatory provisions of building envelope HVAC service hot water and pumping lighting and electrical power are provided in the respective chapters of the code and should be complied by the proposed building Chapter 4 2 5 2 6 2 7 2 and 8 2 of the ECBC deals with the mandatory provisions which are to be fulfilled by the building It may be noted that even if whole building performance approach is adopted for compliance of ECBC mandatory requirements must be followed Mandatory requirements are not to be confused with requirements for prescriptive approach 9 2 3 Step 3 Create the Standard design simulation model The standard design simulation model is created by following Section 11 Appendix B Whole Building Energy Performance of the ECBC Once the model has been created the energy consumption of the standard design building is calculated using the simulation model Before commencing the
235. rigerant flow VRF refers to the ability of the system to control the refrigerant amount flowing to each of the evaporators This enables the use of many evaporators of dif fering capacities and configurations individualized comfort control simultaneous heating and cooling in different zones and heat recovery from one zone to another The energy efficiency of VRE systems derives from several factors VRF technologies provide very good part load performance by limiting conditioning to only those rooms that are occupied thereby making it an effective energy conservation strategy The duct losses are also essentially eliminated through this technology which are often estimated to be between 10 20 of the total airflow in a ducted system A 9 P L E i iy A g f F Typical VRF Configuration in an Office Building Sources Stein B Reynolds J Grondzik W Kwok A 2005 Mechanical and Electrical Equipment For Buildings 10 Ed John Wiley Sons Inc Goetzler W 2007 Variable Refrigerant Flow Systems ASHRAE Journal 49 4 T ENERGY CONSERVATION FOR HVAC SYSTEMS 1 Reduce HVAC system operation when building or space is unoccupied Reduce HVAC operating hours to reduce electrical heating and cooling requirements Eliminate HVAC usage in vestibules and unoccupied spaces Minimize direct cooling of unoccupied areas by turning off fan coil units and unit heaters and by closing the vent or sup
236. ring directing glass All of these measures A with in the cutoff distort or impair the view so they are range is blocked i m bo contol clare typically placed above standing height Prismatic Glazing The typical light shelf uses a reflective Conventional upper surface to direct sunlight from the glazing window wall deeply into the interior of a room Various means are available to increase the effectiveness of light shelves including prismatic aluminized films compound geometries designed to match particular solar altitudes and movable systems that can be tuned to match the season or change the depth of sunlight penetration Another variation on the theme is the between the panes light shelf that uses the same principles of reflection but protects the elements between two panes of glass and can be manufactured in high volumes 7 2 1 5 Additional Control The following specialty lighting spaces are required to have a control device that separates lighting control from that of the general lighting e Display accent lighting greater than 300m2 3 000 ft2 e Case lighting in display cases greater than 300m2 e Hotel and motel guest rooms and guest suites these shall have a master control device at the main room entry e Task lighting e Non visual lighting such as plant growth and e Demonstration lighting equipment controls accessible only to authorized personnel FAQs 16 Lighting Controls Q An open office
237. rmal Conductivity k Thermal conductivity is the time rate of steady state heat flow through a unit area of 1 m thick homogeneous material in a direction perpendicular to isothermal planes induced by a unit 1K temperature difference across the sample 3 Thermal conductivity k value is expressed in W m K Btu h ft F or Btu in h ft F It is a function of material mean temperature and moisture content Thermal conductivity is a measure of the effectiveness of a material in conducting heat Specific Heat Cp Specific heat capacity also known as specific heat is the measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval It is expressed in KJ kg K Thermal Conductance C Thermal Conductance is the rate of heat flow through a unit surface area of a component with unit 1 K temperature difference between the surfaces of the two sides of the component It is the reciprocal of the sum of the resistances of all layers 16 composing that component without the inside and outside air films resistances It is similar to thermal conductivity except it refers to a particular thickness of material Thermal conductance C value is expressed in W m2 K Btu h ft2 F Thermal Resistance R Thermal resistance of insulation is a measure of the effectiveness of thermal insulation to retard the heat flow It is a function of material thermal conductivity thicknes
238. rom the hotter surfaces to the detached colder ones through any transport medium like empty space Table 2 describes basic energy efficient building design strategies to manage heat flow in buildings Table 2 Basic Concepts for Energy Efficient Building Design Wall Minimize conduction Use insulation with Use insulation with Use material with losses low U value low U value low U factor Use prefabricated Reduce air leakage Reduce air leakage windows and seal the and use and use vapour barrier joints between windows and wall Minimize convection losses and moisture penetration Use glazing with low Solar Heat Gain Coefficient SHGC Use shading devices Use light coloured Use light coloured coating coating with high reflectance with high reflectance Minimize radiation losses Source ECBC Tip Sheet Building Envelope The heat flow through the opaque elements of the building envelope like the walls roof or the floor is estimated by the thermal properties of building materials such as density thermal conductivity specific heat thermal conductance thermal resistance R Value and thermal transmittance U Value The thermal properties of common building materials are available in Appendix C of the ECBC Thermo physical properties of building materials Density p This is defined as the ratio of the mass of the substance to the volume of the substance at atmospheric condition Density is expressed in kg m The
