Maint 8.1.x issue3027 wet coil sensible heat (#3051)

* Updated release notes and date

* Added bug fix for #3027, updated releases notes and date

Buildings/Fluid/HeatExchangers/BaseClasses/HexElementLatent.mo

@@ -19,60 +19,47 @@ model HexElementLatent "Element of a heat exchanger with humidity condensation o
 
  MassExchange masExc(
  redeclare final package Medium=Medium2) "Model for mass exchange"
- annotation (Placement(transformation(extent={{50,-40},{70,-20}})));
+ annotation (Placement(transformation(extent={{-10,-10},{10,10}})));
 
 protected
  Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor temSen(
  T(final quantity="ThermodynamicTemperature",
  final unit = "K", displayUnit = "degC", min=0))
  "Temperature sensor of metal"
- annotation (Placement(transformation(extent={{-60,-10},{-40,10}})));
+ annotation (Placement(transformation(extent={{-60,-2},{-40,18}})));
  Buildings.HeatTransfer.Sources.PrescribedHeatFlow heaConVapAir
  "Heat conductor for latent heat flow rate, accounting for latent heat removed with vapor"
- annotation (Placement(transformation(extent={{0,-30},{-20,-10}})));
+ annotation (Placement(transformation(extent={{70,-10},{90,10}})));
  Modelica.Blocks.Math.Product pro
  "Product to compute the latent heat flow rate"
- annotation (Placement(transformation(extent={{60,-10},{40,10}})));
+ annotation (Placement(transformation(extent={{40,-10},{60,10}})));
  Modelica.Blocks.Sources.RealExpression h_fg(final y=Buildings.Utilities.Psychrometrics.Constants.h_fg)
  "Enthalpy of vaporization"
- annotation (Placement(transformation(extent={{90,-4},{70,16}})));
- Buildings.HeatTransfer.Sources.PrescribedHeatFlow heaConVapCoi
- "Heat conductor for latent heat flow rate, accounting for latent heat deposited with vapor on the coil"
- annotation (Placement(transformation(extent={{0,10},{-20,30}})));
- Modelica.Blocks.Math.Gain gain(final k=-1)
- annotation (Placement(transformation(extent={{30,10},{10,30}})));
+ annotation (Placement(transformation(extent={{-10,10},{10,30}})));
 equation
- connect(temSen.T, masExc.TSur) annotation (Line(points={{-40,0},{20,0},{20,
- -22},{48,-22}}, color={0,0,127}));
- connect(masExc.mWat_flow, vol2.mWat_flow) annotation (Line(points={{71,-30},{
- 80,-30},{80,-44},{44,-44},{44,-52},{14,-52}},
- color={0,0,127}));
- connect(vol2.X_w, masExc.XInf) annotation (Line(points={{-10,-64},{-20,-64},{
- -20,-44},{30,-44},{30,-30},{48,-30}},
- color={0,0,127}));
+ connect(temSen.T, masExc.TSur) annotation (Line(points={{-39,8},{-12,8}},
+ color={0,0,127}));
+ connect(vol2.X_w, masExc.XInf) annotation (Line(points={{-10,-64},{-24,-64},{
+ -24,0},{-12,0}}, color={0,0,127}));
  connect(Gc_2, masExc.Gc) annotation (Line(
- points={{40,-100},{40,-38},{48,-38}},
+ points={{40,-100},{40,-20},{-20,-20},{-20,-8},{-12,-8}},
  color={0,0,127},
  smooth=Smooth.None));
  connect(temSen.port, con1.solid) annotation (Line(
- points={{-60,0},{-66,0},{-66,60},{-50,60}},
+ points={{-60,8},{-66,8},{-66,60},{-50,60}},
  color={191,0,0},
  smooth=Smooth.None));
- connect(heaConVapAir.Q_flow, pro.y) annotation (Line(points={{0,-20},{0,-20},{
- 36,-20},{36,0},{39,0}}, color={0,0,127}));
- connect(masExc.mWat_flow, pro.u2) annotation (Line(points={{71,-30},{80,-30},
- {80,-6},{62,-6}},color={0,0,127}));
+ connect(masExc.mWat_flow, pro.u2) annotation (Line(points={{11,0},{26,0},{26,
+ -6},{38,-6}}, color={0,0,127}));
  connect(pro.u1, h_fg.y)
- annotation (Line(points={{62,6},{66,6},{69,6}},
+ annotation (Line(points={{38,6},{30,6},{30,20},{11,20}},
  color={0,0,127}));
- connect(heaConVapAir.port, con2.fluid) annotation (Line(points={{-20,-20},{-24,
- -20},{-24,-40},{-30,-40}}, color={191,0,0}));
- connect(heaConVapCoi.port, con2.solid) annotation (Line(points={{-20,20},{-66,
- 20},{-66,0},{-66,-40},{-50,-40}}, color={191,0,0}));
- connect(gain.y, heaConVapCoi.Q_flow)
- annotation (Line(points={{9,20},{6,20},{0,20}}, color={0,0,127}));
- connect(pro.y, gain.u) annotation (Line(points={{39,0},{36,0},{36,0},{36,20},{
- 32,20}}, color={0,0,127}));
+ connect(heaConVapAir.port, con2.fluid) annotation (Line(points={{90,0},{94,0},
+ {94,-40},{-30,-40}}, color={191,0,0}));
+ connect(masExc.mWat_flow, vol2.mWat_flow) annotation (Line(points={{11,0},{26,
+ 0},{26,-52},{14,-52}}, color={0,0,127}));
+ connect(pro.y, heaConVapAir.Q_flow) annotation (Line(points={{61,0},{70,0}},
+ color={0,0,127}));
  annotation (
  Documentation(info="<html>
 <p>
@@ -86,15 +73,23 @@ Buildings.Fluid.HeatExchangers.BaseClasses.PartialHexElement</a>
 for a description of the physics of the sensible heat exchange.
 For the latent heat exchange, this model removes water vapor from the air stream, as
 computed by the instance <code>masExc</code>. This effectively moves water vapor molecules
-out of the air, and deposits them on the coil. Hence, the latent heat that is carried
-by these water vapor molecules is removed from the air stream, and added to the coil
-surface. This is done using the heat flow sources <code>heaConVapAir</code> and
-<code>heaConVapWat</code>.
+out of the air, and deposits them on the coil from where it drains from the system.
+Hence, the latent heat that is carried
+by these water vapor molecules is removed from the air stream. This is done using the heat flow source <code>heaConVapAir</code>.
+</p>
+<p>
+Note that the driving potential for latent heat transfer is the temperature of the instance <code>mas</code>.
+This is an approximation as it neglects the thermal resistance of the water film that builds up on the coil.
 </p>
 </html>",
 revisions="<html>
 <ul>
 <li>
+May 26, 2022, by Michael Wetter:<br/>
+Removed addition of heat to <code>mas.T</code>.<br/>
+This is for <a href=\"https://github.com/lbl-srg/modelica-buildings/issues/3027\">#3027</a>.
+</li>
+<li>
 March 11, 2021, by Michael Wetter:<br/>
 Changed constant <code>simplify_mWat_flow</code> from protected to public because it is assigned by
 <a href=\"modelica://Buildings.Fluid.HeatExchangers.WetCoilCounterFlow\">Buildings.Fluid.HeatExchangers.WetCoilCounterFlow</a>.<br/>

