Contents - Index



ENTHALPY_FORMATION [kJ/kg, kJ/kmol, J/kg, J/kmol, Btu/lbm Btu/lbmol] returns the specific enthalpy of the specified substance at a reference temperature of 25C (77F).  This enthalpy value is based on a reference state in which elements in their natural state at the reference temperature have zero enthalpy. The units of the value returned by this function depend on the user settings of the unit system.   


This function is implemented for ideal gases, the NASA gases and organic incompressible fluids.


The ENTHALPY_FORMATION function requires only one argument and that is the name of the substance.  The function is not applicable for real fluids or brines.


The value of the enthalpy of formation depends on the phase of the substance.  The values returned by this function assume that that the phase is what it would be at the reference temperature and standard atmospheric pressure.  




$UnitSystem SI kJ molar

h_ref_CO2=enthalpy_formation(CO2)  {same as enthalpy(CO2,T=T_ref)}

h_ref_H2O=enthalpy_formation(H2O) {this result is for liquid water and will thus differ from enthalpy(H2O,T=T_ref)}

h_ref_propanol=Enthalpy_formation('n-Propanol') {data from the Incompressible fluid library}



h_ref_CO2=-393486 [kJ/kmol]

h_ref_H2O=-285813 [kJ/kmol]

h_ref_propanol=-302540 [kJ/kmol]



Thermophysical Property Functions