239. roposed energy budget is no greater than the allowed energy budget the building complies Figure 2 Design Process for the Whole Building Performance Method Make Energy Budgets mm Changes ta equal non compliant the proposed design Computer Stamiird Design Model ECDC TOT pares Proposed Design actual design emp ewes prescriptive the Energy requirements Budgets Energy Budgets egual ECEE a The biggest advantage of using this approach is that it enables the design build team to make trade offs between building systems in order to identify the most cost effective and energy efficient design solution For instance the efficiency of the indoor lighting system might be improved in order to justify fenestration design that does not meet the prescriptive envelope requirements As long as total energy use considering all installed components does not exceed the allowed budget the trade off is acceptable With either the prescriptive or the performance methods compliance can be only be achieved by meeting the general and mandatory provisions of each technical section Then compliance can be achieved when the total energy consumption of the proposed building is demonstrated to be less than the consumption of a building that complies with the prescriptive requirements of the code NOTE For a detailed description of the computer simulation process and details please refer to the Energy Simulation Tip Sheet which can b
240. s Please see Chapter 9 for computer simulation techniques for ECBC compliance under the Whole Building Performance Method REMARKS The above mentioned examples illustrate simple calculations that impact total heat transfer from buildings Suppose we know that the total heat load of a building is 4168 7 W 4 2 kW Now the problem facing a designer is to make sense of this quantity As the total heat gain rate is positive it represents the total heat entering the building How does 4 2 kW translate practically Let us consider it from two angles e The COP of a standard window air conditioner of 1 5 tons cooling capacity is about 2 8 So the power required is 1 5 kW e 4 2 kW 2 8 Suppose the machine were to be used for 8 hours a day then it would consume 12 kWh per day 1 5 kW x 8 hours 12 or 12 units One kWh is equivalent to one unit of electricity supplied by the power company At a rate of Rs 4 per unit expenses would amount to Rs 48 per day CLXVI 3 REFERENCES References 1 Handbook on Energy Conscious Buildings 2006 Nayak amp Prajapati 2 Steve Meder Course Documents ARCH 316 School of Architecture University of Hawaii at Manoa 3 Morrison F 2004 What s up with Cooling Tower ASHRAE Journal 46 7 4 Stein B Reynolds J Grondzik W amp Kwok A 2005 Mechanical and Electrical Equipment for Buildings 10 Ed John Wiley amp Sons Inc 5 Goetzler W 2007 Variable Refrigerant Flow
241. s R value thermal resistance the reciprocal of the time rate of heat flow through a unit area induced by a unit temperature difference between two defined surfaces of material or construction under steady state CXXXVIII conditions Units of R are m C W h ft F Btu For the prescriptive building envelope option R value is for the insulation alone and does not include building materials or air films Readily accessible capable of being reached quickly for operation renewal or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders chairs etc In public facilities accessibility may be limited to certified personnel through locking covers or by placing equipment in locked rooms Recirculating system a domestic or service hot water distribution system that includes a close circulation circuit designed to maintain usage temperatures in hot water pipes near terminal devices e g lavatory faucets shower heads in order to reduce the time required to obtain hot water when the terminal device valve is opened The motive force for circulation is either natural due to water density variations with temperature or mechanical recirculation pump Reflectance the ratio of the light reflected by a surface to the light incident upon it Resistance electric the property of an electric circuit or of any object used as part of an electric circuit that determin
242. s Specification ssrtesessseeeeteessseeseeesseeeeeeees 63 Table 19 Power Consumption Rating tor Split Air Conditioner s seinimnconwnteuaienetueionasiduunieneinimnias 64 Table 20 Capacity Rating Test for Packaged air Conditioners Specification sssssssseeseesessssseeteeeeesessssneeeeeeeeeneeseees 64 FT Ue E E ect sss pve toda E A ANENE ASEESSA AT 64 Table 22 D ctwork alla Gi ae Acadiana eee es 67 Table 23 Sample R Values for Duct Insulation Materials sccccsssesssssssseeeeeeeessseeeeeeeeseseeeseeseeeeeseens cesses saneeeeees 68 AI lols 4c Gea enya nema ee O cate gtr cr an oneal ero reeemnei ents 68 Table 16 Standardized Conditions for analysis of Long Term Energy Savings Clause 6 7 ssssreseeseeseeeeeseeseeeeeees 84 ET led eT a eta aera cece een oes accent tte tet ce ee esencsions 98 Table 35 Activity eeeseeessssssssrrsssssseseseeeeeeeeeeseseesrssssserrrrrreeeeeeeeeeeeeeersssrsssrrsrseteeeeeeeeeeresesessrssereeeeeeeressssssssssetteeeeeeeeeeeees CXX X Table 46 C nstructiONisrssisisrersressristsvsirriatets dsvst soitti Ev EsEs spr PERENNES ADRE ESSEEN SESER ETERS EIRE eae CXXX T O E E A EE E E E EA oo Tle OG Lighting ssnnvenetesasavasntartnascadnavhasicasa a a aR aisha vearsarusaecamnds Cxxxi lable 79 HVAC serere n ener AA S EEEE EERE S REEERE AES EEEE EE EAEE S CXXX Table 8 Climate Zone of the Major lidian Cities ererieersitrirririritiisisrrktritt ss Coti s ts AE CERESE KEN ESE EEK ESER EA ENAN S EERE REREIS
243. s edge of glass and frame respectively Aris the area of the fenestration product s rough opening in the wall or roof less installation clearances When a fenestration product has glazed surfaces in only one direction typical windows the sum of the areas equals the projected area Skylights greenhouse garden windows bay bow windows etc because they extend beyond the plane of the wall roof have greater surface area for heat loss than a window with a similar glazing option and frame material consequently U factors for such products are expected to be greater NOTE e U Values for fenestration products are sometimes provided for the entire glazing assembly glass frame and shading device or can be provide for the glazing type only If U values for only the glazing type have been provided the overall U factor needs to be calculated by including the transmittance values for the frame and the shading device if any Additionally if U values for a eg and fare given separately the overall U factor for the glazing needs to be determined by using equation 1 19 e Representative U Factors for Various Fenestration Products in W m K are available in Chapter 31 Table 4 2005 ASHRAE Fundamentals The Visible Transmittance and Solar Heat Gain Coefficient SHGC for common glazing and window systems are available in Ta ble 13 of 2005 ASHRAE Fundamentals These values are also available from ECBC Table 11 for representative Unrated Vertical Fen
