density derivative by specific enthalpy
function ddhp_props extends Modelica.Icons.Function; input SI.Pressure p "pressure"; input SI.SpecificEnthalpy h "specific enthalpy"; input ThermalSeparation.Media.WaterBasedLiquid.BaseClasses.Common.IF97BaseTwoPhase aux "auxiliary record"; output SI.DerDensityByEnthalpy ddhp "density derivative by specific enthalpy"; end ddhp_props;