DESIGN AND ENGINEERING GUIDE high and low
Contents
1. Height S S x ea Total Be T 4 i Spread n Oe Ve A CLLLLLELELLLLELELLLLELELLLL ELE TEESE DG Total Spread Height 5ft x 2 0 mounting angle Total Spread Height 5ft x 4 45 mounting angle Heat distribution is dependent on the type of tube system used straight versus U tube and the length Heat intensity along the length of the tube system varies considerably A solid understanding of this distribution is key to ensuring that the equipment is properly specified for the application Misunderstanding is the number one cause of complaints of insufficient heat The first step toward understanding the distribution of radiant heat is gaining an appreciation for the significant effect that temperature has on radiant intensity The basic equation for calculating radiant intensity is R Watts in x o x ATemp where e Emissivity of the emitter tube system o Stefan Boltzmann Constant ATemp Temperature difference between the emitter tube system and the absorber people Without going into the theory behind the calculations the important item to note is that the radiant intensity varies by the absolute temperature difference raised to the 4 power multiplied by itself 4 times which tells us that temperature has a significant effect on radiant intensity Since the tube system is a long heat exchanger it is losing heat along its Understanding Heat Spread and Throw Di2. yo MODINE Introduction Modine gas fired infrared heaters for comfort heating applications can be used alone or in combination with other Modine heating equipment such as gas fired unit heaters make up air units etc to provide superior comfort heating solutions This guide will provide a basic understanding of the principles of using infrared heat TABLE OF CONTENTS Introduction Typical Applications Why Use Infrared SI Metric Conversion Factors Types of Heat Transfer Types of Infrared Heaters Understanding Heat Spread Distribution Infrared Heater Selection Procedure and Data Clearance to Combustibles Application Spot Heating Application Partial Building Area Heating Application Total Building Heating Additional Considerations Mounting Height Building Obstructions Low Intensity Tube Length Considerations Availability of Utilities Gas and Electric Venting Ventilation Multiple Low Voltage Heaters Single Stat Humidistat Thermostat Location Contaminated Atmospheres Negative Pressure in Space Outdoor Applications Duration of Operation Low Intensity Tube System Expansion Accessories Typical Selection Considerations Summary Performance Data Total Building Heating Only A WARNING Improper installation adjustment alteration service or maintenance can cause property damage injury or death and could cause exposure to substances which have been determined by various state agencies to cau
3. located over the entire packaging line remember from the heat spread distribution discussion that when the tube temperature falls below approximately 600 F radiant heat will be negligible The first two people on the line will feel comfortable but the person loading the trailer will feel very little heat One option would be to place high intensity heater s in that area and treat it as a spot heating application within a partial area heating application Example 2 The use of two 30 foot straight tube systems will help significantly over the configuration shown in Example 1 The employees on both ends will be blanketed with radiant heat However remember from the discussion on heat spread distribution that the tube end opposite the burner will be about 350 to 400 F The person in the middle of the line may not receive an ideal level of radiant heat although they may get some heat from adjacent warmer sections This is a good layout but comfort could be enhanced Example 3 The use of two 60 foot U tube systems is the ideal solution for ensuring ideal radiant heat across the entire packaging line Summary Example 1 Bad application occupant complaints on one end of the assembly line Example 2 A good layout although temperature may be a bit low in the middle of the assembly line Example 3 A great layout with even heat distribution across the entire assembly line Choosing between Example 2 and Example 3 as a
4. 100 000 125 000 150 000 175 000 200 000 Minimum Clearance Ho Combustbes __ Combustibles See Pages 4 and 5 Available Certified Tube Lengths feet 20 30 20 30 40 20 40 30 50 40 50 60 50 60 50 60 70 50 60 70 IPT Models The heater placement chart is suggested under normal circumstances Building design and obstructions and application differences may require adjustments E E G E See the figure at the right for graphical depiction of distances indicated i Minimum clearance to combustibles must be maintained at all times Propane operation not available on the following models Between Burners Between Rows IPT75 with 40 foot tube system length e IPT100 with 50 foot tube system length el Unit to Wall A iy RS CG Table 12 2 Suggested Heater Placement for High Intensity Infrared Heaters MHR Model Size MBH 30 60 100 120 160 200 Rea se el Mounting Height by Mounting Angle ft FEA Units 15 30 Between Rows Unit to Wall min 6 10 Between Rows max 60 80 Ht Minimum Clearance to Combustibles See Pages 4 and 5 Unit to Wall The heater placement chart is suggested under normal circumstances Building design and obstructions and application differences may require adjustments See the figure at the right for graphical depiction of distances indicated Minimum clearance to combustibles must be maintained at all times Commercial
