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 BuildingSystems.Fluid.Types.HeatExchangerFlowRegime.
function epsilon_C input Modelica.Units.SI.ThermalConductance UA "UA value"; input Modelica.Units.SI.ThermalConductance C1_flow "Enthalpy flow rate medium 1"; input Modelica.Units.SI.ThermalConductance C2_flow "Enthalpy flow rate medium 2"; input Integer flowRegime "Heat exchanger flow regime, see BuildingSystems.Fluid.Types.HeatExchangerFlowRegime"; input Modelica.Units.SI.ThermalConductance CMin_flow_nominal "Minimum enthalpy flow rate at nominal condition"; input Modelica.Units.SI.ThermalConductance CMax_flow_nominal "Maximum enthalpy flow rate at nominal condition"; input Real delta = 1E-3 "Small value used for smoothing"; output Real eps(min = 0, max = 1) "Heat exchanger effectiveness"; end epsilon_C;
Z
and NTU
as they are not used by other models.
Removed if
statement that can cause a discontinuous derivative.
flowRegime
from
BuildingSystems.Fluid.Types.HeatExchangerFlowRegime
to Integer
.
This was done to have the same argument list as
BuildingSystems.Fluid.HeatExchangers.BaseClasses.epsilon_ntuZ,
in which the type had to be changed.
import
statement.