AM 11 Document
Contents
1. direct User specified Program calculated Mi Other notes Window transmission diffuse User specified Program calculated Ki Other notes Internal solar distribution User specified fixed to Calculated once by one or more surfaces O program m Calculated at each time step Mi Notes 12 iad r i z PIETS Solar radiation and its reflection are best calculated if the direct and diffuse radiation components are separated 3 r a r Ground reflection must be calculated especially for more highly glazed spaces such as atria Anistropic diffuse solar radiation models are generally considered superior Window transmission may be calculated by the program or the user may specify incidence angle dependent values For direct solar radiation incidence angle dependent transmission and reflection or absorption properties are necessary a single value is often used for diffuse radiation Correct specification for direct radiation is most important Software is available to calculate incidence angle dependent values if programs require users to specify these and databases are inadequate The distribution of internal solar radiation is usually important only where glazed areas are large surfaces have very different thermal mass or a number of surfaces are glazed The retransmission through other glazed surfaces can be very important for modelling e g conservatories or atria note the treatment of this effect 10 of 15 z2. enue AM 11 Document B2 3 Surface heat exchange Internal surfaces Combined convection and Separate convection and radiation coefficient Oo radiation networks KS Internal combined coefficients Fixed user defined m Program calculated once O Calculated at each time step O Notes Not applicable Internal convection coefficients Fixed user defined m Program calculated once O Calculated at each time step Notes Internal longwave exchange Star network E IntersuArface exchange Mi Notes External surfaces Combined convection and Separate radiation and radiation coefficient oO convection networks VI External combined coefficients Some programs calculate heat exchange between surfaces and the enclosed air using a coefficient which describes both the convective and longwave effects With such an approach the calculated space temperature is not a true air temperature it is often termed the enclosure temperature The true effects of highly asymmetric radiant environments e g a radiant ceiling panel are poorly predicted The approach is however adequate for most spaces and where long term energy use predictions are required Note whether the approach used for glazing is the same as that used for opaque surfaces Ignore if separate convective and radiant exchange networks are employed Ignore if combined coefficients used In reality coefficients vary depending on the surface to air temperature difference su
3. ation will help in the understanding of published literature especially about validation studies 2 of 15 l enteu AM 11 Document B1 2 Computer specification Platform and operating system PC Yes Mi No O MS dos O Windows 3 x O Windows 95 O Windows nt ps2 os2 Unix Yes O No Apple Macintosh Yes m No Comments Can be run from either the PC or the Server Machine with Control from a License Manager run from a server machine Processor storage and peripherals Processor speed 3 GHz recommended quad core Minimum RAM 1 GB recommended 2 gig Minimum disk space 10 GB Other devices Floppy disk Yes Oo No m cd rom drive Yes Mi No O Printer Yes Vv No O Plotter Yes Vv No O Digitising table Yes O No Mi Other Plotter is optional A LAN connection is required Other requirements Screen resolution gt 800x600 Internet connection required for update patches network connection required for license manager Suitable machines Most modern PCs will have no trouble running the software 3 f A Consider screen size video RAM Internet connection local area network connection etc List types of machine known to be suitable 3 of 15 l enteu AM 11 Document B1 3 Program code Type of code Compiled code only Yes No QO Source code available Yes O No Extra for source code Yes O No Programming language Fortran Mi C C Ea Notes B1 4 Modelling methods The Design Simulation program uses the EnergyPlus sim
4. h may account for wind speed direction and surface orientation is used Although a rigorous approach is theoretically preferable wind speeds and directions close to surfaces are difficult to calculate 3 Longwave heat loss to surroundings has a significant impact on the temperature of external surfaces and for glazed surfaces and other poorly insulated areas the temperature of the interior spaces This has a significant impact on the comfort conditions and perhaps the demands for heating in highly glazed spaces such as atria The exchange may be modelled by a single coefficient or a detailed algorithm may be adopted The algorithm may calculate exchange to both the sky and surrounding surfaces ground and buildings or to just the sky The method of calculating the sky temperature should be noted Heat input from plant and casual sources people lights and equipment may have fixed radiant and convective components or the user may be able to specify these The ability to specify will be important if for example a highly radiant source is used or if highly radiant sources are combined with convective sources The ability to specify the latent proportion of casual heat gains may be similarly important particularly regarding cooking equipment Some programs use detailed models e g which incorporate a time delay and an exponential temperature rise so that heating plant can be more accurately modelled This is less important for long term energ
