01 Unit System
IP uses °F, BTU/lb dry air, ft³/lb dry air, and psia. SI uses °C, kJ/kg dry air, m³/kg dry air, and kPa.
02 Input Pair
Only sufficient HVAC pairs are exposed. Dry bulb stays in the mix because thermodynamics enjoys making under-defined states look tempting.
03 Known Values
04 Altitude / Pressure
Pressure uses standard atmosphere altitude correction. Leave altitude at zero for sea-level ASHRAE chart comparisons.
Moist-Air State
SOLVED FROMDry Bulb + Relative Humidity
Equation basis: ASHRAE Fundamentals Chapter 1 Hyland-Wexler saturation pressure equations, humidity ratio from vapor partial pressure, IP/SI enthalpy equations, ASHRAE gas-law specific volume, dew point and wet bulb solved iteratively.
All Psychrometric Properties
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Calculation Breakdown
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