Contents - Index



CV [J/kg-K, J/kmol-K, kJ/kg-K, kJ/kmol-K, Btu/lbm-R, Btu/lbmol-R] returns the constant volume specific heat of the specified substance.  The value and units returned depend on the setting in the Unit System dialog.  For pure substances that obey the ideal gas law and incompressible substances, the CV function has temperature as its only other argument in addition to the substance name.  For pure real fluids, two independent arguments are required.  Note that, at saturation, pressure and temperature are not independent.  If the constant volume specific heat of saturated liquid or vapor is required, it is necessary to provide the quality or some other quality-dependent property.  The constant volume specific heat of a two-phase mixture with a quality other than 0 or 1 is infinite and a value cannot be returned for this state.  


For AirH2O, three arguments are required for the CV function.  One of these arguments must be total pressure (P).  The remaining two can be any of the following: temperature (T), enthalpy (H), relative humidity (R), humidity ratio (W), wetbulb (B), or dewpoint (D).   X (for quality) is not allowed.  Note also that the specific heat returned for substance AirH2O (psychrometrics) is per unit mass of dry air.


Note that, for  incompressible substances, CV, CP and SPECHEAT all return the same result.


The list of property identifiers needed in the calling arguments and instructions are available in the Thermophysical Function help.


See also:  SPECHEAT and CP,