Contents - Index


Enthalpy_Formation

 

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 25 C (77 F).  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 for Ideal Gas and Nasa Gas substances assume that the phase of the substance is gas.  The enthalpy of formation values provided for liquids in the Incompressible substances library assume that the substance is in liquid phase.

 

Examples:

 

$UnitSystem SI kJ molar

$Load Incompressible

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

h_ref_H2O=enthalpy_formation(H2O) {this result is for water vapor and it will be the same as enthalpy(H2O,T=T_ref)}

h_ref_propanol=Enthalpy_formation('n-Propanol') {data from the Incompressible fluid library provide enthalpy of formation for liquid phase}

 

{Solution

h_ref_CO2=-393486 [kJ/kmol]

h_ref_H2O=-241811 [kJ/kmol]

h_ref_propanol=-302540 [kJ/kmol]

}

 

Thermophysical Property Functions

LowerHeatingValue

HigherHeatingValue