From d169b5ee0f78818f24adbaf32b44075a44a5c846 Mon Sep 17 00:00:00 2001
From: Michael Wetter <mwetter@lbl.gov>
Date: Thu, 17 Oct 2024 14:21:24 -0700
Subject: [PATCH 1/3] Merged IBPSA, issue1921_organicRankineCycle

---
 Buildings/.copiedFiles.txt                    |  48 ++
 .../BaseClasses/FixedEvaporating.mo           |   4 +-
 .../BaseClasses/InterpolateStates.mo          |   4 +-
 .../BaseClasses/Validation/WetFluid.mo        |   4 +-
 .../OrganicRankine/ConstantEvaporation.mo     | 504 ++++++++++++++++++
 .../Fluid/CHPs/OrganicRankine/Data/Generic.mo |   4 +-
 .../Data/WorkingFluids/Acetone.mo             |   4 +-
 .../Data/WorkingFluids/Ethanol.mo             |   4 +-
 .../Data/WorkingFluids/Heptane.mo             |   4 +-
 .../Data/WorkingFluids/Pentane.mo             |   4 +-
 .../Data/WorkingFluids/Propane.mo             |   4 +-
 .../OrganicRankine/Data/WorkingFluids/R123.mo |   4 +-
 .../Data/WorkingFluids/R134a.mo               |   4 +-
 .../Data/WorkingFluids/R245fa.mo              |   4 +-
 .../OrganicRankine/Data/WorkingFluids/R32.mo  |   4 +-
 .../Data/WorkingFluids/Toluene.mo             |   4 +-
 .../OrganicRankine/Examples/ORCHotWater.mo    |  16 +-
 .../Validation/VariableSource.mo              |   2 +-
 .../Fluid/CHPs/OrganicRankine/package.order   |   1 +
 .../Python-Sources/MakeORCFluidRecord.py      | 110 ++++
 20 files changed, 700 insertions(+), 37 deletions(-)
 create mode 100644 Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
 create mode 100644 Buildings/Resources/Python-Sources/MakeORCFluidRecord.py

diff --git a/Buildings/.copiedFiles.txt b/Buildings/.copiedFiles.txt
index 7bb00d56c54..efd53538b55 100644
--- a/Buildings/.copiedFiles.txt
+++ b/Buildings/.copiedFiles.txt
@@ -850,6 +850,40 @@ Buildings/Fluid/BaseClasses/Validation/package.mo
 Buildings/Fluid/BaseClasses/Validation/package.order
 Buildings/Fluid/BaseClasses/package.mo
 Buildings/Fluid/BaseClasses/package.order
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/InterpolateStates.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/DryFluid.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/package.order
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/package.order
+Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/Generic.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Acetone.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Ethanol.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Heptane.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Pentane.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Propane.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R123.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R134a.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R245fa.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R32.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Toluene.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/package.order
+Buildings/Fluid/CHPs/OrganicRankine/Data/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/Data/package.order
+Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
+Buildings/Fluid/CHPs/OrganicRankine/Examples/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/Examples/package.order
+Buildings/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mo
+Buildings/Fluid/CHPs/OrganicRankine/Validation/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/Validation/package.order
+Buildings/Fluid/CHPs/OrganicRankine/package.mo
+Buildings/Fluid/CHPs/OrganicRankine/package.order
+Buildings/Fluid/CHPs/package.mo
+Buildings/Fluid/CHPs/package.order
 Buildings/Fluid/Chillers/BaseClasses/Carnot.mo
 Buildings/Fluid/Chillers/BaseClasses/PartialCarnot_T.mo
 Buildings/Fluid/Chillers/BaseClasses/PartialCarnot_y.mo
@@ -2295,6 +2329,15 @@ Buildings/Resources/Images/Fluid/Actuators/valvePressureDropSeries.png
 Buildings/Resources/Images/Fluid/Actuators/valveResponse.png
 Buildings/Resources/Images/Fluid/Actuators/valveResponse.svg
 Buildings/Resources/Images/Fluid/Actuators/valveSchematic.png
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/ComputationPaths.pdf
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/ComputationPaths.png
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/ComputationPaths.svg
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/CycleArchitecture.pdf
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/CycleArchitecture.png
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/CycleArchitecture.svg
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/SupportCurves.pdf
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/SupportCurves.png
+Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/SupportCurves.svg
 Buildings/Resources/Images/Fluid/FMI/ExportContainers/Validation/RoomConvectiveHVACConvective.pdf
 Buildings/Resources/Images/Fluid/FMI/ExportContainers/Validation/RoomConvectiveHVACConvective.png
 Buildings/Resources/Images/Fluid/FMI/ExportContainers/Validation/RoomConvectiveHVACConvective.svg
@@ -2424,6 +2467,7 @@ Buildings/Resources/Images/Utilities/Math/Functions/Examples/cubicHermite.png
 Buildings/Resources/Images/Utilities/Math/Functions/SmoothExponentialXPower.png
 Buildings/Resources/Images/Utilities/Math/int.pdf
 Buildings/Resources/Images/Utilities/Math/int.png
+Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
 Buildings/Resources/Scripts/Dymola/Airflow/Multizone/BaseClasses/Examples/PowerLaw.mos
 Buildings/Resources/Scripts/Dymola/Airflow/Multizone/BaseClasses/Examples/PowerLawFixedM.mos
 Buildings/Resources/Scripts/Dymola/Airflow/Multizone/BaseClasses/Examples/WindPressureLowRise.mos
@@ -2645,6 +2689,10 @@ Buildings/Resources/Scripts/Dymola/Fluid/BaseClasses/FlowModels/Validation/Inver
 Buildings/Resources/Scripts/Dymola/Fluid/BaseClasses/FlowModels/Validation/InvertingBasicFlowFunction_m_flow.mos
 Buildings/Resources/Scripts/Dymola/Fluid/BaseClasses/Validation/ActuatorFilter.mos
 Buildings/Resources/Scripts/Dymola/Fluid/BaseClasses/Validation/MassFlowRateMultiplier.mos
+Buildings/Resources/Scripts/Dymola/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/DryFluid.mos
+Buildings/Resources/Scripts/Dymola/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mos
+Buildings/Resources/Scripts/Dymola/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mos
+Buildings/Resources/Scripts/Dymola/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mos
 Buildings/Resources/Scripts/Dymola/Fluid/Chillers/Examples/Carnot_TEva.mos
 Buildings/Resources/Scripts/Dymola/Fluid/Chillers/Examples/Carnot_y.mos
 Buildings/Resources/Scripts/Dymola/Fluid/Chillers/ModularReversible/Examples/CarnotWithLosses.mos
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
index da4709af2e9..4452b1cdb32 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
@@ -190,8 +190,8 @@ This model computes the pinch points and the energy exchange,
 and interfaces with the input and output variables.
