Derivative of function BuildingSystems.Utilities.Psychrometrics.Functions.pW_X.
function der_pW_X extends Modelica.Icons.Function; input Modelica.Units.SI.MassFraction X_w(min = 0, max = 1, nominal = 0.01) "Species concentration at dry bulb temperature"; input Modelica.Units.SI.Pressure p = 101325 "Total pressure"; input Real dX_w "Differential of species concentration at dry bulb temperature"; input Real dp "Differential of total pressure"; output Real dp_w "Differential of water vapor pressure"; end der_pW_X;