244. s and density A material with high thermal resistivity low thermal conductivity is an effective insulator Thermal resistance R value is expressed in m K W h ft F Btu Thermal Transmittance U Thermal transmittance is a rate of heat flow through a unit surface area of a component with unit 1K temperature difference between the surfaces of the two sides of the component It is the reciprocal of the sum of the resistances of all layers composing that component plus the inside and outside air film resistances It is often called the Overall Heat Transfer Coefficient U value and is expressed in W m K Btu F ft h Example 2 Heat Transfer Processes Occurring in a Wall Consider a wall having one surface exposed to solar radiation and the other surface facing a room Of the total solar radiation incident on the outer surface of the wall a part of it is reflected to the environment The remaining part is absorbed by the wall and converted into heat energy A part of the heat is again lost to the environment through convection and radiation from the wall s outer surface The remaining part is conducted into the wall where it is partly stored thereby raising the wall temperature while the rest reaches the room s interior surface The inner surface transfers heat by convection and radiation to the room air raising its temperature Heat exchanges like these take place through opaque building elements such as walls and roofs Additional
245. s and improve voltage regulation at the load PFC is normally achieved by the addition of capacitors to the electrical network which reduce the burden on the supply All current will cause losses in the supply and distribution system A load with a power factor of 1 0 results in the most efficient loading of the supply and a load with a power factor of 0 5 will result in much higher losses in the supply system The ECBC requires that all electrical supplies 110 FAQs 18 Power What are some of the benefits of Power Factor Correction Reduced power consumption Reduced electricity bills Improved electrical energy efficiency Extra kVA availability from the existing supply Reduced I2R losses from transformer and distribution equipment Minimized voltage drop in long cables What are some ways to correct the power factor Minimize operation of idling or lightly loaded motors Avoid operation of equipment above its rated voltage Replace standard motors as they burn out with energy efficient motors Even with energy efficient motors however the power factor is significantly affected by variations in load A motor must be operated near its rated capacity to realize the benefits of a high power factor design Install capacitors in your AC circuit to decrease the magnitude of reactive power exceeding 100 A 3 phases shall maintain their power factor between 0 95 lag and unity at the point of connection ECBC 8 2 3 Cube Law
246. serins rrr EEEE EEA 63 Figure 16 The Components of an Economizet s cccsssccssssceeessceesssceessecessscceensceesnsceescceescceesneceessesessaeesseeeseeeesneeeesnsees 13 Figure 17 Examples of Solar Water Heating Systems cc ccsscssssssesseeesseeesscessecessceesseesssecesseensseeesecesecsesesesesseeessesseees 83 Prie al ters Silke s gent rere ere en Tener TT rrr eaneT Poe eran ET ere TERT ree TT R eee ere re trey arrver Terr errr eereren Terr ry Ter 89 Figure 199 Heat Trap Elements s c s2scessccesctssesessacnsiscecasaceantahsicicsdessvossndadssnesdedesanedeascoasacdsantdabssacnsndedsaonedanddavidbestdascssscaess 89 Figure 204 Lighting Summary Worksheet from ECBC Appendix G ssssssssssssserssesssesserssersorssorssesseessersersrorsorssserersers 100 Figure 21 Ground Floor Plan of the Case Study Building s sssessssressressresssssssesssnsssetssessresssrsssenerressrarssesrrrresrtnrssnissesssa CXX Teure 22 Climate Zone Map esien anA AEE EEA cxlviii Figure 23 Heat exchange processes between a building and the external environment sssssessrersssrrersssererrsseererssers cliii Figure 24 Heat exchange processes between a human body and the indoor environment essesessersersserrsrrrerrserssres cliii Figure 25 Nature of heat flow through building materials and air spaces cccsscessscessscesseeesseeessceesseeeseeesseceseeeneees cliv Xl PURPOSE he Energy Conservation Building Code ECBC provides minimum standards for energy
247. seson e e A eamaiaen 103 Eoy Esener Lohta POWE ernan a T E museca seescgetacnel yinatine 104 ELECTRICAL POWER See 105 8 1 Generale Ne Tree eA EO ety EAU eye N A eC yet ere 105 8 2 Mandator REEE 11S ae cabins cuentas T T a 105 Oe A ON 16 a R a a a TE 105 Gaa EEEO MOO mirra A E R dled 107 Gar POWT Pactor EOL CCCI uaa a A a ese aa 110 6 24 Check Metern and Monitoring asise ea E E OEA 113 Sa Power Deribatu on Sy Steins E aA EE ER 116 ENERGY SIMULATION cecccooooooooocoocoocoocoocoocoocoococoocoocoocooooocooooooooooooooooooooo CXVII 9 1 OS el a EE E T EE T E E A th E E E A E E T cxvii 9 2 Casestudy Duildime DescHipio tiroir tee te een er Teta AE reer Meret er eee ey arora cxvii 9 2 1 step Confirmation from the Local authorities s esssesseseserserereseresrsesrsrsrsrsrsrsrsrerss CX1xX 922 Step 2 Comply with the Mandatory Provisi GiGi czcsie secaod a custonesnteotaasteendaceessetustaacense CX1X 9 2 3 Step 3 Create the Standard design simulation model oo eeeeseeceeeeeeeeeeeeeeeeeees CXIX 9 2 4 Step 4 Create the Proposed design Simulation Model oe eeseeeseeeeseeeeeeeeeeeees cxxiii O29 Step 5 Completing and comparing the models sssesesessesesesesssresrsrsrersrrreresseereees CXXVil 9 2 6 Step 6 Documentation of the Compliance Process eee esseeeeereeeeeeeteeseeeeees CXXVil ECBC DEFINITIONS ABBREVIATIONS AND ACRONYMS 000 ssssseeeeeeeeeeees CXXXI WE Oene alere AO A E CXXX U2 DeUMAON a a T error A T T E CXXX1 1O ADDEN aons ela e
248. sing the relationship between visible light and the size of the window is the effective aperture method The effective aperture EA is defined as the product of the visual light transmittance and the window to wall ratio The window to wall ratio WWR in this case is the proportion of window area compared to the total wall area where the window is located i e that particular elevation For example if a window covers 25 square feet in a 100 square foot wall then the WWR is 25 100 or 0 25 For a given EA number a higher WWR larger window results in a lower visible transmittance Example WWR 0 5 half the wall in glazing VLT 0 16 EA 0 08 Or WWR 0 70 VLT 0 11 for same EA of 0 077 Typically lowering the visible light transmittance will also lower the shading coefficient but you must verify this with glazing manufacturer data since this is not always the case 4 3 4 Skylights A skylight is a fenestration surface having a slope of less than 60 degrees from the horizontal plane Other fenestration even if mounted on the roof of a building is considered vertical fenestration Skylights can be installed into a roof system either flush mounted or curb mounted including site built In order to create a positive water flow around them skylights are often mounted on curbs set above the roof plane However these curbs rising 6 to 12 inches 15 to 30 centimeters above the roof create additional heat loss surfaces right