 The evaporating temperature is fixed as a parameter.
 See the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 for more details.
 </html>", revisions="<html>
 <ul>
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/InterpolateStates.mo b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/InterpolateStates.mo
index 18efb81172a..e140d3cd935 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/InterpolateStates.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/InterpolateStates.mo
@@ -307,8 +307,8 @@ protected
 <p>
 This model performs the property interpolations of a given working fluid.
 See the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 for more details.
 </html>", revisions="<html>
 <ul>
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mo b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mo
index de7bebcff9d..6826dbac7bd 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/Validation/WetFluid.mo
@@ -18,8 +18,8 @@ except that it validates the handling of wet working fluids.
 As a result, a superheating temperature is computed that ensures
 the expansion does not land under the dome.
 How this superheating temperature is found is explained in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>.
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>.
 </p>
 </html>",revisions="<html>
 <ul>
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo b/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
new file mode 100644
index 00000000000..3f44f3d5705
--- /dev/null
+++ b/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
@@ -0,0 +1,504 @@
+within Buildings.Fluid.CHPs.OrganicRankine;
+model ConstantEvaporation "Organic Rankine cycle as a bottoming cycle"
+
+  extends Buildings.Fluid.Interfaces.FourPortHeatMassExchanger(
+    final m1_flow_nominal = mHot_flow_nominal,
+    final dp1_nominal = dpHot_nominal,
+    final m2_flow_nominal = mCol_flow_nominal,
+    final dp2_nominal = dpCol_nominal,
+    energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
+    T1_start = max(pro.T)*2/3 + min(pro.T)*1/3,
+    T2_start = max(pro.T)*1/10 + min(pro.T)*9/10,
+    redeclare final Buildings.Fluid.MixingVolumes.MixingVolume vol2(
+      V=m2_flow_nominal*tau2/rho2_nominal,
+      nPorts=2,
+      final prescribedHeatFlowRate=true),
+    final vol1(
+      final prescribedHeatFlowRate=true));
+
+  replaceable parameter Buildings.Fluid.CHPs.OrganicRankine.Data.Generic pro
+    constrainedby Buildings.Fluid.CHPs.OrganicRankine.Data.Generic
+    "Property records of the working fluid"
+    annotation(choicesAllMatching = true,Dialog(group="Cycle"));
+  parameter Modelica.Units.SI.MassFlowRate mHot_flow_nominal
+    "Nominal mass flow rate of the evaporator fluid"
+    annotation(Dialog(group="Evaporator"));
+  parameter Modelica.Units.SI.PressureDifference dpHot_nominal(
+    displayUnit="Pa")
+    "Nominal pressure drop of the hot fluid in evaporator"
+    annotation(Dialog(group="Evaporator"));
+  parameter Modelica.Units.SI.TemperatureDifference dTPinEva_set(
+    final min = 0) = 5
+    "Set evaporator pinch point temperature difference"
+    annotation(Dialog(group="Evaporator"));
+  parameter Boolean useEvaporatingPressure = false
+    "Set true to specify working fluid evaporating pressure instead of temperature"
+    annotation(Dialog(group="Evaporator"));
+  parameter Modelica.Units.SI.ThermodynamicTemperature TWorEva =
+    max(pro.T)*2/3 + min(pro.T)*1/3
+    "Evaporating temperature of the working fluid"
+    annotation(Dialog(group="Evaporator", enable = not useEvaporatingPressure));
+  parameter Modelica.Units.SI.Pressure pWorEva(displayUnit="kPa") =
+    max(pro.p)*2/3 + min(pro.p)*1/3
+    "Evaporating pressure of the working fluid"
+    annotation(Dialog(group="Evaporator", enable = useEvaporatingPressure));
+  parameter Modelica.Units.SI.MassFlowRate mCol_flow_nominal
+    "Nominal mass flow rate of the condenser fluid"
+    annotation(Dialog(group="Condenser"));
+  parameter Modelica.Units.SI.PressureDifference dpCol_nominal(
+    displayUnit="Pa")
+    "Nominal pressure drop of the cold fluid in condenser"
+    annotation(Dialog(group="Condenser"));
+  parameter Modelica.Units.SI.TemperatureDifference dTPinCon(
+    final min = 0) = 10
+    "Condenser pinch point temperature difference"
+    annotation(Dialog(group="Condenser"));
+  parameter Boolean useLowCondenserPressureWarning = true
+    "If true, issues warning if pCon < 101325 Pa"
+    annotation(Dialog(group="Condenser"));
+  parameter Modelica.Units.SI.MassFlowRate mWor_flow_max(
+    final min = 0)
+    "Upper bound of working fluid flow rate"
+    annotation(Dialog(group="Cycle"));
+  parameter Modelica.Units.SI.MassFlowRate mWor_flow_min(
+    final min = 0)
+    "Lower bound of working fluid flow rate"
+    annotation(Dialog(group="Cycle"));
+  parameter Modelica.Units.SI.MassFlowRate mWor_flow_hysteresis
+    = mWor_flow_min + (mWor_flow_max - mWor_flow_min) * 0.1
+    "Hysteresis for turning off the cycle when flow too low"
+    annotation(Dialog(group="Cycle"));
+  parameter Modelica.Units.SI.Efficiency etaExp
+    "Expander efficiency"
+    annotation(Dialog(group="Cycle"));
+  parameter Modelica.Units.SI.Efficiency etaPum
+    "Pump efficiency"
+    annotation(Dialog(group="Cycle"));
+
+  Modelica.Blocks.Interfaces.BooleanInput ena
+    "Enable cycle; set false to force working fluid flow to zero" annotation (
+      Placement(transformation(extent={{-140,-20},{-100,20}}),
+        iconTransformation(extent={{-120,-10},{-100,10}})));
+
+  Modelica.Blocks.Interfaces.RealOutput PExp(
+    final quantity="Power",
+    final unit="W") "Expander power generation"
+    annotation (Placement(
+        transformation(extent={{100,10},{140,50}}), iconTransformation(extent={{100,20},
+            {120,40}})));
+  Modelica.Blocks.Interfaces.RealOutput QEva_flow(
+    final quantity="HeatFlowRate",
+    final unit="W") "Evaporator heat flow rate into the cycle" annotation (
