Corrected boundary condition and initial conditions for #2488 (#2490)

* Corrected boundary condition and initial conditions for #2488 * Updated reference results due to #2488
lbl-srg · May 18, 2021 · 1b16c3d · 1b16c3d
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diff --git a/...s/Applications/DataCenters/ChillerCooled/Equipment/Validation/BaseClasses/PartialPlant.mo b/...s/Applications/DataCenters/ChillerCooled/Equipment/Validation/BaseClasses/PartialPlant.mo
@@ -25,10 +25,10 @@ partial model PartialPlant
         transformation(
         extent={{10,-10},{-10,10}},
         origin={80,-4})));
-  Buildings.Fluid.Sources.MassFlowSource_T sou1(
+  Fluid.Sources.Boundary_pT sou1(
+    p=MediumCW.p_default + 45E3,
     use_T_in=true,
     redeclare package Medium = MediumCW,
-    m_flow=mCW_flow_nominal,
     T=298.15)
     "Source on medium 1 side"
     annotation (Placement(transformation(extent={{-60,-14},{-40,6}})));
@@ -83,6 +83,14 @@ Buildings.Applications.DataCenters.ChillerCooled.Equipment.Validation</a>.
 </html>", revisions="<html>
 <ul>
 <li>
+May 13, 2021, by Michael Wetter:<br/>
+Changed boundary condition model to prescribed pressure rather than prescribed mass flow rate.
+Prescribing the mass flow rate caused
+unreasonably large pressure drop because the mass flow rate was forced through a closed valve.<br/>
+This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2488\">#2488</a>.
+</li>
+<li>
 September 11, 2017, by Michael Wetter:<br/>
 Corrected wrong use of replaceable model.<br/>
 This is for

diff --git a/.../DataCenters/ChillerCooled/Equipment/Validation/CoolingCoilHumidifyingHeating_OpenLoop.mo b/.../DataCenters/ChillerCooled/Equipment/Validation/CoolingCoilHumidifyingHeating_OpenLoop.mo
@@ -19,7 +19,7 @@ model CoolingCoilHumidifyingHeating_OpenLoop
     allowFlowReversal1=true,
     allowFlowReversal2=true,
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
-    yValve_start=0,
+    yValve_start=0.2,
     tauEleHea=1,
     tauHum=1,
     m1_flow_nominal=m1_flow_nominal,
@@ -89,6 +89,13 @@ for different inlet conditions.
 </html>", revisions="<html>
 <ul>
 <li>
+May 13, 2021, by Michael Wetter:<br/>
+Set start value of valve to avoid unreasonably large pressure drop due to prescribed mass flow
+rate that was forced through a closed valve.<br/>
+This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2488\">#2488</a>.
+</li>
+<li>
 April 11, 2017, by Yangyang Fu:<br/>
 First implementation.
 </li>

diff --git a/...gs/Applications/DataCenters/ChillerCooled/Equipment/Validation/ElectricChillerParallel.mo b/...gs/Applications/DataCenters/ChillerCooled/Equipment/Validation/ElectricChillerParallel.mo
@@ -1,19 +1,28 @@
 within Buildings.Applications.DataCenters.ChillerCooled.Equipment.Validation;
 model ElectricChillerParallel "Model that test electric chiller parallel"
   extends Modelica.Icons.Example;
-  extends Buildings.Fluid.Chillers.Examples.BaseClasses.PartialElectric(
-      P_nominal=-per1.QEva_flow_nominal/per1.COP_nominal,
-      mEva_flow_nominal=per1.mEva_flow_nominal,
-      mCon_flow_nominal=per1.mCon_flow_nominal,
-      sou1(nPorts=1, m_flow=2*mCon_flow_nominal),
-      sou2(nPorts=1, m_flow=2*mEva_flow_nominal));
+
+  package Medium1 = Buildings.Media.Water "Medium model";
+  package Medium2 = Buildings.Media.Water "Medium model";
+
+  parameter Modelica.SIunits.Power P_nominal = -per1.QEva_flow_nominal/per1.COP_nominal
+    "Nominal compressor power (at y=1)";
+  parameter Modelica.SIunits.TemperatureDifference dTEva_nominal=10
+    "Temperature difference evaporator inlet-outlet";
+  parameter Modelica.SIunits.TemperatureDifference dTCon_nominal=10
+    "Temperature difference condenser outlet-inlet";
+  parameter Real COPc_nominal = 3 "Chiller COP";