5. l enteu AM 11 Document Introduction Bentley Hevacomps AM 11 document can be found below Please note that AM 11 is a statement about simulation software and is not an accredited item Appendix B Checklist for choosing BEEM software This checklist complements section 4 of the CIBSE Applications Manual AM11 1998 Building Energy and Environmental Modelling B1 General B1 1 Program description Name vendor origins Program name Design Simulation Version V2 Date of current release Feb 2008 Vendor s name Bentley Systems UK Ltd Contact name Stephen Brown Vendor s address Smithywood House Smithywood Crescent Sheffield S8 ONU Tel 0114 255 6680 Fax 0114 255 6638 E mail support hevacomp com Program type Thermal analysis Load calculation Vv Plant and controls VI Energy simulation MW Lighting and visualisation Electric lighting Mi Daylighting M Combined Ki Air movement m Specialist tool Further description i The classification of programs is explained in Section 2 A program may have a number of listed capabilities Space is provided to elucidate the description 1of15 z enue AM 11 Document Program history Description Design simulation was first produced in 2007 and incorporates Hevacomp CAD input The simulation engine is EnergyPlus List previous names by which program known significant advances in functionality and dates of these changes of platform and changes of vendors This inform
6. ociated databases Thermophysical properties Yes M No Oo Basic material properties Yes M No 0 Properties of complete construction Yes M No O Transmission of windows Yes M No O Comment Weather data Yes M No O Worldwide Yes M No o Number of sites 7900 Comment Other databases Check that the modules are available and working consult vendors about likely future releases Ask how many entries are in each database ask to see some of their contents 5 of 15 Bente AM 11 Document B1 9 User support Manuals User manual Yes M No O Hard copy ye O No On line Ys M No O Date of the latest copy February 2009 Does it include example problems with the expected answers Yes M No O Do the problems exercise all program modules ye OF No Does it explain how to use every module Yes M No O Comments Technical manual Yes M No O Hard copy ye OF No Ki On line Ys M No O On line help Ys WM No O Comments Case studies Vendor s case study examples obtained Yes M No O Case studies of others obtained Yes OF No Mi Hotline Hotline support Yes M No O Turn round Instant O 1day M gt 1 day O 10 i F oe Ask to see the manual Ensure that it contains all the useful features and that it is up to date 6 of 15 Bente AM 11 Document Software Updates provided Yes M No O Media for dissemination Floppy disk O CD Internet Training Courses provided Yes MW No m Cost from 350 Length Details available Frequenc
7. rface length or height roughness etc Note the algorithm used to describe these effects Ignore if combined coefficient used A star network balances radiation exchange at a fictitious central node Radiation actually occurs by intersurface exchange A view factor calculation is needed to describe the intersurface visibility Note whether exact or approximate view factors are used and whether the program calculates these The heat exchange at external surfaces may be calculated using a simple combined surface heat transfer coefficient or by separating out convection and radiation and modelling each of these in detail Note whether the approach used for glazing is the same as that used for opaque surfaces so 15 z enue AM 11 Document Fixed user defined O Program calculated once m Calculated at each time step 12 of 15 l enteu AM 11 Document External convection coefficients Fixed user defined m Program calculated once O Calculated at each time step Notes External longwave exchange User or program calculated coefficient O Detailed algorithm Ki Notes B2 4 Heating cooling and casual gains Heat input Combined radiant and Separate fixed radiant and convective O convective components Mi Notes Cooling Sensible cooling only O Sensible and latent cooling MW Notes If a separate treatment is adopted for external convection note whether a fixed coefficient is used or a more detailed algorithm whic
8. s is important Some programs are very flexible enabling minute by minute variations others are less flexible 14 of 15 Z sentey AM 11 Document B2 5 Observations 8 P siani r Record here any other general observations about the capabilities of the program which have not been covered elsewhere For example some programs impose geometric description limits on the maximum numbers of zones surfaces per zone or windows per surface 15 of 15