+      Placement(transformation(extent={{100,70},{140,110}}),iconTransformation(
+          extent={{-10,-10},{10,10}},
+        rotation=0,
+        origin={110,90})));
+  Modelica.Blocks.Interfaces.RealOutput QCon_flow(
+    final quantity="HeatFlowRate",
+    final unit="W") "Condenser heat flow rate out of the cycle" annotation (
+      Placement(transformation(extent={{100,-110},{140,-70}}),
+        iconTransformation(extent={{-10,-10},{10,10}},
+        rotation=0,
+        origin={110,-90})));
+  Modelica.Blocks.Interfaces.BooleanOutput on_actual
+    "Actual on off status of the cycle" annotation (Placement(transformation(
+          extent={{100,-20},{140,20}}), iconTransformation(extent={{100,-10},{
+            120,10}})));
+  Modelica.Blocks.Interfaces.RealOutput PPum(
+    final quantity="Power",
+    final unit="W")
+    "Electrical power consumption of the pump" annotation (Placement(
+        transformation(extent={{100,-50},{140,-10}}),iconTransformation(extent={{100,-40},
+            {120,-20}})));
+
+  Buildings.Fluid.CHPs.OrganicRankine.BaseClasses.FixedEvaporating cyc(
+    final pro=pro,
+    final mWor_flow_max=mWor_flow_max,
+    final mWor_flow_min=mWor_flow_min,
+    final mWor_flow_hysteresis=mWor_flow_hysteresis,
+    final TWorEva =
+            if useEvaporatingPressure
+            then Buildings.Utilities.Math.Functions.smoothInterpolation(
+                   x = pWorEva,
+                   xSup = pro.p,
+                   ySup = pro.T)
+            else TWorEva,
+    final dTPinEva_set=dTPinEva_set,
+    final dTPinCon=dTPinCon,
+    final cpHot=Medium1.specificHeatCapacityCp(sta1_nominal),
+    final cpCol=Medium2.specificHeatCapacityCp(sta2_nominal),
+    final etaExp=etaExp,
+    final etaPum=etaPum,
+    final useLowCondenserPressureWarning=useLowCondenserPressureWarning)
+    "Thermodynamic computations of the organic Rankine cycle"
+    annotation (Placement(transformation(extent={{-10,-10},{10,10}})));
+
+protected
+  Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow preHeaFloEva
+    "Prescribed heat flow rate"
+    annotation (Placement(transformation(extent={{39,30},{19,50}})));
+  Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow preHeaFloCon
+    "Prescribed heat flow rate"
+    annotation (Placement(transformation(extent={{41,-70},{21,-50}})));
+  Modelica.Blocks.Sources.RealExpression expTHotIn(y=Medium1.temperature(
+        state=Medium1.setState_phX(
+          p=port_a1.p,
+          h=inStream(port_a1.h_outflow),
+          X=inStream(port_a1.Xi_outflow))))
+    "Expression for evaporator hot fluid incoming temperature"
+    annotation (Placement(transformation(extent={{-60,20},{-40,40}})));
+  Modelica.Blocks.Sources.RealExpression expMHot_flow(y=m1_flow)
+    "Expression for evaporator hot fluid flow rate"
+    annotation (Placement(transformation(extent={{-60,0},{-40,20}})));
+  Modelica.Blocks.Sources.RealExpression expTColIn(y=Medium2.temperature(
+        state=Medium2.setState_phX(
+          p=port_a2.p,
+          h=inStream(port_a2.h_outflow),
+          X=inStream(port_a2.Xi_outflow))))
+    "Expression for condenser cold fluid incoming temperature"
+    annotation (Placement(transformation(extent={{-60,-20},{-40,0}})));
+  Modelica.Blocks.Sources.RealExpression expMCol_flow(y=m2_flow)
+    "Expression for condenser cold fluid flow rate"
+    annotation (Placement(transformation(extent={{-60,-40},{-40,-20}})));
+equation
+  connect(preHeaFloEva.port, vol1.heatPort) annotation (Line(points={{19,40},{-16,
+          40},{-16,60},{-10,60}}, color={191,0,0}));
+  connect(preHeaFloCon.port, vol2.heatPort) annotation (Line(points={{21,-60},{12,
+          -60}},                      color={191,0,0}));
+  connect(expTHotIn.y, cyc.THotIn) annotation (Line(points={{-39,30},{-20,30},{-20,
+          8},{-11,8}},     color={0,0,127}));
+  connect(expMHot_flow.y, cyc.mHot_flow) annotation (Line(points={{-39,10},{-30,
+          10},{-30,4},{-11,4}}, color={0,0,127}));
+  connect(expTColIn.y, cyc.TColIn) annotation (Line(points={{-39,-10},{-30,-10},
+          {-30,-4},{-11,-4}}, color={0,0,127}));
+  connect(expMCol_flow.y, cyc.mCol_flow) annotation (Line(points={{-39,-30},{-20,
+          -30},{-20,-8},{-11,-8}}, color={0,0,127}));
+  connect(cyc.PExp,PExp)  annotation (Line(points={{11,4},{84,4},{84,30},{120,30}},
+        color={0,0,127}));
+  connect(ena, cyc.ena)
+    annotation (Line(points={{-120,0},{-11,0}}, color={255,0,255}));
+  connect(cyc.QEva_flow, QEva_flow) annotation (Line(points={{11,8},{80,8},{80,90},
+          {120,90}},     color={0,0,127}));
+  connect(cyc.QCon_flow, QCon_flow) annotation (Line(points={{11,-8},{80,-8},{
+          80,-70},{96,-70},{96,-90},{120,-90}},
+                              color={0,0,127}));
+  connect(cyc.on_actual, on_actual) annotation (Line(points={{11,0},{120,0}},
+                           color={255,0,255}));
+  connect(cyc.PPum, PPum) annotation (Line(points={{11,-4},{84,-4},{84,-30},{120,
+          -30}}, color={0,0,127}));
+  connect(cyc.QEva_flow, preHeaFloEva.Q_flow)
+    annotation (Line(points={{11,8},{80,8},{80,40},{39,40}}, color={0,0,127}));
+  connect(cyc.QCon_flow, preHeaFloCon.Q_flow) annotation (Line(points={{11,-8},
+          {80,-8},{80,-60},{41,-60}}, color={0,0,127}));
+  annotation (defaultComponentName = "orc",
+  Icon(coordinateSystem(preserveAspectRatio=false), graphics={
+        Line(
+          points={{-60,-60},{-28,-20},{16,32},{40,60},{52,60},{54,30},{48,2},{
+              52,-38},{58,-58}},
+          color={255,255,255},
+          smooth=Smooth.Bezier,
+          thickness=0.5),
+        Line(
+          points={{6,20},{52,20},{66,-6},{50,-18},{-26,-18}},
+          color={255,255,255},
+          thickness=0.5,
+          pattern=LinePattern.Dash)}),               Diagram(
+        coordinateSystem(preserveAspectRatio=false)),
+Documentation(info="<html>
+<p>
+Model of an organic Rankine cycle (ORC) as a bottoming cycle.