+  parameter Modelica.SIunits.MassFlowRate mEva_flow_nominal = per1.mEva_flow_nominal
+    "Nominal mass flow rate at evaporator";
+  parameter Modelica.SIunits.MassFlowRate mCon_flow_nominal = per1.mCon_flow_nominal
+    "Nominal mass flow rate at condenser";
 
   parameter Buildings.Fluid.Chillers.Data.ElectricEIR.ElectricEIRChiller_McQuay_WSC_471kW_5_89COP_Vanes
     per1 "Chiller performance data"
-    annotation (Placement(transformation(extent={{60,80},{80,100}})));
+    annotation (Placement(transformation(extent={{60,50},{80,70}})));
   parameter Buildings.Fluid.Chillers.Data.ElectricEIR.ElectricEIRChiller_York_YT_563kW_10_61COP_Vanes
     per2 "Chiller performance data"
-    annotation (Placement(transformation(extent={{32,80},{52,100}})));
+    annotation (Placement(transformation(extent={{32,50},{52,70}})));
   Buildings.Applications.DataCenters.ChillerCooled.Equipment.ElectricChillerParallel chiPar(
     num=2,
     redeclare package Medium1 = Medium1,
@@ -25,27 +34,107 @@ model ElectricChillerParallel "Model that test electric chiller parallel"
     dpValve_nominal={6000,6000},
     per={per1,per2})
     "Chillers with identical nominal parameters but different performance curves"
-    annotation (Placement(transformation(extent={{-10,0},{10,20}})));
+    annotation (Placement(transformation(extent={{-10,-30},{10,-10}})));
+  Fluid.Sources.Boundary_pT sou1(
+    redeclare package Medium = Medium1,
+    p=Medium1.p_default + 18E3,
+    use_T_in=true,
+    T=298.15,
+    nPorts=1) "Pressure boundary condition"
+    annotation (Placement(transformation(extent={{-80,-24},{-60,-4}})));
+  Fluid.Sources.Boundary_pT sou2(
+    redeclare package Medium = Medium2,
+    p=Medium2.p_default + 18E3,
+    use_T_in=true,
+    T=291.15,
+    nPorts=1) "Pressure boundary condition"
+    annotation (Placement(transformation(extent={{80,-40},{60,-20}})));
+  Buildings.Fluid.Sources.Boundary_pT sin1(
+    redeclare package Medium = Medium1, nPorts=1) "Pressure boundary condition"
+    annotation (Placement(
+        transformation(
+        extent={{10,-10},{-10,10}},
+        origin={70,10})));
+  Buildings.Fluid.Sources.Boundary_pT sin2(
+    redeclare package Medium = Medium2, nPorts=1) "Pressure boundary condition"
+    annotation (Placement(
+        transformation(
+        extent={{-10,-10},{10,10}},
+        origin={-70,-50})));
+  Modelica.Blocks.Sources.Ramp TSet(
+    duration=3600,
+    startTime=3*3600,
+    offset=273.15 + 10,
+    height=8) "Set point for leaving chilled water temperature"
+    annotation (Placement(transformation(extent={{-80,20},{-60,40}})));
+  Modelica.Blocks.Sources.Ramp TCon_in(
+    height=10,
+    offset=273.15 + 20,
+    duration=3600,
+    startTime=2*3600) "Condenser inlet temperature"
+    annotation (Placement(transformation(extent={{-120,-20},{-100,0}})));
+  Modelica.Blocks.Sources.Ramp TEva_in(
+    offset=273.15 + 15,
+    height=5,
+    startTime=3600,
+    duration=3600) "Evaporator inlet temperature"
+    annotation (Placement(transformation(extent={{120,-36},{100,-16}})));
+  Modelica.Blocks.Sources.Pulse pulse(period=3600/2)
+   "Pulse input signal"
+    annotation (Placement(transformation(extent={{-80,50},{-60,70}})));
+  Modelica.Blocks.Logical.GreaterThreshold greaterThreshold(threshold=0.5)
+    "Switch to switch chiller on or off"
+    annotation (Placement(transformation(extent={{-40,50},{-20,70}})));
+  Buildings.Fluid.FixedResistances.PressureDrop res1(
+    redeclare package Medium = Medium1,
+    m_flow_nominal=mCon_flow_nominal,
+    dp_nominal=6000) "Flow resistance"
+    annotation (Placement(transformation(extent={{32,0},{52,20}})));
+  Buildings.Fluid.FixedResistances.PressureDrop res2(
+    dp_nominal=6000,
+    redeclare package Medium = Medium2,
+    m_flow_nominal=mEva_flow_nominal) "Flow resistance"