249. st of operating all the safely oversized motors currently in use Optimally sizing each motor for its application is the sound and most economically profitable policy 114 Consequences of motor over sizing When motots are oversized and operate for extended periods at significantly less than full load there are three significant operational penalttes treduced efficiency reduced slip important if the load is a cube law type and reduced power factor Depending on the motor efficiency will typically peak at somewhere between 75 percent load and full load The larger the motor and the higher its peak efficiency the more likely it will have a relatively flat efficiency curve between 50 percent load and full load with a hump at 75 percent load some 0 3 to 1 points higher than Decreased Slip can negate efficiency gains Ail oad Efficiency drops The base motor efficiency is assumed to be 90 precipitously below 50 percent load with the average 100 hp energy efficient 25 motor losing over two points between Increased energy use 50 and 25 percent load and the average 100 hp standard efficiency induction motor dropping some 5 5 points over the same range Smaller motors lose even more particularly at lower efficiencies A general rule of thumb is that a one percentage point increase in efficiency is equivalent to about a 1 3 point increase in slip a decrease in slip can therefore 1 2 3 4 5 6 7 quickly negate even a signif
250. stem use softened water The ECBC requires condenser water treatment to eliminate mineral buildup ECBC Section 5 2 6 2 Mineral deposits create poor heat transfer situations reducing the efficiency of the unit 5 3 PRESCRIPTIVE REQUIREMENTS ECBC prescriptive requirements apply only if the HVAC system in the building meets the following criteria The system serves a single zone e If the system provides cooling it is through a unitary packaged or split system air conditioner or heat pump e If the system provides heating it is through a unitary packaged or split system heat pump fuel fired furnace electric resistance heater or baseboards connected to a boiler e The outside air quality is less than 1 400 1 s 3 000 cfm and less than 70 of supply air at design conditions If the system meets all of the above conditions then the system must comply with prescriptive requirements for economizers and variable flow hydronic systems sections 5 3 1 and 5 3 2 If not then the users can get useful guidance from ASHRAE 90 1 2004 Section 6 5 FAQs 12 Prescriptive Requirements What is a zone for a HVAC system A space or group of spaces within a building with heating and cooling requirements that are sufficiently similar so that desired conditions e g temperature can be maintained throughout using a single sensor e g thermostat or temperature sensor What is a Heat Pump A heat pump consists of one or more factory made
251. system must be properly installed with the correct amount of airflow and refrigerant charge The system must be appropriately sized according to industry standards There must be easy access to the coil for maintenance What are other important criteria that will aid in my selection decision Effectiveness Durability Lifetime years Space requirements Noise Water consumption Control capacity Thermal comfort Multi zone capacity Natural ventilation Indoor air quality Does it cost morte to install higher efficiency equipment The initial capital cost is often higher but there are other costs to consider in addition to first cost Maintenance costs energy operating cost and lifecycle cost will all be lower with more efficient equipment Is a bigger HVAC system better at handling peak loads Proper sizing of the system is critical to both energy efficiency and cost effectiveness Over sizing the system is unnecessary The compressors in oversized packaged air conditioners or heat pumps cycle frequently and overall efficiency drops with each cycle Frequent cycling also reduces the efficiency of boilers furnaces and many other types of equipment Do daylighting features impact HVAC equipment sizing Yes Daylighting contributes less heat than electrical lighting With properly designed daylighting air conditioning equipment can be downsized saving money on equipment costs and lower energy usage 5 2 1 Natural Ventilation For ve
252. t of the whole HVAC system In a chilled water system for example although the chiller is at the core of the system and typically is the single largest energy user simply selecting a high efficiency chiller does not guarantee high performance Auxiliary equipment such as fans and blowers and design decisions such as approach temperatures can have substantial effects on overall efficiency Thus attention to overall system design and auxiliary components is critical to achieving optimal performance and comfort Even in packaged air conditioning systems leaky ductwork improper sizing refrigerant charge and air flow rates can considerably affect energy performance ECBC 3 2 2 includes Unitary Air Conditioner shall meet IS 1391 Part 1 Table 18 Split air conditioner shall meet IS 1391 Part 2 Tabie 19 Packaged air conditioner shall meet IS 8148 Table 19 and Boilers shall meet IS 13980 the standard specifies the procedure of Boiler to get required energy efficiency that can be equivalent to thermal efficiency mentioned in ECBC with above 75 thermal efficiency Table 18 Power Consumption Ratings for Unitary Air Conditioners Specification Rated Cooling Capacity kcal h Maximum Power Consumption kW 5 2 2 2 3 4 25 9 000 Oo R Source Code No IS 1391 Part 1 1992 Table 19 Power Consumption Rating for Split Air Conditioner Rated Cooling Capacity kcal h Maximum Power Consumption kW 3 000 4 500 6 000