+</p>
+<p>
+The thermodynamic cycle is steady-state while the evaporator and the condenser
+can be configured to have first order dynamics.
+The fluid stream 1 (using <code>Medium1</code>, <code>port_a1</code>, etc.)
+is the evaporator hot fluid, e.g., waste heat,
+and the stream 2 is the condenser cold fluid.
+The working fluid of the cycle is not based on a typical Modelica medium model.
+See the Thermodynamic Properties section of this document for the rational.
+</p>
+<h4>Cycle Architecture and Governing Equations</h4>
+<p>
+The implemented ORC is modeled based on the simplified cycle shown in the figure below.
+The cycle has two variants depending on the shape of the saturation lines of
+the working fluid and <i>&eta;<sub>exp</sub></i>.
+For any given working fluid, the cycle is fully determined by providing
+the working fluid evaporating temperature <i>T<sub>w,eva</sub></i>,
+the working fluid condensing temperature <i>T<sub>w,con</sub></i>,
+the expander efficiency <i>&eta;<sub>exp</sub></i>, and
+the pump efficiency <i>&eta;<sub>pum</sub></i>.
+The superheating temperature difference <i>&Delta;T<sub>sup</sub></i>
+is minimized, meaning it is zero whenever possible; otherwise it assumes
+the smallest value not to cause the expander outlet state to fall
+under the two-phase region, i.e. the \"dome\".
+Subcooling after the condenser is not considered.
+The Thermodynamic Properties section of this document details how these
+state points are found.
+</p>
+<p>
+An important assumption is that all heat is dissipated, i.e.,
+the cycle is not controlled by thermal load.
+</p>
+<p align=\"center\">
+<img src=\"modelica://Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/CycleArchitecture.png\"
+alt=\"CycleArchitecture\" width=\"800\" height=\"300\"/></p>
+<p>
+The cycle processes the heat at a fixed
+<i>T<sub>w,eva</sub></i> provided by the user.
+The evaporator heat exchange is governed by
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+Q&#775;<sub>eva</sub> = m&#775;<sub>h</sub>&nbsp;c<sub>p,h</sub>&nbsp;(T<sub>h,out</sub> - T<sub>h,in</sub>),<br/>
+Q&#775;<sub>eva</sub> = m&#775;<sub>w</sub>&nbsp;(h<sub>pum,out</sub> - h<sub>exp,in</sub>),
+</p>
+<p>
+where the subscripts are
+<i>eva</i> for evaporator,
+<i>exp</i> for expander,
+<i>h</i> for hot fluid of the evaporator, i.e. the fluid carrying heat,
+<i>pum</i> for pump, and
+<i>w</i> for working fluid.
+</p>
+<p>
+The cycle accommodates the variable flow rate and temperature
+of the waste heat stream by changing the working fluid mass flow rate <i>m&#775;<sub>w</sub></i>
+to maintain a constant pinch point (PP) temperature difference
+at the evaporator <i>&Delta;T<sub>pin,eva</sub></i>.
+This difference is found from
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+(T<sub>pin,eva</sub> - T<sub>h,out</sub>)&nbsp;(h<sub>exp,in</sub> - h<sub>pum,out</sub>)
+= (T<sub>h,in</sub> - T<sub>h,out</sub>)&nbsp;(h<sub>eva,pin</sub> - h<sub>pum,out</sub>),<br/>
+&Delta;T<sub>pin,eva</sub> = T<sub>pin,eva</sub> - T<sub>w,eva</sub>.
+</p>
+<p>
+The condenser side uses the same equations with the evaporator variables
+replaced by their condenser counterparts where appropriate. Hence,
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+Q&#775;<sub>con</sub> = m&#775;<sub>c</sub>&nbsp;c<sub>p,c</sub>&nbsp;(T<sub>c,out</sub> - T<sub>c,in</sub>),<br/>
+Q&#775;<sub>con</sub> = m&#775;<sub>w</sub>&nbsp;(h<sub>pum,in</sub> - h<sub>exp,out</sub>),<br/>
+(T<sub>c,pin</sub> - T<sub>c,in</sub>)&nbsp;(h<sub>exp,out</sub> - h<sub>pum,in</sub>)
+= (T<sub>c,out</sub> - T<sub>c,in</sub>)&nbsp;(h<sub>con,pin</sub> - h<sub>pum,in</sub>),<br/>
+&Delta;T<sub>con,pin</sub> = T<sub>w,con</sub> - T<sub>c,pin</sub>,
+</p>
+<p>
+where the subscripts are
+<i>con</i> for condenser, and
+<i>c</i> for cold fluid in the condenser.<br/>
+</p>
+<p>
+The electric power output of the expander is
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+P<sub>exp</sub> = m&#775;<sub>w</sub>&nbsp;(h<sub>exp,in</sub> - h<sub>exp,out</sub>).
+</p>
+<p>
+The electric power consumption of the pump is
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+P<sub>pum</sub> = m&#775;<sub>w</sub>&nbsp;(h<sub>pum,out</sub> - h<sub>pum,in</sub>).
+</p>
+<p>
+The pump work is
+</p>
+<p align=\"center\" style=\"font-style:italic;\">
+P<sub>pum</sub> = m&#775;<sub>w</sub>&nbsp;
+(p<sub>eva</sub> - p<sub>con</sub>) / (&rho;<sub>pum,in</sub>&nbsp;&eta;<sub>pum</sub>).
+</p>
+<p>
+This takes advantage of the negligible density change of the liquid
+to avoid a property search in the subcooled liquid region.
+</p>
+<p>
+In summary, the model has the following information flow:
+</p>
+<table summary=\"summary\" border=\"1\" cellspacing=\"0\" cellpadding=\"2\" style=\"border-collapse:collapse;\">
+<tr>
+<th>User-specified parameters</th>
+<th>Inputs</th>
+<th>Outputs</th>
+</tr>
+<tr>
+<td>
+<i>T<sub>w,eva</sub></i> - Working fluid evaporating temperature,<br/>
+<i>&Delta;T<sub>pin,eva</sub></i> - Evaporator pinch point temperature difference,<br/>
+<i>&Delta;T<sub>pin,con</sub></i> - Condenser pinch point temperature difference,<br/>
+<i>&eta;<sub>exp</sub></i> - Expander efficiency,<br/>
+<i>&eta;<sub>pum</sub></i> - Pump efficiency.
