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Air-Side Energy Use Calculations for Four HVAC Systems: Dual Duct Constant Volume (DDCAV), Dual Duct Variable Volume (DDVAV), Constant Volume with Reheat (CAVRH0), Variable Volume with Reheat (VAVRH)
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This report contains engineering calculations for four (4) air-side, heating, ventilating and air-conditioning systems (HVAC) systems, including: dual duct constant volume (DDCAV), dual duct variable volume (DDVAV), constant volume with reheat (CAVRH), and variable volume with reheat (VAVRH). These calculations are presented in spreadsheets that include a running commentary so that the reader can trace through the calculations to see what is being performed. Each system also contains a one-line diagram that shows the system being simulated and the location of the variables used in the calculation.
DescriptionThese calculations are useful for developing educational materials, and can be used to check the values obtained from a computer simulation program that contain the exact same schematic as is shown for each system. With only a few exceptions, the formulas for the calculations have come from the ASHRAE Handbook, as indicated in the spreadsheet narrative. These spreadsheets were developed in Lotus *.wkl format and can be run in any spreadsheet that accepts Lotus *.wkl format. To use the spreadsheets, the user loads the spreadsheet, updates only the values needed and recalculates the spreadsheet manually. Calculations are repeated column-wise in the spreadsheet to reach convergence. Each calculation represents one set of conditions. To obtain answers for multiple conditions, the user will need to enter the new conditions and recalculate for each set of conditions.
- Technical Reports 
Haberl, J. S. (2001). Air-Side Energy Use Calculations for Four HVAC Systems: Dual Duct Constant Volume (DDCAV), Dual Duct Variable Volume (DDVAV), Constant Volume with Reheat (CAVRH0), Variable Volume with Reheat (VAVRH). Energy Systems Laboratory (http://esl.tamu.edu), Texas A&M University. Available electronically from