5. F c c O NM z Z Z olo w e N Z A O oO O1 O O1 00 O Refer to the figures below Figure 5 1 High Intensity Clearance to Combustibles le U TUBE U TUBE 0 MOUNTING ANGLE 45 MOUNTING ANGLE MAXIMUM Figure 5 4 Low Intensity Clearance to Combustibles U Tube Systems and U Tube CHAIN LOCATION BOTTOM THE GAS MANIFOLD AND CONTROLS MUST BE LOCATED AT THE LOW END OF THE HEATER Minimum Clearance to Combustible Materials Mioma Height Stacking Haight 9 200 5 Infrared Heater Selection Procedure Spot Heating Application Intended Operation of the System Infrared systems can serve three basic applications e Spot heating Used for heating only small areas such as a loading dock or a single person work cell Excellent application for infrared e Partial building heating Used to heat sections of a building such as an assembly line or office section located in an open area of a warehouse Excellent application for infrared e Total building heating Used to heat the entire building This is a fair application for infrared but other equipment should also be considered as an alternate The following section will provide specific background information necessary to satisfy each of these applications Spot Heating Spot heating is used for individual workers who require the replacement of body heat loss where heating
6. Products Group A D Modine Manufacturing Company MODINE 1500 DeKoven Avenue w Racine Wisconsin 53403 2552 Telephone 1 800 828 4328 HEAT Fax 1 800 204 6011 www modine com Modine Manufacturing Company 2015 9 200 5
7. This is often a trade off with optimizing the coverage area which is usually end to front positioning Venting Ventilation High intensity units require a minimum positive air displacement of 4 CFM per 1000 Btu hr input for natural gas or 5 CFM per 1000 Btu hr input for propane gas Please see the Installation and Service Manuals for additional information and requirements For unvented units it is important that the building have adequate insulation especially the ceiling The products of combustion which contain a great deal of moisture will rise in the building When these moist gases come in contact with the cold building surfaces considerable condensation can occur This moisture can cause a great deal of damage and possibly cause safety hazards such as water leaking onto the floor causing slippery conditions For low intensity units limitations on the length of flue pipe allowed for different ratings and tube system lengths exist These limitations can be found in the Installation and Service Manuals Low intensity units can be common vented in pairs out a single larger vent to reduce the number of building penetrations for venting and therefore installed cost Units must be of identical burner input rating and tube system length and must be controlled by a single thermostat Please refer to the heater Installation and Service Manual and the National Fuel Gas Code Handbook for additional information and requirements shorter
8. tube lengths Please see the Performance Data Figure 9 2 Typical Common Venting for additional information e A layout as uniform as possible should be used however some areas may be exceptions such as placing higher ratings or a higher number of units with short tube lengths where heat loss is greater Examples include a Northern facing wall with a prevailing wind or a frequently opened overhead door 9 200 5 To Vent Termination Infrared Heater Selection Procedure Additional Selection Considerations Wiring Multiple Low Voltage Heaters to a Single Thermostat When using a single thermostat to control multiple heaters with low voltage 24V control relays are required per the National Electric Code to isolate the control transformers on individual heaters so that the secondary side or low voltage side of control transformers are not wired in parallel Please see Literature 9 410 latest revision for additional details Humidistat For unvented heater applications there are minimum ventilation requirements These requirements were briefly discussed in the previous section However with ventilation requirements met there still may be excessive humidity in the space A humidistat should be considered to activate additional exhaust fans if humidity rises Thermostat Location It is important to place thermostats out of the line of sight from the heaters If placed in the line of sight with the heaters they will re
9. ad erroneous temperatures not actual air temperature In spot or area heating applications it is common to use On Off switches in lieu of thermostats as the intent is to cause comfort from the radiant infrared not from heated air Contaminated Atmospheres Infrared heaters should never be used in areas where hazardous or explosive materials exist They also should not be used in areas where chlorinated halogenated or acid vapors are present For dirty environments that are not classified as an area requiring explosion proof equipment low intensity units can be used with clean outside combustion air ducted to the units However the unit is not considered to be separated combustion or explosion proof Negative Pressure in Space High intensity units are generally tolerant of negative pressure in the space being heated since the units operate unvented Low intensity units are generally tolerant of slight negative pressure in the space being heated since the units are power exhausted However when the negative pressure may be more significant low intensity units are advantageous as outside combustion air can be ducted directly to the unit so that the intake and exhaust are both at atmospheric pressure Outdoor Applications Modine offers a line of low intensity units that are suitable for outdoor applications It is important to note that perceived performance will not be the same for an outdoor application as for an indoor applica