+</td>
+<td>
+<i>T<sub>h,in</sub></i> - Evaporator hot fluid incoming temperature,<br/>
+<i>m&#775;<sub>h</sub></i> - Evaporator hot fluid flow rate,<br/>
+<i>T<sub>c,in</sub></i> - Condenser cold fluid incoming temperature,<br/>
+<i>m&#775;<sub>c</sub></i> - Condenser cold fluid flow rate.
+</td>
+<td>
+<i>m&#775;<sub>w</sub></i> - Working fluid flow rate,<br/>
+<i>T<sub>w,con</sub></i> - Working fluid condensing temperature,<br/>
+<i>T<sub>h,out</sub></i> - Evaporator hot fluid outgoing temperature,<br/>
+<i>T<sub>c,out</sub></i> - Condenser cold fluid outgoing temperature,<br/>
+<i>Q&#775;<sub>eva</sub></i> - Evaporator heat flow rate,<br/>
+<i>Q&#775;<sub>con</sub></i> - Condenser heat flow rate,<br/>
+<i>P<sub>exp</sub></i> - Expander power output,<br/>
+<i>P<sub>pum</sub></i> - Pump power consumption.
+</td>
+</tr>
+</table>
+<h4>Constraints</h4>
+<p>
+The ORC system controls <i>m&#775;<sub>w</sub></i> to maintain the prescribed
+evaporator PP temperature difference set point.
+Although the model does not implement this as a control loop,
+an upper limit and a lower limit are imposed on
+<i>m&#775;<sub>w</sub></i> to reflect the capacity constraints of a sized cycle.
+</p>
+<ul>
+<li>
+The working fluid mass flow rate <i>m&#775;<sub>w</sub></i> will not go higher than a prescribed
+upper limit. Rather, <i>m&#775;<sub>w</sub></i> stays at the
+user-specified upper limit and <i>&Delta;T<sub>pin,eva</sub></i>
+increases beyond its set point.
+This may happen when the incoming hot fluid has a
+high flow rate or a high incoming temperature, i.e., it
+carries more energy than the cycle is sized to process.
+</li>
+<li>
+When the working fluid mass flow rate <i>m&#775;<sub>w</sub></i> needs to go below a prescribed lower limit,
+<i>m&#775;<sub>w</sub></i> is set to zero and the cycle is switched off. This
+may happen when the incoming waste heat fluid has
+a low flow rate or a low incoming temperature, i.e., it
+carries too little energy.
+</li>
+</ul>
+<p>
+How these constraints affect the cycle's behavior reacting to
+a variable waste heat fluid stream is demonstrated in
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Validation.VariableSource\">
+Buildings.Fluid.CHPs.OrganicRankine.Validation.VariableSource</a>.
+</p>
+<h4>Thermodynamic Properties</h4>
+<p>
+The thermodynamic properties of the working fluid are not computed by a typical
+Modelica medium model, but by interpolating data records in
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Data\">
+Buildings.Fluid.CHPs.OrganicRankine.Data</a>.
+Specific enthalpy and specific entropy values are provided as support points
+on the saturated liquid line, the saturated vapor line, and
+a superheated vapor line (called the reference line).
+The values of these support points were obtained using CoolProp
+(<a href=\"https://www.coolprop.org\">https://www.coolprop.org</a>;
+Bell et al., 2014) through its Python wrapper and stored as Modelica records.
+An example Python file is provided in
+<code>Buildings/Resources/Python-Sources/MakeORCFluidRecord.py</code>,
+but note that this file is not maintained.
+The records included in this library have ten data points for each line.
+It is recommended to have at least four points to take full advantage of
+the cubit Hermite spline interpolation that is set up in this model.
+</p>
+<p>
+Thermodynamic state points in the cycle are determined by various schemes
+of interpolation and extrapolation.
+</p>
+<p align=\"center\">
+<img src=\"modelica://Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/SupportCurves.png\"
+alt=\"SupportCurves\" width=\"400\" height=\"300\"/></p>
+<ul>
+<li>
+On the saturation line, the specific enthalpy, specific
+entropy or density, here labeled as <i>y<sub>A</sub></i>, are obtained
+using cubic Hermite spline interpolation as
+<p align=\"center\" style=\"font-style:italic;\">
+y<sub>A</sub> = s(u<sub>A</sub>,d)
+</p>
+where <i>s(&middot;,&middot;)</i> is a cubic Hermite spline,
+<i>u<sub>A</sub></i> is the input property, and
+<i>d</i> are the support points.
+For the saturation curves, the user can configure the model
+to use either the saturation pressure or the saturation
+temperature for <i>u<sub>A</sub></i>.
+For the reference line <i>u<sub>A</sub></i> is the pressure.
+</li>
+<li>
+If the fluid is wet, the isentropic expander outlet point is in between
+the saturation lines. In this case, its enthalpy <i>h<sub>B</sub></i>
+is obtained from
+<p align=\"center\" style=\"font-style:italic;\">
+(h<sub>B</sub> - h<sub>1</sub>) / (s<sub>B</sub> - s<sub>1</sub>)
+= (h<sub>2</sub> - h<sub>1</sub>) / (s<sub>2</sub> - s<sub>1</sub>)
+</p>
+where <i>s<sub>B</sub></i> is known because it equals the expander inlet
+entropy, and all other points are on the saturation
+line and therefore can be found as point <i>A</i>.
+</li>
+<li>
+<i>C</i> is a point in the superheated vapor region. This is the case for
+the expander inlet or outlet depending on the shape of the cycle.
+The isobaric lines are not straight in this section, but they are
+assumed linear so that the method for <i>B</i> can be applied using the
+saturated vapor line and the reference line, albeit with less accuracy.
+</li>
+</ul>
+<p>
+The cycle can be completely defined by providing the following quantities:
+evaporating temperature <i>T<sub>eva</sub></i> or pressure <i>p<sub>eva</sub></i>,
+condensing temperature <i>T<sub>con</sub></i> or pressure <i>p<sub>con</sub></i>,
+expander efficiency <i>&eta;<sub>exp</sub></i>, and
+pump efficiency <i>&eta;<sub>pum</sub></i>.
+Most of the important state points can be found via the interpolation schemes
+described above. The only exceptions are the expander inlet, expander outlet,
+and the pump outlet.
