HA_PROPS_AUX
This function exposes CoolProp’s auxiliary humid-air property evaluator, which provides low-level coefficients and thermophysical terms used internally by psychrometric calculations.
It evaluates an auxiliary property as a function of dry-bulb temperature, pressure, and humidity ratio:
y = f\left(o, T, p, w\right)
where o is the requested auxiliary output code, T is temperature in kelvin, p is pressure in pascals, and w is humidity ratio in kg water per kg dry air.
Excel Usage
=HA_PROPS_AUX(output_name, temperature, pressure, humidity_ratio)output_name(str, required): Auxiliary output code for humid-air calculations.temperature(float, required): Dry-bulb temperature (K).pressure(float, required): Total pressure (Pa).humidity_ratio(float, required): Humidity ratio (kg/kg dry air).
Returns (float): Auxiliary humid-air property value.
Example 1: Saturated vapor pressure at standard conditions
Inputs:
| output_name | temperature | pressure | humidity_ratio |
|---|---|---|---|
| p_ws | 298.15 | 101325 | 0.01 |
Excel formula:
=HA_PROPS_AUX("p_ws", 298.15, 101325, 0.01)Expected output:
3169.75
Example 2: Enhancement factor near ambient condition
Inputs:
| output_name | temperature | pressure | humidity_ratio |
|---|---|---|---|
| f | 300 | 101325 | 0.012 |
Excel formula:
=HA_PROPS_AUX("f", 300, 101325, 0.012)Expected output:
1.00433
Example 3: First virial air-air coefficient
Inputs:
| output_name | temperature | pressure | humidity_ratio |
|---|---|---|---|
| Baa | 295 | 101325 | 0.008 |
Excel formula:
=HA_PROPS_AUX("Baa", 295, 101325, 0.008)Expected output:
-0.00000874799
Example 4: Molar saturated volume of water vapor
Inputs:
| output_name | temperature | pressure | humidity_ratio |
|---|---|---|---|
| vbar_ws | 310 | 101325 | 0.015 |
Excel formula:
=HA_PROPS_AUX("vbar_ws", 310, 101325, 0.015)Expected output:
0.000018136
Python Code
Show Code
import CoolProp.CoolProp as CP
def ha_props_aux(output_name, temperature, pressure, humidity_ratio):
"""
Compute auxiliary humid-air properties from CoolProp.
See: https://www.coolprop.org/apidoc/CoolProp.CoolProp.html
This example function is provided as-is without any representation of accuracy.
Args:
output_name (str): Auxiliary output code for humid-air calculations. Valid options: Baa, Caaa, Bww, Cwww, Baw, Caww, Caaw, beta_H, kT, vbar_ws, p_ws, f.
temperature (float): Dry-bulb temperature (K).
pressure (float): Total pressure (Pa).
humidity_ratio (float): Humidity ratio (kg/kg dry air).
Returns:
float: Auxiliary humid-air property value.
"""
try:
value, _units = CP.HAProps_Aux(output_name, temperature, pressure, humidity_ratio)
return float(value)
except Exception as e:
return f"Error: {str(e)}"