functionepsilon_C

Computes heat exchanger effectiveness for given capacity flow rates and heat exchanger flow regime

Information

This function computes the heat exchanger effectiveness, the Number of Transfer Units, and the capacity flow ratio for given capacity flow rates.

The implementation allows for zero flow rate. As CMin_flow crosses delta*CMin_flow_nominal from above, the Number of Transfer Units and the heat exchanger effectiveness go to zero.

The different options for the flow regime are declared in AixLib.Fluid.Types.HeatExchangerFlowRegime.

Inputs

TypeNameDefaultDescription
Modelica.Units.SI.ThermalConductanceUAUA value
Modelica.Units.SI.ThermalConductanceC1_flowEnthalpy flow rate medium 1
Modelica.Units.SI.ThermalConductanceC2_flowEnthalpy flow rate medium 2
IntegerflowRegimeHeat exchanger flow regime, see AixLib.Fluid.Types.HeatExchangerFlowRegime
Modelica.Units.SI.ThermalConductanceCMin_flow_nominalMinimum enthalpy flow rate at nominal condition
Modelica.Units.SI.ThermalConductanceCMax_flow_nominalMaximum enthalpy flow rate at nominal condition
Realdelta1E-3Small value used for smoothing

Outputs

TypeNameDefaultDescription
RealepsHeat exchanger effectiveness

Revisions

  • January 10, 2018, by Michael Wetter:
    Removed outputs Z and NTU as they are not used by other models. Removed if statement that can cause a discontinuous derivative.
  • July 7, 2014, by Michael Wetter:
    Changed the type of the input flowRegime from AixLib.Fluid.Types.HeatExchangerFlowRegime to Integer. This was done to have the same argument list as AixLib.Fluid.HeatExchangers.BaseClasses.epsilon_ntuZ, in which the type had to be changed.
  • July 6, 2014, by Michael Wetter:
    Removed unused import statement.
  • February 20, 2010, by Michael Wetter:
    First implementation.