+</p>
+<p align=\"center\">
+<img src=\"modelica://Buildings/Resources/Images/Fluid/CHPs/OrganicRankine/ComputationPaths.png\"
+alt=\"ComputationPaths\" width=\"1200\" height=\"300\"/></p>
+<ul>
+<li>
+A dry cycle is a cycle where the expansion starts from
+the saturated vapor line and ends in the superheated vapor region.
+For either a dry fluid (a) or a wet fluid (b) undergoing such a cycle,
+<p align=\"center\" style=\"font-style:italic;\">
+h<sub>exp,out</sub> - h<sub>exp,in</sub>
+= (h<sub>exp,out,ise</sub> - h<sub>exp,in</sub>) &eta;<sub>exp</sub>
+</p>
+where <i>h<sub>exp,out</sub></i> is solved and <i>h<sub>exp,in</sub></i> is known.
+</li>
+<li>
+A wet cycle is a cycle where the expansion starts from
+the superheated vapor region and ends on the saturated vapor line.
+In this scenario,
+<p align=\"center\" style=\"font-style:italic;\">
+h<sub>exp,out</sub> - h<sub>exp,in</sub>
+= (h<sub>exp,out</sub> - h<sub>exp,inl,ise</sub>) &eta;<sub>exp</sub>
+</p>
+where <i>h<sub>exp,out</sub></i> is known and <i>h<sub>exp,in</sub></i> is solved.
+For this fluid and this <i>&eta;<sub>exp</sub></i>,
+if the expansion started from the saturated vapor line,
+the outlet point would end up under the dome.
+</li>
+</ul>
+<h4>Implementation</h4>
+The user can parameterise the evaporating condition by providing either the
+evaporating temperature <code>TWorEva</code> or the evaporating pressure
+<code>pWorEva</code>. To support this, a default parameter assignment is
+provided to both. Otherwise there would be unassigned parameters even though
+they are not needed.
+<h4>References</h4>
+<p>
+Bell IH, Wronski J, Quoilin S, Lemort V.
+Pure and pseudo-pure fluid thermophysical property evaluation and the open-source thermophysical property library CoolProp.
+<i>Industrial &amp; engineering chemistry research.
+</i>
+2014 Feb 12;53(6):2498-508.
+<a href=\"https://doi.org/10.1021/ie4033999\">https://doi.org/10.1021/ie4033999</a>
+</p>
+</html>", revisions="<html>
+<ul>
+<li>
+January 29, 2024, by Hongxiang Fu:<br/>
+First implementation. This is for
+<a href=\"https://github.com/lbl-srg/modelica-buildings/issues/3433\">#3433</a>.
+</li>
+</ul>
+</html>"));
+end ConstantEvaporation;
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/Generic.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/Generic.mo
index 0fbe79019fc..b99bc827090 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/Generic.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/Generic.mo
@@ -32,8 +32,8 @@ annotation (
 <p>
 Record containing parameters for working fluid properties.
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Acetone.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Acetone.mo
index 6321a7d7970..41f281cb2cf 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Acetone.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Acetone.mo
@@ -50,8 +50,8 @@ record Acetone "Data record for acetone"
 Record containing properties of acetone.
 Its name in CoolProp is \"Acetone\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Ethanol.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Ethanol.mo
index f85f5b7c3c9..e7b64884899 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Ethanol.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Ethanol.mo
@@ -48,8 +48,8 @@ record Ethanol "Data record for ethanol"
 Record containing properties of ethanol.
 Its name in CoolProp is \"Ethanol\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Heptane.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Heptane.mo
index f6f795d0395..0294bf8fdc4 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Heptane.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Heptane.mo
@@ -49,8 +49,8 @@ record Heptane "Data record for n-heptane"
 Record containing properties of n-heptane.
 Its name in CoolProp is \"n-Heptane\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Pentane.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Pentane.mo
index c1107fe5b1b..1a7e6eecdc6 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Pentane.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Pentane.mo
@@ -50,8 +50,8 @@ record Pentane "Data record for n-pentane (R601)"
 Record containing properties of n-pentane (R601).
 Its name in CoolProp is \"n-Pentane\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Propane.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Propane.mo
index 0ad16978df8..619f1414ed2 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Propane.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Propane.mo
@@ -50,8 +50,8 @@ record Propane "Data record for propane (R290)"
 Record containing properties of propane (R290).
 Its name in CoolProp is \"Propane\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R123.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R123.mo
index d4045ad6dd6..e42c563ec51 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R123.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R123.mo
@@ -49,8 +49,8 @@ record R123 "Data record for R123"
 Record containing properties of R123.
 Its name in CoolProp is \"R123\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R134a.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R134a.mo
index 863de4c0a9a..5111ba21952 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R134a.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R134a.mo
@@ -50,8 +50,8 @@ record R134a "Data record for R134a"
 Record containing properties of R134a.
 Its name in CoolProp is \"R134a\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R245fa.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R245fa.mo
index 1202e04272d..cf66e66e44d 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R245fa.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R245fa.mo
@@ -50,8 +50,8 @@ record R245fa "Data record for R245fa"
 Record containing properties of R245fa.
 Its name in CoolProp is \"R245fa\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R32.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R32.mo
index 4304ab99a3a..75bbdb30c18 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R32.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/R32.mo
@@ -50,8 +50,8 @@ record R32 "Data record for R32"
 Record containing properties of R32.
 Its name in CoolProp is \"R32\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Toluene.mo b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Toluene.mo
index c81115d8ed5..790d459f385 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Toluene.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Data/WorkingFluids/Toluene.mo
@@ -48,8 +48,8 @@ record Toluene "Data record for toluene"
 Record containing properties of toluene.
 Its name in CoolProp is \"Toluene\".
 A figure in the documentation of
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 shows which lines these arrays represent.