9. simulation programs theoretical basis B2 1 Conduction and thermal storage Solution method Explicit finite difference Implicit finite difference oO Respnse factor Weighting factors O Other Time step length User specified Calculated by program E Opaque surface conduction model One dimensional Three dimensional O Opaque layers node placement Fixed at number User specified O Not applicable m Other Glazing conduction model Resistance or U value O Multi layer with nodes Mi Other Air gaps User specified resistance O Program calculated resistance WI Other Initial node temperature User specified m Program calculated vi Notes 2 Preconditioning time User specified m Program recommended 11 ak PaT x r i r Validation work indicates that conduction and thermal storage are well modelled in the programs studied Alternative approaches generally have little impact on results and a small impact on program run times The ability to conduct three dimensional analyses is rarely needed For modelling a large area of glass especially heat absorbing glass windows are best modelled as multi layer constructions 9 of 15 z pene AM 11 Document B2 2 Solar radiation External solar radiation Direct and diffuse Separate treatment of combined Oo direct and diffuse K Ground reflection of radiation Considered Not considered oO Diffuse radiation sky model Isotropic m Anisotropic Ki Notes Window transmission
10. ulation engine B1 5 Input interface Type of interface GUI Menu driven m Command line O Other Digital data file Program produces accessible and human readable digital data files Yes M No 0 Legibility of digital file Good M Poor O Bad O Is entire problem definition contained Yes M No O Are all simulation parameters included Yes M No O Data checking Does program check for consistency and plausibility of input Yes M No O 3 Interfaces may generate files e g binary files which cannot be read by people but only by the program interface These are much less useful and old binary files may cease to be readable by new versions of the interface Check that all the data are included e g geometry construction and occupancy data and that the weather file used is noted Check that all the simulation control information such as time step length length of preconditioning and convergence criteria is given 4of 15 l enteu AM 11 Document B1 6 Output interface Type of interface GUI Tabular m Digital m Digital data Is digital output accessible Yes M No O Legibility of digital file Good M Poor O Bad O Is all output contained Yes M No O Are algorithm level outputs accessible Yes M No O B1 7 Linked modules CAD input Ys O No M Vendor s own interface Yes M No Oo Other cad system s name AutoCAD DXF files Comments The software uses AutoCAD DXF files as a template for inputting data B1 8 Ass
11. y calculations than for short term temperature predictions 5 An ability to calculate the latent cooling load will be particularly important in humid environments The ability to do this implies that the moisture content of the air is tracked by the program few programs do this 13 of 15 l enteu AM 11 Document Controlling plant Free float Yes M No 0 Idealised control Yes M No O Ideal preheat cool Yes M No O Fixed heat injection Yes M No O On off thermostat Yes M No O Accelerator Yes M No O Proportional Yes M No Oo Proportional plus integral Yes M No m Proportional plus integral plus derivative Yes M No E Advanced e g fuzzy logic adaptive self tuning neural network ye OF No Ki Other Schedules Repeated daily schedule Yes M No O Repeated hourly schedule Yes M No O Seasonal variations Yes M No O Flexible hourly schedule Yes M No 0 Notes Sensor types Sensing air temperature Yes M No Oo Mixed radiation and convection sensing Yes M No O Surface temperature sensing Yes OF No Ki Intraconstruction sensing Yes OF No Vv Notes 26 Most programs assume perfect control is possible i e that a specified set point can be quickly achieved provided plant capacities are sufficient this is usually adequate for long term energy calculations In some programs the impact on temperature of alternative forms of control can be explored The ability to schedule heating and cooling plant and the occurrence of internal heat gain
12. y Details available B1 10 User base Numbers Users in UK 10 500 Users worldwide 11 800 Sites in UK 1 500 Sites worldwide 1 630 UK building services engineers UK architects UK builders UK others 10 500 Is there a user club Yes O No Ki Contacts Name Support and Sales Address Bentley Systems UK Ltd Smithywood House Smithywood Crescent Sheffield S8 ONU Tel 0114 255 6680 Fax 0114 255 6638 E mail support hevacomp com 7 of 15 l enteu AM 11 Document B1 11 Cost Software and associated databases Core program 2000 first seat 1000 additional seats Modules Name Name Name Databases Name Name First year user licence fee Total software and data Computer Name Annual recurring licence fee after first year of use Typical training course fees per year B1 12 Accuracy Has the program been evaluated Yes M No O Does the vendor exercise routine in house quality testing Yes M No O Complete the table below to document the validation history Independently i Date tested or by vendor v Type of test A C E Source of information Comments on the results Aug 07 i E CLG Part L Accreditation test Nov 07 i A ASHRAE HVAC Tests Nov 07 i A ASHRAE Fabric tests Nov 07 i A ASHRAE 120 Nov 07 i A BESTest A Analytical verification C Intermodel comparison E Empirical validation 8of 15 l enteu AM 11 Document B2 Thermal
Download Pdf Manuals
Related Search