10. ce to combustibles from the top Based on the required clearance the mounting height should not exceed 17 feet i e ceiling height of 18 feet 12 17 feet This would make the 175 000 Btu hr unit a less likely choice since it is recommended to be mounted above that height Figure 8 1 Mounting Height for Example 1 Determine the Number of Heaters Required With available ratings known the total number of heaters required can be determined by dividing the total building heat loss by the input rating of each heater Multiple ratings may be used based on the building layout and dimensions Refer to the following section titled Heater Placement for information on selection based on layout 8 9 200 5 Heater Placement Placement of the heaters should be concentrated where heat loss is greatest In the case of total building heating the heat loss occurs mainly along the perimeter of the building While it makes sense to place the heaters along the perimeter if the distance between parallel walls exceeds 100 it is best to use a combination approach of perimeter and row heating The heater capacity along the perimeter should be at least 80 of the total system capacity with the remaining maximum 20 of the total system capacity located in parallel rows toward the center of the building The center rows are used to compensate for the roof heat losses Example 2 Expanding on Example 1 the building is 200 long x 160 wi
11. de with a calculated heat loss of 1 600 000 Btu hr Example 1 determined that units rated 125 000 or 150 000 Btu hr should be considered Which will work best If the building heat loss is 1 600 000 Btu hr the number of 125 000 Btu hr units required would be 13 1 600 000 125 000 12 8 13 units For 150 000 Btu hr rated units the quantity required would be 11 units Reviewing the figure for Example 2 on the following page there will be 3 units required to cover each of the 200 long walls using 60 foot straight tube systems Since the distance between parallel walls exceeds 100 it is best to use a combination of perimeter and row heating Adding a third row in the center will require another 3 units So far this is 9 units total and the 160 long ends of the building need to be covered Given the distance the minimum tube length should be 60 with 2 systems required on each end The choices at this point are e Use 13 150 000 Btu hr units with 60 straight tube systems Total input will be 1 950 000 Btu hr e Use 13 125 000 Btu hr units with 60 straight tube systems Total input will be 1 625 000 Btu hr e Use 13 units that are a combination of 125 000 and 150 000 Btu hr units Total input will be based on the mix of the ratings selected All three choices are acceptable The use of 13 125 000 Btu hr units may have trouble maintaining design temperature on the coldest days that fall below the winter design te
12. e pressure conditions Utilizing outside space combustion air also aids in these applications commercial and industrial applications only outdoor applications High Humidity Locations Poor choice High intensity units operate Excellent choice The units are vented outside e g car washes unvented Water vapor is a by product of the to avoid adding humidity to the space Dry combustion process which would add to the high outside air can be ducted to the unit for humidity already present in these locations combustion A unit suitable for outdoor applications may be recommended Dirt Floors e g stables Fair to Poor choice The ground acts as a huge heat sink conducting heat away from the surface arenas etc The ground will absorb the infrared but will not radiate the energy back Environments with Poor choice Gas fired units should never be used in areas where chlorinated halogenated or acid Chlorinated Halogenated vapors exist or Acid Vapors Present Hazardous Areas with DANGER Units must NOT be installed where they may be exposed to a potentially explosive or Potentially Explosive or flammable atmosphere Flammable Materials 9 200 5 11 Performance Data Total Building Heating The data on this page applies only to Total Building Heating applications as discussed on page 8 Table 12 1 Suggested Heater Placement for Low Intensity Infrared Heaters ft Input Rating Btw hr 50 000 60 000 75 000
13. e shows a typical 60 foot U tube system temperature profile 30 feet out to a 180 U tube and 30 feet back The temperatures are adequate for comfort radiant heating over the entire 30 foot length since the temperatures are above 600 F Like the straight tube system radiant heating will be negligible over the last 20 feet of the tube system however since that portion is running next to the first 20 feet of the tube system where temperatures are the highest there is no adverse effect on radiant heating output Figure 4 2 60 Ft U Tube Temperature Distribution Approximate Tube Temp Across Tube System 60 Foot U Tube 1000 900 800 700 600 0 5 10 15 20 25 30 35 Feet from Burner Temperatures shown are for example purposes only Actual results may vary based on input rating gas heat value altitude etc 4 9 200 5 Understanding these temperature distributions and resulting effects on comfort heating will be important as application specific examples are covered in later sections of this guide It is important to note that the recommended mounting heights shown in the Performance Data are based on those units providing comfort heating levels when mounted within the ranges shown From the previous discussion it can be seen that the heat spread and throw will increase as the mounting height is increased As the height specified changes it is important to select the unit ratings t
