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Transparent,validated, highly accurate HVAC System Design Algorithms

Link our Spreadsheet Design Modules into a comprehensive computing system - no need for manual input data transferring and editing the calculations any more. For example, if the architect changed the window type, just change the U-value as needed and immediately read the size of all air-handling unit elements, ducts, even piping serving the spaces with new windows. Do your math and rip the benefits of reduced time and improved accuracy in everyday HVAC Systems engineering!

Learn how to swiftly create self-contained open-code computational systems with ease! No programming knowledge or experience required, as you will be unleashing the power of MS Excel!

Module 'Design Loads'

ParameterTest sourceUnitsActualSimulatedDeviation
Solar irradiance Single-room example, p.30.32 /1/ Btu/h/ft2 205.4 205.4 0%
Solar-temperature same oF 156 156.4 0%
Lighting cooling load same Btu/h 1122 1123 0%
Wall cooling load same Btu/h 602 572 5.2%
Cooling load of windows without blinds same Btu/h 5636 5542 1.4%
Cooling load of windows with blinds same Btu/h 4310 4254 1.1%
Room heat loss same Btu/h 8495 8513 -0.2%

Module 'Water Flow'

Friction loss rates in ft w.c./100ft at 60oF water flow rate 10 US gal/min
Duct diameter, in.Test sourceSource valueBy module (Galvanized steel)By module (Uncoated carbon steel)
¾ Friction chart /1/ 25.0 23.9 20.8
1 same 7.0 7.04 6.32
1 ¼ same 1.8 1.79 1.65
1 1/2 same 0.9 0.83 0.78
Duct diameter, in.Test sourceActualBy module (Galvanized steel)By module (Uncoated carbon steel)
2 Friction chart /1/ 19 19.06 16.27
2 ½ same 7.2 7.69 6.69
3 same 2.5 2.56 2.28
4 same 0.52 0.65 0.6
Average deviations for using galvanized steel and carbon steel are 0% and -11%, respectively. Chapter 2 /1/ states that the module’s formulae are more accurate than the chart.

Module 'Psychrometrics'

ParameterTest sourceUnitsActualPredictedDeviation
Atmospheric pressure Chapter 6 /1/ In. Me 29.921 29.921 0%
Dry-bulb temperature same oF 100 100 0%
Wet-bulb temperature same oF 65 65 0%
Humidity ratio same lb/lb 0.0052 0.0053 -2%
Enthalpy same Btu/hlb 29.8 29.8 0%
Relative humidity same % 13 13 0%
Specific volume same ft3/lb 14.22 14.25 0%
Dew-point temperature same oF 40 40.3 -1%

Module 'Thermal Comfort'

ParameterTest sourceUnitsTest #1Test #2Test #3Test #4
Metabolic heat production Appendix D /4/ met 1.1 1.1 1.1 1.1
Insulation of clothing same clo 1.0 1.0 1.0 1.0
Indoor air temperature same oC 19.6 23.9 25.7 21.2
Indoor air temperature same % 86.0 66.0 15.0 20.0
Mean radiant temperature same oC 19.6 23.9 25.7 21.2
Air velocity same m/s 0.1 0.1 0.1 0.1
Actual PMV same -0.5 0.5 0.5 -0.5
PMV by module -0.47 0.49 0.54 -0.45
Actual PPD same 10% 10% 10% 10%
PPD by module 10% 10% 11% 9%
Metabolic heat production Appendix D /4/ met 1.1 1.1 1.1 1.1
Insulation of clothing same clo 0.5 0.5 0.5 0.5
Indoor air temperature same oC 23.6 26.8 27.9 24.7
Indoor air temperature same % 67.0 56.0 13.0 16.0
Mean radiant temperature same oC 23.6 26.8 27.9 24.7
Air velocity same m/s 0.1 0.1 0.1 0.1
Actual PMV same -0.5 0.5 0.5 -0.5
PMV by module -0.46 0.55 0.52 -0.46
Actual PPD same 10% 10% 10% 10%
PPD by module 9% 11% 11% 9%

Module 'Air Flow'

Duct diameter, in.Test sourceUnitsActualBy moduleDeviation
26 Chapter 35 /1/ Inch w.c./100ft 0.08 0.08 0%
22 same same 0.195 0.190 3%
18 same same 0.50 0.52 -4%
14 same same 1.99 1.85 7%
Average deviation is 1.5%.