Buildings/Fluid/HeatExchangers/WetCoilCounterFlow.mo

@@ -11,12 +11,11 @@ model WetCoilCounterFlow
  "Set to true to cause port_a.m_flow + port_b.m_flow = 0 even if mWat_flow is non-zero. Used only if Medium.nX > 1"
  annotation(HideResult=true);
 
- Modelica.SIunits.HeatFlowRate QSen2_flow = Q2_flow - QLat2_flow
+ Modelica.SIunits.HeatFlowRate QSen2_flow=Q2_flow - QLat2_flow
  "Sensible heat input into air stream (negative if air is cooled)";
 
- Modelica.SIunits.HeatFlowRate QLat2_flow=
- Buildings.Utilities.Psychrometrics.Constants.h_fg * mWat_flow
- "Latent heat input into air (negative if air is dehumidified)";
+ Modelica.SIunits.HeatFlowRate QLat2_flow=Buildings.Utilities.Psychrometrics.Constants.h_fg
+ *mWat_flow "Latent heat input into air (negative if air is dehumidified)";
 
  Real SHR(
  min=0,
@@ -25,8 +24,8 @@ model WetCoilCounterFlow
  noEvent(if (Q2_flow > 1E-6 or Q2_flow < -1E-6) then Q2_flow else 1)
  "Sensible to total heat ratio";
 