14. ection occurs a solid understanding of the infrared heater heat spread distribution is required to avoid potential misapplications of the equipment This section provides the basic information to gain this understanding High Intensity Heat Spread Throw Heat spread width as shown in Figure 3 1 is dependant on the mounting height and relatively unaffected by the mounting angle The spread at floor level is approximately twice the mounting height However someone occupying the edge of that space will feel minimal heat To cover an entire area up to 5 feet high shoulder level for the average worker the mounting height should be approximately 5 feet above half the distance of the desired width For example if the shoulder height area width is to be 40 feet wide the mounting height should be approximately 25 feet above the floor 5 feet x 40 feet 25 feet The actual floor level spread will be approximately 50 feet but the radiated infrared heat is negligible at the edge of that area Figure 3 1 High Intensity Heat Spread Width A 7 N 7 N 7 N 7 N 7 N N N Height N N N N Spread Width ES VLLLELLLLELLLLELLLLELLELELLLLELLEL Spread Width Height 5ft x 2 Heat distribution throw is dependent on both the mounting height and the mounting angle Ata 10 mounting angle the heat throw at a height of 5 feet will be approximately 1 2 x the mounting height 5 feet in one directi
15. ects in the space such as storage racks machines the floor and people These objects in turn radiate the heat gained from the infrared heater Conduction This is the transmission of heat through solid objects by the exchange of energy from warmer molecules to cooler molecules An example is a pot on a stove Even though the flame does not directly heat the handle it gets hot because heat from the bottom of the pot is transferred to the cooler handle In the case of the infrared heating application the objects in the space conduct heat gained through radiation from the infrared heaters For example the warmed floor conducts heat through the shoes of a person standing on the floor warming the person s feet Convection This is the transmission of heat through gases or liquids by the movement of masses of the gases or liquids An example is air moving across a fin tube heater As the fin tube element heats the surrounding air the air becomes less dense and rises Cooler air takes its place surrounding the heating element and is heated This process continues heating the air in the room In the case of the infrared heating application the warmed objects such as the floor and storage racks heat the air surrounding the objects 2 9 200 5 Types of Infrared Heaters Modine offers two types of infrared heaters high intensity and low intensity Both are certified for commercial and industrial applications only The followi
16. es not apply to just wood drywall etc but some other commonly encountered items as well Below are some examples e Vehicles parked below the heater e Sprinkler heads near the unit e Storage of combustible materials This is sometimes overlooked and requires additional action on the part of the building owner operator In these locations signs shall be clearly posted in the vicinity of the heater where readily apparent to material handlers to indicate the maximum permissible stacking height to maintain required clearances from the heater See Figure 5 2 on the following page for additional details Infrared Heater Selection Procedure General Table 5 1 High Intensity Minimum Clearances to Table 5 2 Low Intensity Clearance to Combustibles Model Model Size C Series MBH o9 5 Combustibles inches 50 60 IPT 75100125 9 76 24 150 175 200 Clearance to each end and above the U Tube is 12 inches Refer to the figures below Model Sizes 30 60 90 100 160 200 oO O oO O iN O SIDE OF HEATER BACK OF HEATER TOP OF HEATER Mounted 0 29 Mounted 30 only w Optional Heat Deflector 0 29 w Optional Heat Deflector 30 BELOW HEATER Standard Reflector w Optional Parabolic Reflector OO oO Figure 5 3 Low Intensity Clearance to Combustibles Straight Tube Systems CHAIN LOCATION W gt gt w D K BR S w wla o
17. foot long tube systems in a U tube configuration Mounting angle should be 45 ideally with two units one on each side of the person Infrared Heater Selection Procedure Partial Building Area Heating Partial Building Heating Partial building or area heating is used for smaller areas within a building that are larger than a spot heating application Examples include an assembly line or an open office service counter area in the middle of a large open warehouse type building These areas all have people moving about in a small area that need to be kept warm without heating the remainder of the building to comfort heating levels Typically low intensity units are the ideal choice for partial area heating Critical to a proper selection layout is having a clear understanding of the heat spread distribution across the length of the tube system This was discussed in an earlier section but to better illustrate the differences that tube lengths and configurations make in an application we will look at an imaginary fish packing company that has a 60 foot long fish packaging line At one end an employee is loading frozen fish onto a conveyor In the middle an employee is packaging the frozen fish for shipment At the far end an employee is taking the boxes and loading in a refrigerated trailer on the dock Example 1 A common mistake is to layout the heating system as a single 60 foot straight tube system While it will be physically be
