record IF97BaseTwoPhase "Intermediate property data record for IF 97"
    extends Modelica.Icons.Record;

    Integer phase(start = 0) "Phase: 2 for two-phase, 1 for one phase, 0 if unknown";
    Integer region(min = 1, max = 5) "IF 97 region";
    SI.Pressure p "Pressure";
    SI.Temperature T "Temperature";
    SI.SpecificEnthalpy h "Specific enthalpy";
    SI.SpecificHeatCapacity R "Gas constant";
    SI.SpecificHeatCapacity cp "Specific heat capacity";
    SI.SpecificHeatCapacity cv "Specific heat capacity";
    SI.Density rho "Density";
    SI.SpecificEntropy s "Specific entropy";
    DerPressureByTemperature pt "Derivative of pressure w.r.t. temperature";
    DerPressureByDensity pd "Derivative of pressure w.r.t. density";
    Real vt "Derivative of specific volume w.r.t. temperature";
    Real vp "Derivative of specific volume w.r.t. pressure";
    Real x "Dryness fraction";
    Real dpT "dp/dT derivative of saturation curve";
end IF97BaseTwoPhase;