253. te zones The ECBC specifies reasonable design practices and technologies that minimize energy consumption without sacrificing the comfort of productivity of the occupants This guide is designed to help owners designers engineers builders inspectors examiners and energy consultants comply with and enforce India s energy efficiency standards for commercial buildings as described in the ECBC The guide follows the nomenclature of the ECBC is written as both a reference and an instructional guide and can be helpful for anyone who is directly or indirectly involved in the design and construction of commercial buildings TIP Using the Guide It is best to first review Chapters 1 through 3 to understand basic ECBC requirements and their application to all buildings and building systems The subsequent chapters discuss specific systems Envelope Heating Ventilation and Air Conditioning HVAC Service Hot Water Systems Lighting and Electrical Power and can be referenced individually or reviewed together for a complete understanding of the code Each chapter has three parts A brief overview of the respective system covered in the chapter The ECBC criteria for the system including Mandatory provisions Compliance examples Helpful tips Frequently Asked Questions FAQs and Answers Compliance Sheets are incorporated throughout the User Guide and may be copied and used for documenting compliance An expanded list of abbreviations
254. team ECBC requirements can be met by following one of two methods 1 Prescriptive Method which illustrates prescribed minimum energy efficiency for each component of the proposed building 2 Whole Building Performance Method which requires an approved computer software program that models a proposed building determines its allowed energy budget under the ECBC calculates its as designed energy use and determines when it complies with the budget This performance approach is more complicated than the Prescriptive Method but offers considerable design flexibility It allows for code compliance to be achieved by optimizing the energy usage in various design components building envelope HVAC lighting and other building systems in order to find the most cost effective solution In addition all buildings must comply with a set of mandatory provisions as described in Sections 4 2 5 2 6 2 7 2 and 8 2 of the ECBC These mandatory provisions are included and explained in their corresponding sections of this guide ECBC Compliance Mandatory Provisions Prescriptive Requirements including Envelope Trade off Whole Building Performance Method Section 3 outlines compliance options and specifies requirements applicable to all projects The ECBC requires that general and mandatory provisions always be met in every project Technical prescriptive requirements are covered in Section 4 through Section 8 which deal respective
255. terms and definitions can be found in Appendix A 2 SCOPE he ECBC is a code which covers the design and construction of new buildings additions and major renovations to existing buildings building systems and energy using equipment The specific building systems covered are the building envelope heating ventilating amp air conditioning HVAC service hot water and pumping lighting and electrical power Review the following checklist to determine if your building is required to comply with the ECBC The building is 2 1 Either a multi family building with four or more stories a commercial building or a building complex with a connected load of 500 kW or greater or a contract demand of 600 kVA or greater A new building or building complex with conditioned floor area of at least 1 000 m2 A extension of an existing building where the addition plus the existing building exceeds 1 000 m2 of conditioned floor area A renovation or alteration of an existing building where the area of alteration exceeds 1 000 m conditioned floor area APPLICABLE BUILDING SYSTEMS The provisions of this code apply to 2 2 2 3 Building envelopes except for unconditioned storage spaces or warehouses Mechanical systems and equipment including heating ventilating and air conditioning Service hot water heating Interior and exterior lighting Electrical power and motors EXEMPTIONS The ECBC DOES NOT apply to building envelopes
256. the applicable requirements of Sections 4 8 With this approach each component that is being replaced must separately comply with the Code There can be no trade offs among components e The second approach is to evaluate the whole building and show that the annual energy consumption with the proposed alteration does not exceed the annual energy consumption of a substantially identical alteration that exactly meets all the prescriptive requirements This approach permits trade offs between components and equipment as long as the proposed alteration performs as well as if it complied exactly with the prescriptive requirements The proposed alteration must still comply with the Mandatory Provisions This approach only applies to alterations that replace or modify more than one system For instance this approach cannot be applied when just a water heater is being replaced When this approach is used the calculations and performance analysis must be verified by an architect or engineer licensed to practice in the jurisdiction 3 1 4 1 Building Envelope Alterations to the building envelope shall comply with the requirements of JError Reference source not found for fenestration insulation and air leakage applicable to the portions of the buildings and its systems being altered Exception to 9 3 1 4 1 The following alterations need not comply with these requirements provided such alterations do not increase the energy usage of the building
257. the most significant element of the envelope design is the fenestration The fenestration design has a considerable impact on solar gains heat loss and infiltration and in combination with interior space planning determines the potential for daylighting Finding the right fenestration design and optimizing levels of insulation for each climate and internal load condition is a complicated process ECBC requirements help by setting minimum levels of thermal performance for all components of the building envelope and limits on solar gain through fenestration based on climate zone type of space and occupancy Heat Flow in Buildings The flow of heat through a building envelope varies according to the time of the day season and path of the heat For example in summer there is heat influx into the building whereas in winter the built mass loses heat to the outdoor surroundings The heat transfer may take place through the opaque building s envelope or by way of the outdoor air entering the interior infiltration Buildings experience heat loss to and gain from the environment in three principal ways In conduction heat is transferred directly from the molecules of the warmer building surfaces to the molecules of the cooler solids such as earth in contact with the building In convection molecules from the cooler air absorb heat from a warmer surface expand in volume rise and carry it away In radiation heat flows in electromagnetic waves f