18. ger volumes of cold air before occupants feel warm However an infrared heater supplies immediate heat to the workers and objects in the space The ability to control heating in zones is very easy with infrared heaters because infrared is well suited for heating small areas This would be difficult and inefficient with forced air heaters SI Conversion To To To Multipl To gallons 379 1 Heat Transfer and Infrared Heater Basics Types of Heat Transfer Infrared heaters primarily transfer heat directly through radiation However infrared heaters indirectly cause conduction and convection heat transfer within a heating application The following is a summary of the different types of heat transfer Radiation This is the transmission of heat through a space by infrared energy rays emitted from a hot surface The infrared energy is transmitted through space and heats only the objects the energy strikes The energy can actually pass through a vacuum and remain virtually unchanged A familiar example is the Sun which radiates energy to objects such as the Earth When a person is outside on a sunny day the person feels the warmth of the Sun If a cloud passes over the person feels cooler Although the air temperature doesn t change the amount of radiant energy reaching that person is reduced since the water droplets of the cloud absorbed some energy In the case of infrared heaters the heat is radiated from the heater to obj
19. hat reflect that height Mounting a unit higher than recommended can result in complaints of low heat output Mounting a unit too low can result in complaints of too much heat While the coverage has changed the infrared output has remained constant resulting in an increase or decrease in the intensity of the infrared energy over the given area It is also important to understand that high intensity units generally have to be mounted higher than low intensity units The following table summarizes this typical data Table 4 1 Typical Mounting Heights ft for Comfort Heating MBH High intensity MBH High Intensity Po 8010 13 Low Intensity 10 12 12 14 15 22 120t0 150 16 25 160 17 29 N A o 175 18 28 20 30 175 o 200 _ 19 31 Infrared Heater Selection Procedure The proper selection of heaters in the design and layout of an infrared heating system is determined by a number of factors but primarily by the following Clearance to Combustibles Clearance to combustibles is also a critical in selection of the unit Please refer the unit Installation and Service Manual for complete details Care must be taken to ensure that the units have adequate clearance around them so that combustible materials will not ignite or be damaged As a guideline certified minimum distance to combustible material is based on the combustible material surface not exceeding 90 F above ambient 160 F typical This do
20. he occupant of the space should make the determination of the ambient conditions based on personal perception Once ambient conditions are determined heater ratings can be determined based on the available mounting height For areas requiring larger coverage units with higher ratings can be used provided the available mounting heights are adequate Note that the table assumes a 30 mounting angle Mounting angles less than 30 are not advisable since the heater would then need to be mounted more directly overhead of the person In this situation excessive infrared energy would be directed at the head of the person causing discomfort and uneven heating over the surface of his her body 6 9 200 5 Table 6 1 Spot Heater Selection Table A Conditions Mounting Height Recommended Horizontal Distance to Person Approximate Area of C MHR 30 10 5 6 6 T 9 6 7 7 MHR 6 8 MHR100 10 11 11 12 11 12 MHR120 12 13 13 14 12 14 oa 14 16 16 20 Note that these are recommended values only and may need to be adjusted to meet requirements of the actual installation A 30 mounting angle is required Figure 6 1 Typical Spot Heater Mounting Single Heater Shown Horizontal Distance to Person Mounting Height Low Intensity Unit for Spot Heating While high intensity units are the best option for spot heating applications low intensity units can be used but should be kept to 20 or 30
21. ing Excellent choice Good choice when U tube systems are used Partial Building Heating Good choice Excellent choice when U tube systems are used Total Building Heating Fair choice for high mounting heights or if Fair choice when used with straight tube obstructions exist that would interfere with low systems intensity tube heater installations Inexpensive Installation Excellent choice All gas power and control Good choice All gas power and control connections are made in the same vicinity Units connections are made in the same vicinity of with millivolt controls do not use external electric each other Common venting reduces power further minimizing installation costs installation costs from reduced roof or sidewall Units are unvented eliminating building roof or penetrations sidewall vent pipe penetrations Venting Options None Units operate unvented Units can be common vented in pairs to enable the use of one vent pipe which minimizes installation costs as there is only one roof or sidewall penetration See Common Venting of Low Intensity Infrared Heaters for requirements costs since there are no moving parts to service Power exhauster requires minimal maintenance Combustible Materials require lower clearances Dirty Environments Fair choice Foreign particles and dirt could be Good choice when outside combustion air is introduced to the heater requiring more frequent ducted to the unit While not considered main
