Absolute humidity per unit mass of moist air at saturation is computed from density and temperature in the state record. Note, that this mass fraction refers to mass of moist air at saturation.
function Xsaturation
extends Modelica.Icons.Function;
input ThermodynamicState state "Thermodynamic state record";
output MassFraction X_sat "Steam mass fraction of sat. boundary";
end Xsaturation;