 </p>
 </html>"));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
index b91638c6fde..4fa8fbcb6f2 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
@@ -18,7 +18,7 @@ model ORCHotWater "ORC that outputs hot water at a fixed temperature"
   parameter Modelica.Units.SI.ThermodynamicTemperature TCol_start = 35 + 273.15
     "Start value for cold fluid temperature";
 
-  Buildings.Fluid.CHPs.OrganicRankine.Cycle orc(
+  Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation orc(
     redeclare final package Medium1 = MediumHot,
     redeclare final package Medium2 = MediumCol,
     T2_start=TCol_start,
@@ -95,11 +95,11 @@ model ORCHotWater "ORC that outputs hot water at a fixed temperature"
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
     T_start=TCol_start,
     from_dp=false,
-    use_strokeTime=false,
+    use_inputFilter=false,
     final m_flow_nominal=mCol_flow_nominal,
     final dpValve_nominal=dpValCol_nominal,
-    final dpFixed_nominal=fill(dpCon_nominal, 2)) "Control valve" annotation (
-      Placement(transformation(
+    final dpFixed_nominal=fill(dpCon_nominal, 2)) "Control valve"
+    annotation (Placement(transformation(
         extent={{-10,10},{10,-10}},
         rotation=180,
         origin={40,-40})));
@@ -123,11 +123,11 @@ model ORCHotWater "ORC that outputs hot water at a fixed temperature"
         extent={{10,-10},{-10,10}},
         rotation=180,
         origin={40,-80})));
-  Buildings.Controls.OBC.CDL.Conversions.BooleanToReal booToRea(
+  Modelica.Blocks.Math.BooleanToReal booToRea(
     realTrue = mCol_flow_nominal)
     "Constant speed primary pump control signal"
     annotation (Placement(transformation(extent={{-140,0},{-120,20}})));
-  Buildings.Controls.OBC.CDL.Reals.Hysteresis hys(
+  Modelica.Blocks.Logical.Hysteresis hys(
     uLow=mCol_flow_nominal/3,
     uHigh=mCol_flow_nominal/2) "Hysteresis"
     annotation (Placement(transformation(extent={{-180,40},{-160,60}})));
@@ -204,8 +204,8 @@ annotation(experiment(StopTime=900,Tolerance=1E-6),
   Documentation(info="<html>
 <p>
 This example model demonstrates how
-<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.Cycle\">
-Buildings.Fluid.CHPs.OrganicRankine.Cycle</a>
+<a href=\"Modelica://Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation\">
+Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>
 can be integrated in a system.
 The three-way valve is controlled to track the hot water
 output temperature, which is the cold fluid of the ORC,
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mo b/Buildings/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mo
index 9de99ad7b1f..6e744762ed6 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Validation/VariableSource.mo
@@ -14,7 +14,7 @@ model VariableSource
   parameter Modelica.Units.SI.MassFlowRate mCol_flow_nominal = 1
     "Nominal mass flow rate of condenser cold fluid";
 
-  Buildings.Fluid.CHPs.OrganicRankine.Cycle orc(
+  Buildings.Fluid.CHPs.OrganicRankine.ConstantEvaporation orc(
     redeclare package Medium1 = MediumHot,
     redeclare package Medium2 = MediumCol,
     pro=pro,
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/package.order b/Buildings/Fluid/CHPs/OrganicRankine/package.order
index 53a856d00e8..330e20c2f03 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/package.order
+++ b/Buildings/Fluid/CHPs/OrganicRankine/package.order
@@ -1,3 +1,4 @@
+ConstantEvaporation
 Cycle
 Data
 Examples
diff --git a/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py b/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
new file mode 100644
index 00000000000..3ccf30ba8ad
--- /dev/null
+++ b/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Example python code used to generate working fluid records for
+Fluid.CHPs.OrganicRankine.Data.
+Note that this script is not maintained.
+
+This file was created at:
+    Python 3.11.9
+    Ubuntu 20.04.3
+    CoolProp 6.6.0
+    Modelica IBPSA Library 6612f5a
+    Modelica Buildings Library c34c05a
+"""
+
+import CoolProp.CoolProp as CP
+
+import numpy as np
+import os
+
+WITHIN = "IBPSA." # e.g. "IBPSA." or "Buildings."
+FLUIDNAME = {"coolprop" : "n-Pentane",
+             "modelica" : "Pentane",
+             "description" : "n-pentane (R601)"}
+""" To find a fluid name in CoolProp,
+        ```
+        import CoolProp
+        print(CoolProp.__fluids__)
+        ```
+    The Modelica name will be used as the class name, so make sure it is legal.
+    The description name is whatever you want it to appear
+        in descriptions and documentations.
+"""
+dTRef = 30
+    # Temperature difference from the reference line to the saturated vapour line
+dirOutput = os.path.dirname(os.path.realpath(__file__))
+
+def ModelicaArray(arr):
+       s = "{\n" + " "*9 \
+           + np.array2string(arr,
+                             max_line_width=75,
+                             precision=9,
+                             separator=",",
+                             prefix=" "*8).replace("[","").replace("]","") \
+           + "}"
+       return s
+
+def WriteOneFile(fluid, dTRef = 30):
+       nCP = fluid["coolprop"]
+       nMO = fluid["modelica"]
+       nDS = fluid["description"]
+       
+       TCri = CP.PropsSI(nCP, 'Tcrit')
+
+       TMax = TCri -10
+       TMin = 273.15 - 10
+
+       T = np.linspace(TMin,TMax,10)
+       p = CP.PropsSI('P','T',T,'Q',1,nCP)
+       rhoLiq = CP.PropsSI('D','T',T,'Q',0,nCP)
+       pMin = CP.PropsSI('P','T',TMin,'Q',1,nCP)
+       pMax = CP.PropsSI('P','T',TMax,'Q',1,nCP)
+       
+       sSatLiq = CP.PropsSI('S','T',T,'Q',0,nCP) # Entropy of saturated liquid
+       sSatVap = CP.PropsSI('S','T',T,'Q',1,nCP) # Entropy of saturated vapour
+       sSupVap = CP.PropsSI('S','T',T+dTRef,'P',p,nCP) # Entropy of superheated vapour
+       hSatLiq = CP.PropsSI('H','T',T,'Q',0,nCP) # Enthalpy of saturated liquid
+       hSatVap = CP.PropsSI('H','T',T,'Q',1,nCP) # Enthalpy of saturated vapour
+       hSupVap = CP.PropsSI('H','T',T+dTRef,'P',p,nCP) # Enthalpy of superheated vapour
+
+       with open(os.path.join(dirOutput, nMO + '.mo'), 'w') as f:
+           # header
+           f.write(f'within {WITHIN}Fluid.CHPs.OrganicRankine.Data.WorkingFluids;\n')
+           f.write(f'record {nMO} "Data record for {nDS}"\n')