258. ting requirements in the ECBC apply to e Interior spaces of buildings e Exterior building features including facades illuminated roofs rchitectural features entrances exits loading docks and illuminated canopies e Exterior building grounds lighting that is provided through the buildings electrical service The following areas DO NOT need to comply e Emergency lighting that is automatically off during normal building operation and 1s powered by battery generator or other alternate power source e Lighting in dwelling units 90 General Design Considerations Using energy efficient lighting equipment is a critical part of designing a lighting system that uses less energy while maintaining or even improving lighting conditions Lighting is one of the fastest developing energy efficient technologies Energy efficient alternatives available in the market include T8 and T5 linear fluorescent lamps mercury vapor lamps sodium lamps Light Emitting Diodes LED s etc For instance modern fluorescent lighting such as T 8 s or T 5 s consume as little as two thirds the energy of antiquated fluorescent lighting Similarly compact fluorescent sources are three to four times more efficient than the incandescent lamps they are designed to replace FAQs 15 Lighting How is Lighting Efficiency Efficacy measured The most common of lighting efficiency or Efficacy is the the lumens produced by a lamp ballast system divided by
259. tion ho R Wind for winter Any 34 0 0 030 6 7 m s 24 km h Wind for summer Any 22 7 0 044 3 4 m s 12 km h Source ASHRAE Fundamentals 2005 CLIV Equation 1 2 is solved for every external constituent element of the building i e each wall window door roof and the floor and the results are summed up The heat flow rate through the building envelope by conduction is the sum of the area and the U value products of all the elements of the building multiplied by the temperature difference It is expressed as Boy Be Ae UAT O 1 5 Where i building element N number of components NOTE e The ECBC prescriptive requirements mandate minimum R values and U values for the different climate zones in India These can be found in Table 4 1 Roof assembly Table 4 2 Walls and Table 4 3 fenestration of the ECBC e The steady state thermal conductivity k value and thermal resistances R values of building components walls floors windows roof systems etc can be calculated from the thermal properties of the materials in the component Tables 1 4 in Chapter 25 of the ASHRAE Fundamentals and the Appendix C of the ECBC list thermal resistances of building walls floors and ceilings EXAMPLE 1 0 Suppose we have a room that is 5 m long 4 m wide and 3 m high The external walls of the room are made up of 200 mm thick insulated concrete block wall The roof of the room is made up of a RCC
260. ucing energy costs improving occupant comfort cutting maintenance costs increasing the life cycle of the roof and contributing to the reduction of urban heat islands and associated smog Reflectance albedo is measured on a scale of O to 1 with 0 being for a perfect absorber and 1 being a perfect reflector An ideal exterior surface Thermal mmitear Coating for a hot climate would have _ lage ee a reflectance of near 1 0 absorptance hits the roa radiate abporbeat Of near 0 and infrared emissivity near 1 0 to radiate absorbed heat back to d P the sky What is meant by Urban Heat Island effect An Urban Heat Island is a Some heat is absorbed by the mof and metropolitan urban area which is transferred te the building below significantly warmer than its surroundings As population centers grow in size they tend to have a corresponding increase in average temperature Scientists refer to this phenomenon as the Urban Heat Island Effect UHIE The two main causes of the CA urban heat island is modification of the land surface by urban development and waste heat generated by energy usage One consequence of urban heat islands is the increased energy required for air conditioning and refrigeration in cities that are in comparatively hot climates What types of roofing products are available for commercial and residential applications Products for low slope roofs found on commercial and industrial buildings fall
261. uded polystyrene foam XPS Expanded polystyrene Foam EPS or Bead board Polyurethane foam Polyisocyanurate foam Reflective Systems Foil faced paper Foil faced polyethylene bubbles Foil faced plastic film Foil faced cardboard Fitted between studs joists and beams anaes must be protected by an air barrier membrane in order to maintain the installed R value conductive loops amp wind washing The air barrier can be installed over exterior and or interior sheathing and must be continuous Blown into place or spray applied by special equipment Insulation must be protected by an air barrier membrane in order to maintain the installed R value conductive loops amp wind washing The air barrier can be installed over exterior and or interior sheathing and must be continuous Interior applications Must be covered with 12 inch gypsum board or other building code approved material for fire safety Exterior applications Must be covered with weather proof facing or continuous Air and Weather Resistive Barrier WRB Foils films or papers Fitted between wood frame studs joists and beams Unfinished walls floors and ceilings Enclosed existing wall cavities or open new wall cavities Unfinished attic floors and hard to reach places Basement walls Exterior walls under finishing Some foam boards include a foil facing which will act as a vapor retarder Additionally some insulation mater
262. uilding Roof Area 1 863 sq m Roof Insulation Rigid Board 1 inch R 2 1 m2 C W Wall Area 3 706 sq m Wall Insulation Rigid Board 1 inch R 1 41 m C W Fenestration Area 487 sq m Window to Wall ratio 487 3706 13 Fenestration SHCG 0 20 U factor 3 30 Skylight Area 112 sq m Skylight to Roof Area 112 1863 6 Does my building envelope comply Prescriptively with the ECBC No this building does not comply because the prescriptive approach limits skylights area to a maximum of 5 of the roof area This building would need to comply under the envelope trade off option of the Whole Building Approach As with windows the skylight roof ratio must be calculated separately for each space category The criteria for each space category are determined from its own skylight roof ratio not the skylight roof ratio for the whole building FAQs 5 Glazing What is the most important feature that a building professional should look for regarding windows doors and skylights The SHGC and U factor ratings are the most important items to verify during inspections Building professionals should verify that the ratings of the installed windows doors and skylights meet or exceed the ratings specified on the plans It is also important to verify that the same window area has been installed as the area shown on the plans and that the glass orientation on the plans and building are consistent What is the Solar Heat Gain Coefficient