22. ith infrared are best accomplished using low intensity tube heaters However Modine offers a number of different heating equipment options for building heating so all options should be considered This guide will only focus on an infrared heater layout The selection process for infrared in a total building heating application is more of an art than a science One must not only know the heat loss of the building and the dimensions but other characteristics such as the available mounting height clearance to combustibles and building layout which includes the shape of the area location of utilities physical interference from equipment such as lights or overhead cranes etc The selection layout process is outlined below Determine Available Ratings After the type of infrared heater to be used has been determined high intensity low intensity or a combination of both available ratings are determined based on the mounting height and required clearances to combustibles as indicated in the Performance Data tables on page 12 Example 1 A building has a ceiling height of 18 feet Low intensity units are to be used What are the available unit sizes that should be considered in the layout From the Performance Data the applicable unit ratings are 125 000 Btu hr for mounting between 15 to 22 feet 150 000 Btu hr for mounting between 15 to 25 feet and 175 000 Btu hr for mounting between 18 to 28 feet Each requires a minimum of 12 clearan
23. mperature The 150 000 Btu hr units will normally accommodate even the coldest days but may be oversized for normal conditions operating on zone thermostats may minimize cycling Note that the layout solutions above meet the recommended 80 20 rule for capacity location in a combination perimeter and row layout With 10 of the 13 units located along the perimeter assuming all units are of the same rating 77 of the layout capacity is on the perimeter with 23 of the capacity in the center row It is also important to note that these three solutions are by no means the correct answers as there could be considerably more correct answers There are some other factors that should considered that may affect the design of the layout selected These are examined in the section titled Additional Considerations All Applications on page 9 Infrared Heater Selection Procedure Additional Selection Considerations Figure 9 1 Layout for Example 2 Clearances to Combustibles and Heat Affected Objects Additional Considerations All Applications The selection process described for Spot Partial Area and Total Building Heating applications while seemingly simple does not consider all variables in the design and layout of the infrared heating solution The following provides additional background information on factors to be considered when designing the solution Guidelines and limitations stated in the Installation a
24. nd Service Manuals must also be followed Mounting Height Building Obstructions e For lower mounting heights use a larger number of closely spaced units with lower input ratings e For high mounting heights use a smaller number of units with higher input ratings spaced further apart e Building obstructions such as overhead cranes lighting and utilities must be avoided Low Intensity Tube Length Considerations e Units with higher input ratings are certified for longer tube lengths while units with lower input ratings are certified for Clearances to combustible materials must be maintained including areas with stored or stacked materials See pages 4 and 5 for additional information Clearance to heat affected objects such as sprinkler heads must be considered Generally high intensity units or the burner and first tube section of the low intensity units should be kept at least 6 8 feet from the sprinkler head assuming the sprinkler head is not in the direct path of infrared radiant energy Availability of Utilities Gas and Electric Availability of gas and electric should be considered If electric service is difficult or costly to extend high intensity units with millivolt controls are an excellent choice as external electrical power is not required As shown in the figure for Example 2 multiple units can be positioned end to end for common venting and to reduce the amount of gas piping and electricity wiring required
25. ng is a brief description of each type of infrared heater High Intensity Units utilize a diamond faced ceramic tile burner for maximum heat transfer housed in a rugged aluminized steel frame The flame burns on the outer surface of the tile s with the infrared energy efficiently directed by a polished aluminum reflector mounted on the aluminized steel frame Source temperatures can range from 1800 F to 2200 F The units are certified for indoor use only and operate unvented A minimum positive air displacement of 4 CFM per 1000 Btu hr input for natural gas or 5 CFM per 1000 Btu hr input for propane gas is required for proper ventilation Figure 2 1 High Intensity Infrared Heater Low Intensity Low intensity units utilize an aluminized steel heat exchanger tube with a polished aluminum reflector that efficiently directs infrared energy The burner is mounted at one end opening of the tube and exhausts at the other end opening Tube systems are available in either straight or U tube configurations Source temperatures near the burner end of the tube system can reach 1200 F Units are available as pressurized type systems which provide a power exhauster mounted at the same end as the burner to force the products of combustion through the tube The units operate vented Units are for indoor or outdoor applications Figure 2 2 Low Intensity Infrared Heater Understanding Heat Spread and Throw Distribution Before sel
