.Buildings.Utilities.Psychrometrics.Functions.phi_pTX

Information

Relative humidity of air for given pressure, temperature and water vapor mass fraction.

Note that the water vapor mass fraction must be in kg/kg total air, and not dry air.

Interface

function phi_pTX
  extends Modelica.Icons.Function;
  input Modelica.Units.SI.Pressure p "Absolute pressure of the medium";
  input Modelica.Units.SI.Temperature T "Dry bulb temperature";
  input Modelica.Units.SI.MassFraction X_w "Water vapor mass fraction per unit mass total air";
  output Real phi(unit = "1") "Relative humidity";
end phi_pTX;

Revisions

• April 4, 2019 by Filip Jorissen:
  Added inverse annotation for #1110.
• November 17, 2014 by Michael Wetter:
  Removed test that constrains the saturation pressure to be lower than p. I do not see any numerical problems without this test.
• November 13, 2014 by Michael Wetter:
  First implementation.