+           f.write('  extends Generic(\n')
+
+           # data
+           f.write(' '*4 + f'T = {ModelicaArray(T)},\n')
+           f.write(' '*4 + f'p = {ModelicaArray(p)},\n')
+           f.write(' '*4 + f'rhoLiq = {ModelicaArray(rhoLiq)},\n')
+           f.write(' '*4 + f'dTRef = {str(dTRef)},\n')
+           f.write(' '*4 + f'sSatLiq = {ModelicaArray(sSatLiq)},\n')
+           f.write(' '*4 + f'sSatVap = {ModelicaArray(sSatVap)},\n')
+           f.write(' '*4 + f'sRef = {ModelicaArray(sSupVap)},\n')
+           f.write(' '*4 + f'hSatLiq = {ModelicaArray(hSatLiq)},\n')
+           f.write(' '*4 + f'hSatVap = {ModelicaArray(hSatVap)},\n')
+           f.write(' '*4 + f'hRef = {ModelicaArray(hSupVap)});\n')
+              
+           # annotation
+           f.write(' '*2 + 'annotation (\n')
+           f.write(' '*2 + 'defaultComponentPrefixes = "parameter",\n')
+           f.write(' '*2 + 'defaultComponentName = "pro",\n')
+           f.write(' '*2 + 'Documentation(info="<html>\n')
+           f.write('<p>\n')
+           f.write(f'Record containing properties of {nDS}.\n')
+           f.write(f'Its name in CoolProp is \\"{nCP}\\".\n')
+           f.write('A figure in the documentation of\n')
+           f.write(f'<a href=\\"Modelica://{WITHIN}Fluid.CHPs.OrganicRankine.ConstantEvaporation\\">\n')
+           f.write(f'{WITHIN}Fluid.CHPs.OrganicRankine.ConstantEvaporation</a>\n')
+           f.write('shows which lines these arrays represent.\n')
+           f.write('</p>\n')
+           f.write('</html>"));\n')
+           
+           # end
+           f.write(f'end {nMO};')
+       print(f'File written: {nMO}.mo')
+
+#######################################################################
+
+WriteOneFile(FLUIDNAME,dTRef = dTRef)
\ No newline at end of file

From 199e6a7cdd399536e65800130dd07cd60d3768a9 Mon Sep 17 00:00:00 2001
From: Michael Wetter <mwetter@lbl.gov>
Date: Thu, 17 Oct 2024 14:37:05 -0700
Subject: [PATCH 2/3] Replaced use_inputFilter with use_strokeTime

---
 Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
index 4fa8fbcb6f2..8d663ad1a24 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
@@ -95,7 +95,7 @@ model ORCHotWater "ORC that outputs hot water at a fixed temperature"
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
     T_start=TCol_start,
     from_dp=false,
-    use_inputFilter=false,
+    use_strokeTime=false,
     final m_flow_nominal=mCol_flow_nominal,
     final dpValve_nominal=dpValCol_nominal,
     final dpFixed_nominal=fill(dpCon_nominal, 2)) "Control valve"

From 8f962827bec337a25a4860f52843b15341ed3b7c Mon Sep 17 00:00:00 2001
From: Michael Wetter <mwetter@lbl.gov>
Date: Fri, 25 Oct 2024 12:53:16 -0700
Subject: [PATCH 3/3] Merged changes of ORC model from IBPSA

---
 .../CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo   | 3 ++-
 .../Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo      | 2 +-
 .../Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo     | 8 --------
 Buildings/Resources/Python-Sources/MakeORCFluidRecord.py  | 2 --
 4 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
index 4452b1cdb32..e533ca15bec 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/BaseClasses/FixedEvaporating.mo
@@ -112,7 +112,8 @@ model FixedEvaporating
   Modelica.Blocks.Logical.Hysteresis hys(
     uLow = mWor_flow_min,
     uHigh = mWor_flow_min + mWor_flow_hysteresis,
-    u = mWor_flow_internal)
+    u = mWor_flow_internal,
+    y(start = false))
     "Hysteresis for turning off cycle when working fluid flow too low";
 
 protected
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo b/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
index 3f44f3d5705..7398841abf2 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/ConstantEvaporation.mo
@@ -100,7 +100,7 @@ model ConstantEvaporation "Organic Rankine cycle as a bottoming cycle"
         iconTransformation(extent={{-10,-10},{10,10}},
         rotation=0,
         origin={110,-90})));
-  Modelica.Blocks.Interfaces.BooleanOutput on_actual
+  Modelica.Blocks.Interfaces.BooleanOutput on_actual(start = false)
     "Actual on off status of the cycle" annotation (Placement(transformation(
           extent={{100,-20},{140,20}}), iconTransformation(extent={{100,-10},{
             120,10}})));
diff --git a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
index 8d663ad1a24..7da72bd05fb 100644
--- a/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
+++ b/Buildings/Fluid/CHPs/OrganicRankine/Examples/ORCHotWater.mo
@@ -38,9 +38,6 @@ model ORCHotWater "ORC that outputs hot water at a fixed temperature"
     etaPum=0.6) "Organic Rankine cycle"
     annotation (Placement(transformation(extent={{-40,-44},{-20,-24}})));
 
-  Modelica.Units.SI.Efficiency etaThe =orc.PExp  / max(orc.QEva_flow,1)
-    "Thermal efficiency of the ORC";
-
   Buildings.Fluid.Sources.MassFlowSource_T souHot(
     redeclare final package Medium = MediumHot,
     m_flow=mHot_flow_nominal,
@@ -210,11 +207,6 @@ can be integrated in a system.
 The three-way valve is controlled to track the hot water
 output temperature, which is the cold fluid of the ORC,
 at a set point of 55&deg;C.
-The system and control are similar to the one implemented in
-<a href=\"Modelica://Buildings.DHC.ETS.Combined.Subsystems.Validation.Chiller\">
-Buildings.DHC.ETS.Combined.Subsystems.Validation.Chiller</a>.
-</p>
-<p>
 In addition, a safety control sequence prevents the ORC from turning on
 until a minimum flow rate is established in the condenser water loop.
 </p>
diff --git a/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py b/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
index 3ccf30ba8ad..2c8ad580a7c 100644
--- a/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
+++ b/Buildings/Resources/Python-Sources/MakeORCFluidRecord.py
@@ -58,8 +58,6 @@ def WriteOneFile(fluid, dTRef = 30):
        T = np.linspace(TMin,TMax,10)
        p = CP.PropsSI('P','T',T,'Q',1,nCP)
        rhoLiq = CP.PropsSI('D','T',T,'Q',0,nCP)
-       pMin = CP.PropsSI('P','T',TMin,'Q',1,nCP)
-       pMax = CP.PropsSI('P','T',TMax,'Q',1,nCP)
        
        sSatLiq = CP.PropsSI('S','T',T,'Q',0,nCP) # Entropy of saturated liquid
        sSatVap = CP.PropsSI('S','T',T,'Q',1,nCP) # Entropy of saturated vapour