- Modelica.SIunits.MassFlowRate mWat_flow = sum(ele[i].vol2.mWat_flow for i in 1:nEle)
- "Water flow rate";
+ Modelica.SIunits.MassFlowRate mWat_flow=sum(ele[i].vol2.mWat_flow for i in 1
+  :nEle) "Water flow rate";
 
  annotation (
 defaultComponentName="cooCoi",
@@ -78,6 +77,14 @@ Buildings.Fluid.HeatExchangers.DryCoilCounterFlow</a> instead of this model.
 </html>", revisions="<html>
 <ul>
 <li>
+May 26, 2022, by Michael Wetter:<br/>
+Removed addition of heat to <code>mas.T</code> in
+<a href=\"Buildings.Fluid.HeatExchangers.BaseClasses.HexElementLatent\">
+Buildings.Fluid.HeatExchangers.BaseClasses.HexElementLatent</a>
+to correct latent heat exchange calculation.<br/>
+This is for <a href=\"https://github.com/lbl-srg/modelica-buildings/issues/3027\">#3027</a>.
+</li>
+<li>
 March 12, 2021, by Michael Wetter:<br/>
 Removed <code>final</code> declaration in redeclaration.<br/>
 This is for <a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2392\">#2392</a>.
@@ -184,11 +191,5 @@ First implementation.
  preserveAspectRatio=true,
  extent={{-100,-100},{100,100}},
  grid={2,2},
- initialScale=0.5), graphics={Text(
- extent={{60,72},{84,58}},
- textColor={0,0,255},
- textString="water-side"), Text(
- extent={{50,-32},{90,-38}},
- textColor={0,0,255},
- textString="air-side")}));
+ initialScale=0.5)));
 end WetCoilCounterFlow;

Buildings/Fluid/HeatExchangers/WetCoilDiscretized.mo

@@ -11,12 +11,11 @@ model WetCoilDiscretized
  temSen_1(m_flow_nominal=m1_flow_nominal),
  temSen_2(m_flow_nominal=m2_flow_nominal));
 
- Modelica.SIunits.HeatFlowRate QSen2_flow = Q2_flow - QLat2_flow
+ Modelica.SIunits.HeatFlowRate QSen2_flow=Q2_flow - QLat2_flow
  "Sensible heat input into air stream (negative if air is cooled)";
 
- Modelica.SIunits.HeatFlowRate QLat2_flow=
- Buildings.Utilities.Psychrometrics.Constants.h_fg * mWat_flow
- "Latent heat input into air (negative if air is dehumidified)";
+ Modelica.SIunits.HeatFlowRate QLat2_flow=Buildings.Utilities.Psychrometrics.Constants.h_fg
+ *mWat_flow "Latent heat input into air (negative if air is dehumidified)";
 
  Real SHR(
  min=0,
@@ -25,8 +24,8 @@ model WetCoilDiscretized
  noEvent(if (Q2_flow > 1E-6 or Q2_flow < -1E-6) then Q2_flow else 1)
  "Sensible to total heat ratio";
 
-  Modelica.SIunits.MassFlowRate mWat_flow = sum(hexReg[:].ele[:,:].vol2.mWat_flow)
-  "Water flow rate";
+ Modelica.SIunits.MassFlowRate mWat_flow=sum(hexReg[:].ele[:, :].vol2.mWat_flow)
+ "Water flow rate";
 
  annotation (
 defaultComponentName="cooCoi",
@@ -57,6 +56,14 @@ Modelica.Media.Air.MoistAir</a>.
 </html>", revisions="<html>
 <ul>
 <li>
+May 26, 2022, by Michael Wetter:<br/>
+Removed addition of heat to <code>mas.T</code> in
+<a href=\"Buildings.Fluid.HeatExchangers.BaseClasses.HexElementLatent\">
+Buildings.Fluid.HeatExchangers.BaseClasses.HexElementLatent</a>
+to correct latent heat exchange calculation.<br/>
+This is for <a href=\"https://github.com/lbl-srg/modelica-buildings/issues/3027\">#3027</a>.
+</li>
+<li>
 January 12, 2019, by Michael Wetter:<br/>
 Corrected wrong use of <code>each</code>.
 </li>