26. on and 1 x the mounting height 5 feet in the other direction For example if the unit is mounted at 25 feet above the floor then the spread will be 25 feet 5 feet 20 feet x 1 2 10 feet in one direction and 25 feet 5 feet 20 feet x 1 1 2 30 feet in the other direction The total throw would be 10 feet 30 feet 40 feet Selection of mounting angle is influenced by the application which will be discussed in a later section Figure 3 2 High Intensity Heat Distribution Throw 1 5H 10 gt 3 5H 35 o z D de oy Z 0 5H 10 0 0H 35 9 200 5 Low Intensity Heat Spread Distribution Heat spread width as shown in Figure 3 3 is dependant on both the mounting height and mounting angle The spread at floor level for a unit mounted at 0 is roughly twice the mounting height However someone occupying the edge of that space will feel very little heat To cover an entire area up to 5 feet high shoulder level for the average worker the mounting height should be approximately 5 feet above half the distance of the desired width For example if the shoulder height area width is to be 30 feet wide the mounting height should be approximately 20 feet above the floor 5 feet 2 x 30 feet 20 feet Note that the actual floor level spread will be approximately 40 feet but the infrared heat is negligible at the edge of that area Figure 3 3 Low Intensity Heat Spread Width
27. s of operation This must be accounted for in the installation to avoid alignment problems The following are remedies that when combined will allow proper operation during expansion contraction e Chain mounting minimum length per I amp S Manual e Flexible gas connectors e Tighten tube clamps to 50 ft lb e Overlap reflectors by 4 every other joint screwed Accessories The following accessories can simplify or improve the installation layout of the infrared heating solution e Chain mounting sets allow quick and easy hanging of the heaters Since low intensity tube lengths change during operation due to expansion and contraction chain mounting is required e Stainless steel flexible gas connectors when allowed by local codes allows for expansion and contraction of the heater without placing stress on the gas supply piping e Reflector extensions low intensity only can be used to concentrate radiant energy in a smaller area or to direct heat away from a wall if mounted at 0 next to a wall With all the infrared heater choices that Modine offers there is great flexibility in design options Table 11 1 on the following page summarizes some common application considerations for making a choice between different infrared heater types Infrared Heater Selection Procedure Additional Selection Considerations Table11 1 Typical Infrared Heater Selection Considerations Application High Intensity Low Intensity Spot Heat
28. se cancer birth defects or other reproductive harm Read the installation operating and maintenance instructions thoroughly before installing or servicing this equipment November 2015 DESIGN AND ENGINEERING GUIDE high and low intensity gas fired infrared heaters Typical Applications The following are typical examples of buildings that can benefit from infrared heating Manufacturing facilities Vehicle repair facilities Loading docks Aircraft hangars Indoor tennis courts Car washes Golf driving ranges Covered walkways Fire stations Stadium seating areas Vestibules may Use Infrared Significant energy cost reduction potential in spot heating applications Conventional warm air heating systems must warm the air and move it across the people to be heated If just a few workers are in a small area of a large open building this would require heating large volumes of air to accomplish a suitable comfort level However infrared heaters in that area would heat only objects including those workers Infrared installations may actually use lower thermostat settings as the radiant heat reaches the worker more effectively than forced air applications There is no air mover reducing electricity costs There is better worker comfort since there are no uncomfortable drafts or annoying fan or blower noise Temperature recovery is quick if cold air is introduced from open doors or windows A forced air heater must heat lar
29. solution comes down to the cost benefit ratio of comfort level versus equipment price Example 1 Qty 1 60 Foot Straight Tube System Approximate Tube Temp Across Tube System 60 Foot Straight Tube 30 Feet from Burner It s so warm here could handle cold fish all day l agree it s so nice feel so productive It s so cold here that heater is junk Example 2 Qty 2 30 Foot Straight Tube Systems Approximate Tube Temp Across Tube System Qty 2 30 Foot Straight Tubes 1000 800 600 400 200 ee 0 10 20 30 40 50 60 Feet from Burner F I m really happy my employer cares enough to keep me warm It s so warm here could handle cold fish all day It s not bad wish it was a little warmer Example 3 2 60 Foot U Tube Systems Approximate Tube Temp Across Tube System Qty 2 60 Foot U Tubes 30 Feet from Burner Pm really happy my employer cares enough to keep me warm It s so warm here could handle cold fish all day l agree it s so nice feel so productive 9 200 5 7 Infrared Heater Selection Procedure Total Building Heating Total Building Heating Total building heating applications involve replacing the building heat loss with at least the same amount of heat placed near the areas of greatest heat loss Total building heating applications w
