HVAC Load Explorerp V1.0 http://www.mae.okstate.edu/hvac/ p Dr. Ahmed Farouk Elsafty Mechanical and Marine Eng. Dept. College of Engineering and Technology Arab Academy for Science, Technology and Maritime Transport Email: [email protected] Content Notes • • • • • • • • • • • • • • • • • Minimum Requirements Weather data (explain selection and non-July) Zoning (“rooms”) Geometric description (inside dimensions or outside dimensions? Also simplification.) M t i l properties Material ti (i (include l d radiative di ti properties) ti ) Describing walls and roofs. Describing stud walls. How to describe attic type spaces. Describing windows Describing doors Internal heat gains (levels and schedules) D Describing ibi th thermall mass Infiltration and Ventilation Specifying system parameters Practical things about program –why why does it do backup instead of save? How to get output. Download latest version from website. Heating Load Calculations Check end of chapter for other items? Minimum System Requirements * Windows 95 * Pentium Pentium-compatible compatible processor running at 100 MHz or faster * 32MB RAM * Hard drive with at least 30MB free space * SVGA monitor,, 800 x 600 * Windows-compatible mouse or pointing device * CD-ROM drive * Adobe Acrobat(tm) Reader 3 (Adobe Acrobat Reader 4.0 included on CD) • The heat balance method is the most scientifically precise method now available.HVAC Load Explorer • This software uses the heat balance methods • Developed under ASHRAE Research Project 875 875. . for calculating cooling/heating loads in building. . and zone air. interior zone surfaces. air • Assures conservation of energy (which is not guaranteed for approximate methods).Heat Balance Method • Based on heat balances for exterior zone surfaces. LW Long Wave SW Short Wave . DoubleDouble click on the file "ar40eng.exe" and follow the instructions. • Insert the CD-ROM in yyour CD-ROM drive • In Windows Explorer. running close all applications. install • Double-click on the file "Setup.exe". locate the CD-ROM drive and go into the directory containing the program that you wish to install. • Follow the instructions in the installer.)) • If you do not have Adobe Acrobat. (This may require re-booting b i your computer.Software Setup • Start your computer. use the Windows Explorer to find the root directory of the CD. • Restart your computer. computer If your computer is already running. . Try now to Run the program Unfortunately. the program will not RUN !!!! Y need You d to t gett some files fil to t solve l this thi problem . . . . . . (Most will go into the HVACLoadExplorer directory. 29 2003) If you have installed the software from the CD.) If you have already downloaded a previous version from this website. you should copy the files into the specified directories. you will need to download the files listed below. under d your main i HVACL HVACLoadExplorer dE l di directory. You should right-click on each file name and choose "Save Target A " (in As" (i Mi Microsoft ft Explorer) E l ) or "Save "S Link Li k A As"" (i (in N Netscape). and have not previously downloaded any of the software.19. under your main HVACLoadExplorer directory.HVAC Load Explorer • • • • • Summary of Revisions and Known Bugs (New: 2-21-03) 2 21 03) Load Calculations Seminar (New 10-17-03) Download latest version (1. t ) th then save th the file in a temporary directory. (1 0 19 October 29.0. you should check the dates on the files below. TimeZone.txt must be copied into the textfiles di directory.mdb l db must be copied into the Database directory.template. When all files have been downloaded. . Any files listed below that are newer than the files on your hard drive should be downloaded. txt (New 12-1-00) HVAC Load Explorer\textfiles p template.mdb (New 4-28-03) HVAC Load Explorer\database Add d Addendum.exe (New 10-29-03) HVAC Load Explorer HVACLOADEXPLORE R.pdf df (N 22-21-03) (New 21 03) * .cnt (New 10 10-29-03) 29 03) HVAC Load Explorer HBFORT15.dll (New 2-21-03) HVAC Load Explorer DFORRT.Download: File Name Date Directory HvacLoadExplorer.HLP (New 10-29-03) HVAC Load Explorer HvacLoadExplorer cnt HvacLoadExplorer.DLL (New 6-1-00) HVAC Load Explorer TimeZone. Solution : Computers that do not already have the file mschrt20.ocx.C:\WINDOWS\system32 To download the file.C:\WINDOWS\system Windows NT/2000 .C:\WINNT\system32 y Windows Me .