+    annotation (Placement(transformation(extent={{-20,-60},{-40,-40}})));
+
 equation
   connect(chiPar.port_b1, res1.port_a)
-    annotation (Line(points={{10,16},{20,16},
-          {20,40},{32,40}}, color={0,127,255}));
-  connect(chiPar.port_a1, sou1.ports[1])
-    annotation (Line(points={{-10,16},{-26,16},{-40,16}}, color={0,127,255}));
+    annotation (Line(points={{10,-14},{20,-14},{20,10},{32,10}},
+                            color={0,127,255}));
   connect(res2.port_a, chiPar.port_b2)
-    annotation (Line(points={{-20,-20},{-16,-20},
-          {-16,4},{-10,4}}, color={0,127,255}));
-  connect(chiPar.port_a2, sou2.ports[1])
-    annotation (Line(points={{10,4},{26,4},{40,4}}, color={0,127,255}));
+    annotation (Line(points={{-20,-50},{-16,-50},{-16,-26},{-10,-26}},
+                            color={0,127,255}));
   connect(greaterThreshold.y, chiPar.on[1])
-    annotation (Line(points={{-19,90},{-16,90},{-16,13},{-12,13}},
+    annotation (Line(points={{-19,60},{-16,60},{-16,-17},{-12,-17}},
       color={255,0,255}));
   connect(greaterThreshold.y, chiPar.on[2])
-    annotation (Line(points={{-19,90},{-16,90},{-16,15},{-12,15}},
+    annotation (Line(points={{-19,60},{-16,60},{-16,-15},{-12,-15}},
       color={255,0,255}));
   connect(TSet.y, chiPar.TSet)
-    annotation (Line(points={{-59,60},{-28,60},{-28,10},{-12,10}},
+    annotation (Line(points={{-59,30},{-28,30},{-28,-20},{-12,-20}},
       color={0,0,127}));
+
+  connect(TCon_in.y, sou1.T_in) annotation (Line(
+      points={{-99,-10},{-82,-10}},
+      color={0,0,127},
+      smooth=Smooth.None));
+  connect(TEva_in.y, sou2.T_in) annotation (Line(
+      points={{99,-26},{82,-26}},
+      color={0,0,127},
+      smooth=Smooth.None));
+
+  connect(greaterThreshold.u, pulse.y) annotation (Line(
+      points={{-42,60},{-59,60}},
+      color={0,0,127},
+      smooth=Smooth.None));
+
+  connect(res1.port_b, sin1.ports[1]) annotation (Line(points={{52,10},{56,10},{
+          56,10},{60,10}}, color={0,127,255}));
+  connect(sou1.ports[1], chiPar.port_a1)
+    annotation (Line(points={{-60,-14},{-10,-14}}, color={0,127,255}));
+  connect(res2.port_b, sin2.ports[1]) annotation (Line(points={{-40,-50},{-50,-50},
+          {-50,-50},{-60,-50}}, color={0,127,255}));
+  connect(chiPar.port_a2, sou2.ports[1]) annotation (Line(points={{10,-26},{20,-26},
+          {20,-30},{60,-30}}, color={0,127,255}));
   annotation (    __Dymola_Commands(file=
           "modelica://Buildings/Resources/Scripts/Dymola/Applications/DataCenters/ChillerCooled/Equipment/Validation/ElectricChillerParallel.mos"
         "Simulate and plot"),
@@ -56,6 +145,14 @@ This example demonstrates how the chiller parallel can operate under different p
 </html>", revisions="<html>
 <ul>
 <li>
+May 13, 2021, by Michael Wetter:<br/>
+Changed boundary condition model to prescribed pressure rather than prescribed mass flow rate.
+Prescribing the mass flow rate caused
+unreasonably large pressure drop because the mass flow rate was forced through a closed valve.<br/>
+This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2488\">#2488</a>.
+</li>
+<li>
 July 10, 2017, by Yangyang Fu:<br/>
 First implementation.
 </li>
@@ -64,5 +161,7 @@ First implementation.
 experiment(
       StartTime=0,
       StopTime=14400,
-      Tolerance=1e-06));
+      Tolerance=1e-06),
+    Diagram(coordinateSystem(extent={{-140,-100},{140,100}})),
+    Icon(coordinateSystem(extent={{-100,-100},{100,100}})));
 end ElectricChillerParallel;
diff --git a/Buildings/Applications/DataCenters/ChillerCooled/Equipment/Validation/ElectricHeater.mo b/Buildings/Applications/DataCenters/ChillerCooled/Equipment/Validation/ElectricHeater.mo
@@ -47,5 +47,7 @@ April 11, 2017 by Yangyang Fu:<br/>
 First implementation.
