This information is part of the Modelica Standard Library maintained by the Modelica Association.

This function calculates the specific enthalpy of R134a for an isentropic pressure change from refState.p to p_downstream (e.g., use setState_phX function for input of refState).

The function can be used for instance to calculate an isentropic efficiency of a compressor or calculate the power consumption (obtained from the isentropic enthalpy) for a given efficiency.

Example:

  Medium.AbsolutePressure p_downstream=10e5;
  Medium.SpecificEnthalpy h_downstream=4.1e5;
  Medium.AbsolutePressure p_upstream=3e5;
  Medium.SpecificEnthalpy h_upstream=4.0e5;

  // Isentropic efficiency of a compressor:
  Real eta_is;

equation

  h_is = isentropicEnthalpy(p_downstream, Medium.setState_phX(p_upstream, h_upstream));

  eta_is = (h_is-h_upstream)/(h_downstream - h_upstream);

Restrictions

The isentropic efficiency function should not be applied in liquid region.

h_is = isentropicEnthalpy(p_downstream, refState)

p_downstream	Type: AbsolutePressure (Pa) Description: Downstream pressure
refState	Type: ThermodynamicState Description: Reference state for entropy

h_is	Type: SpecificEnthalpy (J/kg) Description: Isentropic enthalpy