30. stribution Low Intensity Heat Spread Distribution continued length The result is that tube temperatures start around 1000 to 1200 F on the burner end and fall to about 350 to 400 F on the opposite end the vent end For comfort radiant heating once the tube temperature falls along its length to approximately 600 F and below the radiant heat felt by occupants begins to decrease significantly The tube system still provides sensible heat to the space which is important for total building heating applications but for spot and partial area heating these temperatures would not provide adequate comfort levels The following typical tube temperature profiles will help in the discussion toward understanding which type of tube system configuration is appropriate with different applications 60 Foot Straight Tube System Example The following figure shows a typical tube system temperature profile for a 60 foot straight tube system The temperatures are adequate for comfort radiant heating to just over 40 feet Beyond that distance radiant heating will be negligible as the temperature falls below 600 F Figure 4 1 60 Ft Straight Tube Temperature Approximate Tube Temp Across Tube System 60 Foot Straight Tube 30 40 Feet from Burner Temperatures shown are for example purposes only Actual results may vary based on input rating gas heat value altitude etc 60 Foot U Tube System Example The following figur
31. tenance NOTE Units must NOT be separated combustion this arrangement will installed where they may be exposed to a minimize foreign particles entering the unit and potentially explosive or flammable atmosphere combustion process NOTE Units must NOT be installed where they may be exposed to a potentially explosive or flammable atmosphere Environments with Poor choice The controls are located externally Poor to Fair choice Units designed for outdoor Corrosive Chemicals and therefore are not protected from corrosion installations will aid in protecting the controls Present damage The aluminized steel frame and from the corrosive elements Outside reflector offers minimal protection from corrosive combustion air should be used to avoid elements significant corrosive elements from entering the unit and the combustion process However ambient side corrosion may significantly reduce the life of the unit which is not warranted Buildings with Poor Fair choice Unvented units in applications with Excellent choice for units that are vented Insulation poor insulation may experience excessive condensation on the inside of the building structure Proper ventilation is required Buildings with Negative Excellent choice Units operate unvented and Excellent choice Units operate with a power Pressure are unaffected by pressure differentials between exhauster and are able to overcome typical the heated space and the pressure outside the negativ
32. the surrounding area with forced air heat would not be practical Infrared heat is well suited for this application as the objects people would be heated and not the surrounding air The heat required for individual comfort varies with environmental physiological and even psychological variables Activity level room temperature relative air movement humidity and clothing all contribute to the comfort or discomfort of an individual It is also psychological since one person s perception of comfort is different than another person s perception There are various engineering principles and calculations that can be used to derive appropriate ratings for comfort spot heating However there is still the psychological factor that differs between people that cannot be easily accounted for in equations In lieu of working through complex formulas the following table can be used to approximate the model number required to meet the conditions of the application For spot heating high intensity heaters are the best choice It is preferable to use two heaters for heating people to ensure both the front and back sides are comfortable If it is impractical to use two heaters it is usually advisable to use one heater of the next higher model at an increased mounting height provided mounting height restrictions do not eliminate this option Table 6 1 shows three different ambient conditions Co d Drafty Air Average Calm Air and Warn Still Air T
33. tion Outdoor conditions can have a considerable effect on how the unit is perceived to be operating The following are several examples 10 9 200 5 e Considerable wind will cause a greater cooling effect on people thus requiring more heater input e f mounted above dirt floors re radiation typically seen from a concrete slab will be virtually non existent as the dirt floor will simply absorb the heat and conduct it away from the surface into the Earth Duration of Operation For spot or area heating operations the heaters are normally operating only while there are people in the area required to be heated This is often accomplished with an On Off switch For total building heating the heaters will cycle to maintain the temperature Often upon startup the heaters will run continuously for days as the building structure floors walls equipment etc rises to a steady state as required to maintain comfort temperature levels Once the space has been effectively heated the units will cycle normally It is important to note that for total building heating during unoccupied periods the heaters should not be turned off and the use of setback temperature minimized As stated in the previous paragraph it can take days for the building structure to become heated to properly maintain a comfortable space temperature Low Intensity Tube System Expansion Tube systems can expand contract by 1 6 based on heating and cooling cycle
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