• • • • • • • Note: (4 (4-1-03) 1 03) Some computers may also need an additional file file.. right-click g on the link above and choose "Save Target As" (in Microsoft Explorer) or "Save Link As" (in Netscape) .C:\WinMe\System Windows Xp .ocx mschrt20 ocx will need to download the file. mschrt20. depending on your operating system: Windows 95/98 . and then store it in the following directory. mdb • The 9 room Chicago g office building g ((see Load Calculations Seminar) is here.edu spitler@okstate ed . • Bug Reports • Bugs should be reported to Prof.D. J.Download a Sample File • Thi This fil file can b be used d tto calculated l l t d th the conduction transfer function coefficients for Example 8-1: Example 8-1. Spitler at spitler@okstate. Load Calculations Heat Balance Method -Application Application . • See 2001 ASHRAE Handbook of Fundamentals for further information. • Based on peak wet bulb: cooling towers towers. ventilation • Based on peak dew dew-point: point: humidity control.Weather Data: Cooling Three types Th t off design d i days d • Based on p peak dry y bulb temperature: p room loads. . evaporative coolers. th even JJanuary. • Example: a p e Sout South facing ac g hotel ote rooms oo s with t large windows may have peak loads in January.Weather Data: Cooling • Month: Usually July July. • Some rooms can have peak loads in other months. January . but not always always. South-Facing South Facing Window • Simple scheme: window collects energy energy. insulation does not let it go. thermal mass stabilizes against large fluctuations – overhang defeats mechanism for summer months . )) • Zone: provided in HVAC Load Explorer for convenience. and controls. All rooms served by a single i l air i h handler) dl ) . loading. – IIn large l b ildi buildings. it may be b desirable d i bl tto combine bi multiple rooms into a single room description.g. i it iis a way off adding ddi up lloads d ffor a group of rooms. (e.Zoning/Rooms In HVAC Load Explorer terminology: • Room: one or more rooms with similar temperatures. – (Often called a zone in heat balance literature literature. Dimensions • Outside or Inside? • Corner effects are usually small small. . • Outside dimensions may slightly overestimate load load. • Simplify geometry when possible. • Inside I id dimensions di i may slightly li htl underestimate load. hence it doesn’t make that much difference. .Describing Walls and Roofs • Described layer by layer from the outside in. properties p for each layer y ((k. • Surface tilt and orientation must be specified for solar radiation purposes. ρ cp) p) from • Material p MPS 127-132 • Solar absorptivity and thermal emissivity important for inside and outside layers. • Do not specify surface conductances in heat balance method. ρ. Zone North Axis: . • Default is 90o.Wall Information Dialog Box • Tilt is the angle made by the wall with the g horizontal in degrees. 90o Elevation . – West facing direction will have facing direction 270°. E S .. direction. in degrees. – East facing wall will have facing direction of 90°. – South facing wall will have facing direction of 180°.Wall Information Dialog Box Facing F i direction di ti iis th the angle l made d b by the normal vector of wall with the north in the clockwise direction north. N W – Default is 0 0°(facing (facing north) north). 0° Roof 0° – Floor of 180 180°. Floor 180° .Roof and floor Information – Roof R f default d f lt is i 0°. but no sun • TB: special. .External Boundary Condition IImportant!! • TOS: normal outside conditions • TA: conditioned space on other side • TG: TG ground d temperature t t on other side • TSS: outside temperature. p . user-defined boundary temperature on other side. p • Necessarily approximate. interior partitions not elsewhere described.Thermal mass • Represents interior furnishings. • Has H ttwo effects: ff t – Thermal storage g ((slows room response) p ) – Radiative/convective exchange (speeds room response) . . Example .