modelConstantEffectiveness

Heat and moisture exchanger with constant effectiveness

Extends from IDEAS.Fluid.HeatExchangers.BaseClasses.PartialEffectiveness.

Information

Model for a heat and moisture exchanger with constant effectiveness.

This model transfers heat and moisture in the amount of 

  QSen = epsS * Q_max,
  m    = epsL * mWat_max,

where epsS and epsL are constant effectiveness for the sensible and latent heat transfer, Q_max is the maximum sensible heat that can be transferred and mWat_max is the maximum moisture that can be transferred.

For a sensible heat exchanger, use IDEAS.Fluid.HeatExchangers.ConstantEffectiveness instead of this model.

This model can only be used with medium models that define the integer constant Water which needs to be equal to the index of the water mass fraction in the species vector.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.EfficiencyepsS0.8Sensible heat exchanger effectiveness
Modelica.Units.SI.EfficiencyepsL0.8Latent heat exchanger effectiveness

Components

TypeNameDefaultDescription
Modelica.Units.SI.HeatFlowRateQLat_flowLatent heat exchange from medium 2 to medium 1
Medium1.MassFractionX_w_in1Inlet water mass fraction of medium 1
Medium2.MassFractionX_w_in2Inlet water mass fraction of medium 2
Modelica.Units.SI.MassFlowRatemWat_flowWater flow rate from medium 2 to medium 1
Modelica.Units.SI.MassFlowRatemMax_flowMaximum water flow rate from medium 2 to medium 1

Revisions

  • April 30, 2018, by Filip Jorissen:
    Set final prescribedHeatFlowRate1=true and final prescribedHeatFlowRate2=true.
    See #907.
  • April 11, 2017, by Michael Wetter:
    Corrected bug as Q1_flow did not include latent heat flow rate.
    This is for issue Buildings #704.
  • October 14, 2013 by Michael Wetter:
    Replaced access to constant Medium1.Water by introducing the parameter i1_w, and used a similar construct for Medium2. This avoids an error during model check as these constants are not known in the partial medium model.
  • August 13, 2013 by Michael Wetter:
    Corrected error in the documentation.
  • July 30, 2013 by Michael Wetter:
    Updated model to use new variable mWat_flow in the base class.
  • January 28, 2010, by Michael Wetter:
    Added regularization near zero flow.
  • October 21, 2008, by Michael Wetter:
    First implementation, based on IDEAS.Fluid.HeatExchangers.ConstantEffectiveness.