 </li>
 </ul>
-</html>"));
+</html>"),
+    Diagram(coordinateSystem(extent={{-100,-100},{120,100}})),
+    Icon(coordinateSystem(extent={{-100,-100},{100,100}})));
 end ElectricHeater;
diff --git a/...lications/DataCenters/ChillerCooled/Equipment/Validation/HeatExchanger_ResetController.mo b/...lications/DataCenters/ChillerCooled/Equipment/Validation/HeatExchanger_ResetController.mo
@@ -39,11 +39,11 @@ model HeatExchanger_ResetController
         transformation(
         extent={{10,-10},{-10,10}},
         origin={78,70})));
-  Buildings.Fluid.Sources.MassFlowSource_T sou1(
+  Fluid.Sources.Boundary_pT sou1(
+    p=MediumW.p_default + 60E3,
     use_T_in=true,
     nPorts=3,
     redeclare package Medium = MediumW,
-    m_flow=3*m1_flow_nominal,
     T=298.15)
     "Source on medium 1 side"
     annotation (Placement(transformation(extent={{-60,66},{-40,86}})));
@@ -79,11 +79,11 @@ model HeatExchanger_ResetController
     k(unit="K",displayUnit="degC")=273.15+16.56)
     "Leaving chilled water temperature setpoint"
     annotation (Placement(transformation(extent={{-90,40},{-70,60}})));
-  Buildings.Fluid.Sources.MassFlowSource_T sou2_1(
+  Fluid.Sources.Boundary_pT sou2_1(
+    p=MediumW.p_default + 50E3,
     nPorts=3,
     redeclare package Medium = MediumW,
-    use_T_in=true,
-    m_flow=3*m2_flow_nominal)
+    use_T_in=true)
     "Source on medium 2 side"
     annotation (Placement(transformation(extent={{60,14},{40,34}})));
   Modelica.Blocks.Sources.Constant TEva_in(k=273.15 + 25.28)
@@ -158,16 +158,18 @@ equation
     annotation (Line(points={{79,28},{62,28}}, color={0,0,127}));
   connect(TSen2.port_a, hex2.port_b2)
     annotation (Line(points={{-40,-70},{-12,-70}}, color={0,127,255}));
-  connect(sou1.ports[2], hex2.port_a1) annotation (Line(points={{-40,76},{-22,76},
-          {-22,-58},{-12,-58}}, color={0,127,255}));
+  connect(sou1.ports[2], hex2.port_a1) annotation (Line(points={{-40,76},{-22,
+          76},{-22,-58},{-12,-58}},
+                                color={0,127,255}));
   connect(hex2.port_b1, sin1.ports[2]) annotation (Line(points={{8,-58},{20,-58},
           {20,70},{68,70}}, color={0,127,255}));
   connect(TSet.y, hex2.TSet) annotation (Line(points={{-69,50},{-62,50},{-62,60},
           {-20,60},{-20,-60},{-14,-60}}, color={0,0,127}));
   connect(tri.y, hex1.trigger)
     annotation (Line(points={{-69,10},{-8,10},{-8,46}}, color={255,0,255}));
-  connect(sou2_1.ports[2], hex2.port_a2) annotation (Line(points={{40,24},{28,24},
-          {28,-70},{8,-70}}, color={0,127,255}));
+  connect(sou2_1.ports[2], hex2.port_a2) annotation (Line(points={{40,24},{28,
+          24},{28,-70},{8,-70}},
+                             color={0,127,255}));
   connect(sin2.ports[3], TSen3.port_b) annotation (Line(points={{-72,-44.6667},
           {-66,-44.6667},{-66,-156},{-50,-156}},color={0,127,255}));
   connect(TSen3.port_a, hex3.port_b2)
@@ -196,6 +198,14 @@ This example demonstrates how the PID controller in the heat exchanger model can
 </html>", revisions="<html>
 <ul>
 <li>
+May 13, 2021, by Michael Wetter:<br/>
+Changed boundary condition model to prescribed pressure rather than prescribed mass flow rate.
+Prescribing the mass flow rate caused
+unreasonably large pressure drop because the mass flow rate was forced through a closed valve.<br/>
+This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2488\">#2488</a>.
+</li>
+<li>
 January 28, 2019, by Yangyang Fu:<br/>
 First implementation.