263. urce Report on alternative building technologies Centre for Sustainable Technologies and Department of Civil Engineering Indian Institute of Science Bangalore 2003 CLVIII EXAMPLE 2 Suppose we have a residential room that is 5 m long 4 m wide and 3 m high The room is maintained at 23 3 Deg C by an air conditioner with a ventilation rate of 2 air changes per hour Calculate the convective load due to ventilation Outdoor temperature is Daily average outside temperature is 32 7 C Density of air 0 1 2 kg m3 and Specific heat of air C 1005 J kg K SOLUTION 2 Using Equation 1 9 Convection load Qa CAT RE Where i ee Given N 2 V 5 x 4 x 3 60 Cu Mt V 5 4 3 2 3600 0 03 AT 32 7 23 3 Deg C 305 7 296 3 K 9 4 OQ L2rtSedtede 2 3600 1005 94 12 1 4 Heat Transfer Through Radiation Radiation is the heat transfer from a body by virtue of its temperature it increases as temperature of the body increases It does not require any material medium for propagation When two or more bodies at different temperatures exchange heat by radiation heat will be emitted absorbed and reflected by each body The radiation exchange between two large parallel plane surfaces of equal area A at uniform temperatures T and T2 respectively can be written as a m ey ett ty ee 1 12 with il Sore they tlhe AY eee eee te ete 1 13 Where Qi2 net radiative exchange between sur
264. use of time clocks temperature controls thermostats and two speed or variables speed drives for fans 5 2 3 1 All mechanical cooling and heating systems shall be controlled by a time clock XXX 64 5 2 3 2 xxx 5 2 3 3 The other mandatory control requirement is for cooling towers and closed circuit fluid coolers These must have one of the following to control the fans two speed motors pony motors or variable speed motors ECBC 5 2 3 3 Exceptions All mechanical cooling systems which are at least 24 kW 8 tons and heating systems which are at least 7 kW 2 tons are required to be controlled by a time clock ECBC 5 2 3 1 It is further specified that time clocks used have the ability to do the following e Control system start stop for 3 different day types e Retain programming for at least 10 hours during a power loss and e Have a manual override that allows temporary operation for 2 hours Example 6 Thermostat Compliance Q Can a thermostat with set points determined by sensors such as a bi metal sensor encased in a bulb be used to accomplish a night setback A Yes The thermostat must have two heating sensors one each for the occupied and unoccupied temperatures The controls should allow the setback sensor to override the system shutdown If heating and cooling are being supplied by the same unit they must be interlocked to prevent simultaneous heating and cooling 65 Energy and Water Efficiency in
265. ution systems in buildings from power factor losses to thermal monitoring of junction boxes and main power distribution boards 8 2 MANDATORY REQUIREMENTS The mandatory requirements of the ECBC cover the following elements of a building s electrical system e Transformers e Motors e Power factor correction e Check metering and monitoring e Power distribution 8 2 1 Transformers Transformers are used within commercial buildings to supply electrical power to individual circuits for lighting plug loads air conditioning and other applications Transformers reduce the higher voltages used by electric utilities for power distribution to lower levels required by building equipment They are generally located out of sight in mechanical spaces and other out of the way locations and are therefore forgotten about when considering energy efficiency Transformers last a long time on the order of 35 years thus opportunities for energy saving upgrades are best captured for newly installed transformers or when replacement is due Electrical power distribution transformers are used in virtually every commercial building They are energized around the clock providing power to the building s electrical equipment and consuming energy whether or not this equipment is operating Because distribution transformers consume energy even when the building is not occupied or equipment is not operating more efficient distribution transformers
266. vertical transportation areas The north south and west facades of the building are the external walls with windows All windows have single pane reflective glass The frame for all these windows is an unlabelled thermally unbroken aluminum frame All the windows have fixed glazing The east side of the building is in common with the other building block Figure 30 First Floor Plan of the Case Study Building R F The proposed building will have approximately 80 conditioned area with some proposed unconditioned areas like the staircases All the external walls are brick construction with stone cladding on the exposed facade Internal partition walls are designed as brick construction with plaster on both sides Over deck insulation for the roof will be used to reduce the heat gain through the exposed roof surface A high efficiency electric lighting system will be used throughout the building Lighting power density on an average is 8 61 W m in the office areas and 1 61 W m in the stilt level parking CXVIII Water cooled centrifugal chillers are used for the cooling requirements of the building All the spaces in the building are served by multi zone variable air volume VAV air handlers which are connected to a central chiller The stilt level parking is semi exposed area and is naturally ventilated Efficient chillers of 570 ton each and with a COP of 6 1 are proposed for
