.Buildings.Fluid.HeatExchangers.BaseClasses.ntu_epsilonZ

Information

This function computes the number of transfer units for a given heat exchanger effectiveness, capacity flow ratio and heat exchanger flow regime. The different options for the flow regime are declared in Buildings.Fluid.Types.HeatExchangerFlowRegime.

Note that for the flow regime CrossFlowUnmixed, computing the function requires the numerical solution of an equation in one variable. This is handled internally and not exposed to the global solver.

Interface

function ntu_epsilonZ
  input Real eps(min = 0, max = 0.999) "Heat exchanger effectiveness";
  input Real Z(min = 0, max = 1) "Ratio of capacity flow rate (CMin/CMax)";
  input Integer flowRegime "Heat exchanger flow regime";
  output Real NTU "Number of transfer units";
end ntu_epsilonZ;

Revisions

• February 7, 2025, by Jelger Jansen:
  Removed import statement. This is for IBPSA, #1961.
• February 28, 2020, by Michael Wetter:
  Replaced call to Media.Common.OneNonLinearEquation to use Modelica.Math.Nonlinear.solveOneNonlinearEquation because Media.Common.OneNonLinearEquation will be obsolete in MSL 4.0.0.
  This is for issue 1299.
• September 28, 2016, by Massimo Cimmino:
  Added case for constant temperature phase change on one side of the heat exchanger.
• July 7, 2014, by Michael Wetter:
  Changed the type of the input flowRegime from Buildings.Fluid.Types.HeatExchangerFlowRegime to Integer. This was done to have the same argument list as Buildings.Fluid.HeatExchangers.BaseClasses.epsilon_ntuZ, in which the type had to be changed.
• April 29, 2013, by Michael Wetter:
  Added dummy argument to function call of Internal.solve to avoid a warning during model check in Dymola 2015.
• August 10, 2011, by Michael Wetter:
  Changed implementation to use Modelica.Media.Common.OneNonLinearEquation instead of Buildings.Utilities.Math.BaseClasses.OneNonLinearEquation.
• February 11, 2010, by Michael Wetter:
  First implementation.