HA_PROPS_SI

This function evaluates a humid-air property using CoolProp’s psychrometric solver from three independent state inputs. It supports common variables such as dry-bulb temperature, pressure, relative humidity, humidity ratio, enthalpy, and dew-point temperature.

Humid air state evaluation is represented as a multivariable mapping:

y = f\left(o,\; n_1, v_1,\; n_2, v_2,\; n_3, v_3\right)

where o is the requested output property code, each n_i is an input property code, and each v_i is its SI value.

Excel Usage

=HA_PROPS_SI(ha_psi_out, ha_psi_name_one, value_one, ha_psi_name_two, value_two, ha_psi_name_three, value_three)

• ha_psi_out (str, required): Desired property code (e.g., ‘H’, ‘W’, ‘Vda’).
• ha_psi_name_one (str, required): Name of first input (e.g., ‘T’).
• value_one (float, required): Value of first input.
• ha_psi_name_two (str, required): Name of second input (e.g., ‘P’).
• value_two (float, required): Value of second input.
• ha_psi_name_three (str, required): Name of third input (e.g., ‘R’, ‘W’).
• value_three (float, required): Value of third input.

Returns (float): Calculated property value in SI units.

Example 1: Enthalpy of standard air (25C, 1atm, 50% RH)

Inputs:

ha_psi_out	ha_psi_name_one	value_one	ha_psi_name_two	value_two	ha_psi_name_three	value_three
H	T	298.15	P	101325	R	0.5

Excel formula:

=HA_PROPS_SI("H", "T", 298.15, "P", 101325, "R", 0.5)

Expected output:

50423.5

Example 2: Humidity Ratio (W)

Inputs:

ha_psi_out	ha_psi_name_one	value_one	ha_psi_name_two	value_two	ha_psi_name_three	value_three
W	T	298.15	P	101325	R	0.5

Excel formula:

=HA_PROPS_SI("W", "T", 298.15, "P", 101325, "R", 0.5)

Expected output:

0.00992574

Example 3: Dew Point Temperature

Inputs:

ha_psi_out	ha_psi_name_one	value_one	ha_psi_name_two	value_two	ha_psi_name_three	value_three
Tdp	T	298.15	P	101325	R	0.5

Excel formula:

=HA_PROPS_SI("Tdp", "T", 298.15, "P", 101325, "R", 0.5)

Expected output:

287.017

Example 4: Volume per unit dry air

Inputs:

ha_psi_out	ha_psi_name_one	value_one	ha_psi_name_two	value_two	ha_psi_name_three	value_three
Vda	T	303.15	P	101325	R	0.8

Excel formula:

=HA_PROPS_SI("Vda", "T", 303.15, "P", 101325, "R", 0.8)

Expected output:

0.88837

Python Code

Show Code

import CoolProp.CoolProp as CP

def ha_props_si(ha_psi_out, ha_psi_name_one, value_one, ha_psi_name_two, value_two, ha_psi_name_three, value_three):
    """
    Calculate humid air properties using CoolProp psychrometrics.

    See: https://coolprop.org/coolprop/HighLevelAPI.html#hapropssi-function

    This example function is provided as-is without any representation of accuracy.

    Args:
        ha_psi_out (str): Desired property code (e.g., 'H', 'W', 'Vda'). Valid options: Temperature (T), Pressure (P), Humidity Ratio (W), Relative Humidity (R), Dew Point (Tdp), Wet Bulb (Twb), Enthalpy (H), Entropy (S), Mixture Volume (V), Dry Air Volume (Vda), Viscosity (M), Conductivity (K).
        ha_psi_name_one (str): Name of first input (e.g., 'T'). Valid options: Temperature (T), Pressure (P), Humidity Ratio (W), Relative Humidity (R), Dew Point (Tdp), Wet Bulb (Twb), Enthalpy (H).
        value_one (float): Value of first input.
        ha_psi_name_two (str): Name of second input (e.g., 'P'). Valid options: Temperature (T), Pressure (P), Humidity Ratio (W), Relative Humidity (R), Dew Point (Tdp), Wet Bulb (Twb).
        value_two (float): Value of second input.
        ha_psi_name_three (str): Name of third input (e.g., 'R', 'W'). Valid options: Temperature (T), Pressure (P), Humidity Ratio (W), Relative Humidity (R), Dew Point (Tdp), Wet Bulb (Twb).
        value_three (float): Value of third input.

    Returns:
        float: Calculated property value in SI units.
    """
    try:
        # CoolProp.HAPropsSI(Output, Name1, Prop1, Name2, Prop2, Name3, Prop3)
        result = CP.HAPropsSI(ha_psi_out, ha_psi_name_one, value_one, ha_psi_name_two, value_two, ha_psi_name_three, value_three)
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

ha_psi_out * Select... Temperature (T) Pressure (P) Humidity Ratio (W) Relative Humidity (R) Dew Point (Tdp) Wet Bulb (Twb) Enthalpy (H) Entropy (S) Mixture Volume (V) Dry Air Volume (Vda) Viscosity (M) Conductivity (K)

Desired property code (e.g., 'H', 'W', 'Vda').

ha_psi_name_one * Select... Temperature (T) Pressure (P) Humidity Ratio (W) Relative Humidity (R) Dew Point (Tdp) Wet Bulb (Twb) Enthalpy (H)

Name of first input (e.g., 'T').

value_one *

Value of first input.

ha_psi_name_two * Select... Temperature (T) Pressure (P) Humidity Ratio (W) Relative Humidity (R) Dew Point (Tdp) Wet Bulb (Twb)

Name of second input (e.g., 'P').

value_two *

Value of second input.

ha_psi_name_three * Select... Temperature (T) Pressure (P) Humidity Ratio (W) Relative Humidity (R) Dew Point (Tdp) Wet Bulb (Twb)

Name of third input (e.g., 'R', 'W').

value_three *

Value of third input.