267. where the warmest air of the building tends to collect Portions of roof that serve as curbs that mount the skylight above the level of the roof See Error Reference source not found 4 below are part of the opaque building envelope The SHGC criteria for skylights depends on the percentage of skylight glazing and the U factor criteria depends on whether or not the skylight is intended to be mounted on a curb Skylights need to comply with the maximum U factor and maximum SHGC requirements of ECBC Table 4 6 reproduced below in Table 15 Also skylight area is limited to a maximum of 5 of the gross roof area under the prescriptive approach requirements Buildings that have a skylight roof ratio greater than 5 must use the Building Envelope Trade off Option or the Whole Building Performance Method Figure 13 Skylight Installations 51 Table 15 Skylight U Factor and SHGC Requirements Maximum U factor Maximum SHGC Climate With Curb w o Curb 0 2 SRR 2 1 5 SRR Composite 11 24 7 71 0 40 Hot and Dry 11 24 7 71 0 40 Warm and Humid 11 24 7 71 0 40 Moderate 11 24 7 71 0 61 Cold 11 24 7 71 0 61 SRR Skylight roof ratio which is the ratio of the total skylight area of the roof measured to the outside of the frame to the gross exterior roof See Section 11 2 2 for typical complying skylight constructions Example 5 Prescriptive Requirements for Skylights Location Chennai Climate Zone Warm Humid Building Type Daytime Use B
268. ws businesses to analyze and track changes in energy demand and therefore to manage their energy consumption more effectively Energy metering is not a new concept and has been used by large energy intensive businesses for many years to monitor and reduce waste The ECBC requires that buildings have energy consumption metered to allow buildings to be easily monitored The ECBC requires check metering based on three scenarios e Services gt 1 000 kVA must have permanently installed electrical metering to record e Demand kW e Energy kWh e Total Power Factor kVARh e Current Voltage and total harmonic distortion THD 2 Services lt 1 000kVA but gt 65 kVA must have permanent metering to record e Demand KW e Energy kWh e Total Power Factor kVARh 113 3 Services lt 65 kVA must have permanent electrical metering to record energy kWh The widespread over sizing of induction motors Motor over sizing is a subtle problem in industrial and commercial systems because unlike most other application problems it rarely manifests itself in the failure of a motor and the process shutdowns that follow Rather this problem is more like a low level infection that saps energy and efficiency while padding utility bills for year after year It takes concerted effort to evaluate motor loading particularly in facilities where motors are widely distributed In facilities where maintenance staff keep busy fixing breakdowns assessment
269. xcellent strength and durability qualities Stone Although the density of stone is very high sandstone has a low R value due to its high conductivity This can be improved by increasing the thickness of material in the walls Concrete Made from cement and additional materials such as fly ash slag cement aggregate and chemical admixtures concrete is poured or used in blocks Plastering Material Additional thermal value is added to the wall through plastering materials used to provide a smooth interior surface Source Dr Ing Jyotirmay Mathur Malaviya National Institute of Technology 38 Table 7 Thermal Properties of Commonly Used Construction Materials in India e Thermal Properties Resistance R Density k Per inch Cp P kg m Wim ae UI ake K 2400 1 21 1 47 0 83 0 68 a 2240 1 07 1 30 0 94 0 77 o Brick Conductivity Specific Heat Basic Material Type Burnt Cla i 1920 0 81 0 98 1 24 1 02 1600 0 61 0 74 1 65 1 36 ia 2880 10 4 0 10 Stone Sand Stone 2240 3 5 0 29 0 73 1920 1 9 0 53 no pe Hollow Blocks 1040 Lime Stone 1920 Concrete 1600 Concrete 1920 Maan fioo and Mortar FoU 1280 1920 1600 1280 Sand Aggregate 75 5 0 013 10 mm Cement Plaster 0 84 Sand Aggregate 37 8 0 026 20 mm Gypsum Light weight Plaster 13mm 17 7 0 056 Sand Perlite Aggregate 63 0 016 13 mm Source ASHRAE Hand Book 1997 Chapter 24 Concrete Foam Concrete
270. ximum lighting power requirements for exit signs and requires that all internally illuminated exit signs 97 not exceed 5 W per face Most LED and some CFL exit signs meet this recommendation Due to their low power draw LED exit signs can be purchased with built in back up power supplies i e batteries With an estimated service life of 10 years or more LEDs require significantly fewer lamp replacements than exit signs equipped with either incandescent lamps or CFLs 7 2 3 Exterior Building Grounds Lighting If luminaires used to light exterior building grounds operate with greater than 100W they are required to have a minimum efficacy of 2 60 Lumens Watt An exception is allowed for luminaires that are either controlled with a motion sensor or are used for emergency lighting As shown below in Figure 23 luminaires meeting these requirements include fluorescent mercury vapor and high pressure sodium Figure 23 Watts per Lighting System Efficiency i j J 7 3 PRESCRIPTIVE REQUIREMENTS The prescriptive section of the lighting system requirements regulates both interior and exterior lighting power The first may be determined by either of two different methods the building area method or the space function method One method must be selected and trading between methodes are not accepted Specific power limits are listed for exterior spaces 7 3 1 Interior Lighting Power Interior lighting includes all permanently insta
271. y Commission s Appliance Database under Certified Water Heaters Instantaneous Gas A gas water heater controlled manually or automatically by water flow activated control or a combination of water flow and thermostatic controls with a manufacturer s specified storage capacity of less than two gallons Instantaneous Electric An electric water heater controlled automatically by a thermostat with a manufacturer s specified storage capacity of less than two gallons Note Instantaneous water heaters are not generally designed for use with solar water heating systems or as heat sources for indirect fired water heaters They are also typically inappropriate for use with recirculation systems Consult manufacturer s literature when considering these applications Indirect Gas A water heater consisting of a storage tank with no heating elements or combustion devices connected via piping and recirculating pump to a heat source consisting of a gas ot oil fired boiler or instantaneous gas water heater see note following the definitions of Instantaneous Gas and Electric Passive Solar Systems which collect and store solar thermal energy for domestic water heating applications and do not require electricity to recirculate water through a solar collector Active Solar Systems which collect and store solar thermal energy for domestic water heating applications requiring electricity to operate pumps or other components Wood Stove Boilers Woo

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