 </li>

diff --git a/.../Applications/DataCenters/ChillerCooled/Equipment/Validation/IntegratedPrimaryLoadSide.mo b/.../Applications/DataCenters/ChillerCooled/Equipment/Validation/IntegratedPrimaryLoadSide.mo
@@ -3,7 +3,7 @@ model IntegratedPrimaryLoadSide
   "Integrated WSE on the load side in a primary-only chilled water system"
   extends Modelica.Icons.Example;
   extends Buildings.Applications.DataCenters.ChillerCooled.Equipment.Validation.BaseClasses.PartialPlant(
-    sou1(nPorts=2, m_flow=2*mCW_flow_nominal),
+    sou1(nPorts=2),
     sin1(nPorts=2),
     TSet(k=273.15 + 5.56),
     TEva_in(k=273.15 + 15.28),

diff --git a/...Applications/DataCenters/ChillerCooled/Equipment/Validation/IntegratedPrimaryPlantSide.mo b/...Applications/DataCenters/ChillerCooled/Equipment/Validation/IntegratedPrimaryPlantSide.mo
@@ -3,7 +3,7 @@ model IntegratedPrimaryPlantSide
   "Integrated WSE on the plant side in a primary-only chilled water system"
   extends Modelica.Icons.Example;
   extends Buildings.Applications.DataCenters.ChillerCooled.Equipment.Validation.BaseClasses.PartialPlant(
-    sou1(nPorts=2, m_flow=2*mCW_flow_nominal),
+    sou1(nPorts=2),
     sin1(nPorts=2),
     TSet(k=273.15 + 5.56),
     TEva_in(k=273.15 + 15.28),
@@ -40,12 +40,11 @@ model IntegratedPrimaryPlantSide
     y=if not onChi.y and onWSE.y then 1 else 0)
     "On/off signal for valve 6"
     annotation (Placement(transformation(extent={{40,60},{20,80}})));
-  Buildings.Fluid.Sources.MassFlowSource_T sou2(
+  Fluid.Sources.Boundary_pT sou2(
     redeclare package Medium = MediumCHW,
+    p=MediumCHW.p_default + 1E5,
     nPorts=2,
-    use_T_in=true,
-    m_flow=2*mCHW_flow_nominal)
-                   "Source on medium 2 side"
+    use_T_in=true) "Source on medium 2 side"
     annotation (Placement(
         transformation(
         extent={{10,-10},{-10,10}},
@@ -90,8 +89,8 @@ equation
           -20,-44},{-40,-44}}, color={0,127,255}));
   connect(intWSEPri1.port_b1, sin1.ports[1]) annotation (Line(points={{10,-32},{
           20,-32},{20,-4},{70,-4}}, color={0,127,255}));
-  connect(intWSEPri1.port_a2, sou2.ports[1]) annotation (Line(points={{10,-44},{
-          26,-44},{26,-72},{40,-72}},          color={0,127,255}));
+  connect(intWSEPri1.port_a2, sou2.ports[1]) annotation (Line(points={{10,-44},
+          {26,-44},{26,-72},{40,-72}},         color={0,127,255}));
   connect(TEva_in.y, sou2.T_in)
     annotation (Line(points={{69,-70},{62,-70}},          color={0,0,127}));
   connect(TSet.y, intWSEPri1.TSet) annotation (Line(points={{-79,30},{-16,30},{-16,
@@ -102,8 +101,8 @@ equation
           {-18,-30.4},{-11.6,-30.4}}, color={255,0,255}));
   connect(sou1.ports[2], intWSEPri2.port_a1) annotation (Line(points={{-40,-4},{
           -28,-4},{-28,-102},{-10,-102}}, color={0,127,255}));
-  connect(sou2.ports[2], intWSEPri2.port_a2) annotation (Line(points={{40,-76},{
-          26,-76},{26,-114},{10,-114}}, color={0,127,255}));
+  connect(sou2.ports[2], intWSEPri2.port_a2) annotation (Line(points={{40,-76},
+          {26,-76},{26,-114},{10,-114}},color={0,127,255}));
   connect(intWSEPri2.port_b1, sin1.ports[2]) annotation (Line(points={{10,-102},
           {20,-102},{20,-4},{70,-4}}, color={0,127,255}));
   connect(TSet.y, intWSEPri2.TSet) annotation (Line(points={{-79,30},{-16,30},{-16,
@@ -137,6 +136,14 @@ is reset every 1800s.
 </html>", revisions="<html>
 <ul>
 <li>
+May 13, 2021, by Michael Wetter:<br/>
+Changed boundary condition model to prescribed pressure rather than prescribed mass flow rate.
+Prescribing the mass flow rate caused
+unreasonably large pressure drop because the mass flow rate was forced through a closed valve.<br/>
+This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/2488\">#2488</a>.
+</li>
+<li>
 January 28, 2019, by Yangyang Fu:<br/>
 Added test case for PI controller reset.
 </li>