Chiller plant sequences

Buildings/Applications/DataCenters/ChillerCooled/Examples/BaseClasses/PartialDataCenter.mo

@@ -171,18 +171,15 @@ partial model PartialDataCenter
     annotation (Placement(transformation(extent={{10,-10},{-10,10}},
         rotation=90,
         origin={-50,-150})));
-  Buildings.Examples.ChillerPlant.BaseClasses.SimplifiedRoom roo(
+  Buildings.Examples.ChillerPlants.DataCenter.BaseClasses.SimplifiedRoom roo(
     redeclare replaceable package Medium = MediumA,
     rooLen=50,
     rooWid=30,
     rooHei=3,
     m_flow_nominal=mAir_flow_nominal,
     QRoo_flow=500000,
-    nPorts=2)
-    "Room model"
-    annotation (Placement(transformation(
-        extent={{10,-10},{-10,10}},
-        origin={4,-180})));
+    nPorts=2) "Room model" annotation (Placement(transformation(extent={{10,-10},
+            {-10,10}}, origin={4,-180})));
   Buildings.Fluid.Actuators.Valves.TwoWayLinear val[numChi](
     redeclare each package Medium = MediumW,
     each m_flow_nominal=m1_flow_chi_nominal,

Buildings/Applications/DataCenters/DXCooled/Examples/DXCooledAirsideEconomizer.mo

@@ -38,7 +38,7 @@ model DXCooledAirsideEconomizer
   parameter Real minSpeFan = 0.2
     "Minimum fan speed ratio required by variable speed fans";
 
-  Buildings.Examples.ChillerPlant.BaseClasses.SimplifiedRoom roo(
+  Buildings.Examples.ChillerPlants.DataCenter.BaseClasses.SimplifiedRoom roo(
     redeclare package Medium = Medium,
     rooLen=50,
     rooHei=3,

Buildings/Controls/OBC/ASHRAE/PrimarySystem/ChillerPlant/Economizers/Controller.mo

@@ -0,0 +1,351 @@
+within Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers;
+block Controller "Waterside economizer (WSE) enable/disable status"
+
+  parameter Real holdPeriod(
+    final unit="s",
+    final quantity="Time")=1200
+    "WSE minimum on or off time"
+  annotation(Dialog(group="Enable parameters"));
+
+  parameter Real delDis(
+    final unit="s",
+    final quantity="Time")=120
+  "Delay disable time period"
+  annotation(Dialog(group="Enable parameters"));
+
+  parameter Real TOffsetEna(
+    final unit="K",
+    final quantity="TemperatureDifference")=2
+    "Temperature offset between the chilled water return upstream of WSE and the predicted WSE output"
+  annotation(Dialog(group="Enable parameters"));
+
+  parameter Real TOffsetDis(
+    final unit="K",
+    final quantity="TemperatureDifference")=1
+    "Temperature offset between the chilled water return upstream and downstream WSE"
+  annotation(Dialog(group="Enable parameters"));
+
+  parameter Real heaExcAppDes(
+    final unit="K",
+    final quantity="TemperatureDifference")=2
+    "Design heat exchanger approach"
+    annotation(Dialog(group="Design parameters"));
+
+  parameter Real cooTowAppDes(
+    final unit="K",
+    final quantity="TemperatureDifference")=2
+    "Design cooling tower approach"
+    annotation(Dialog(group="Design parameters"));
+
+  parameter Real TOutWetDes(
+    final unit="K",
+    final quantity="ThermodynamicTemperature",
+    displayUnit="degC")=288.15
+    "Design outdoor air wet bulb temperature"
+    annotation(Dialog(group="Design parameters"));
+
+  parameter Real hysDt(
+    final unit="K",
+    final quantity="TemperatureDifference")=1
+     "Deadband temperature used in hysteresis block"
+    annotation (Evaluate=true, Dialog(tab="Advanced", group="Hysteresis"));
+
+  parameter Real VHeaExcDes_flow(
+    final unit="m3/s",
+    final quantity="VolumeFlowRate",
+    displayUnit="m3/s")=0.015
+      "Design heat exchanger chilled water volume flow rate"
+    annotation(Dialog(group="Design parameters"));
+
+  parameter Real step(
+    final unit="1")=0.02
+    "Incremental step used to reduce or increase the water-side economizer tuning parameter"
+    annotation (Evaluate=true, Dialog(tab="Advanced", group="Tuning"));
+
+  parameter Real wseOnTimDec(
+    final unit="s",
+    final quantity="Time",
+    displayUnit="h") = 3600
+    "Economizer enable time needed to allow decrease of the tuning parameter"
+    annotation (Evaluate=true,Dialog(tab="Advanced", group="Tuning"));
+
+  parameter Real wseOnTimInc(
+    final unit="s",
+    final quantity="Time",
+    displayUnit="h") = 1800
+    "Economizer enable time needed to allow increase of the tuning parameter"
+    annotation (Evaluate=true,Dialog(tab="Advanced", group="Tuning"));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealInput TOutWet(
+    final unit="K",
+    displayUnit="degC",
+    final quantity="ThermodynamicTemperature")
+    "Outdoor air wet bulb temperature"
+    annotation (Placement(transformation(extent={{-220,80},{-180,120}}),
+        iconTransformation(extent={{-140,60},{-100,100}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatRet(
+    final unit="K",
+    displayUnit="degC",
+    final quantity="ThermodynamicTemperature")
+    "Chilled water return temperature upstream of the WSE"
+    annotation (Placement(transformation(extent={{-220,40},{-180,80}}),
+        iconTransformation(extent={{-140,20},{-100,60}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatRetDow(
+    final unit="K",
+    displayUnit="degC",
+    final quantity="ThermodynamicTemperature")
+    "Chilled water return temperature downstream of the WSE"
+    annotation (Placement(transformation(extent={{-220,0},{-180,40}}),
+        iconTransformation(extent={{-140,-20},{-100,20}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealInput uTowFanSpeMax(
+    final min=0,
+    final max=1,
+    final unit="1")
+    "Maximum cooling tower fan speed"
+    annotation (Placement(transformation(extent={{-220,-120},{-180,-80}}),
+    iconTransformation(extent={{-140,-100},{-100,-60}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealInput VChiWat_flow(
+    final quantity="VolumeFlowRate",
+    final unit="m3/s")
+    "Measured chilled water volume flow rate"
+    annotation (Placement(transformation(extent={{-220,-60},{-180,-20}}),
+    iconTransformation(extent={{-140,-60},{-100,-20}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y
+    "WSE enable/disable status"
+    annotation (Placement(transformation(extent={{180,60},{220,100}}),
+    iconTransformation(extent={{100,60},{140,100}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealOutput TWsePre(
+    final quantity="ThermodynamicTemperature",
+    displayUnit="degC",
+    final unit="K")
+    "Predicted waterside economizer outlet temperature"
+    annotation (Placement(transformation(extent={{180,-20},{220,20}}),
+      iconTransformation(extent={{100,-20},{140,20}})));
+
+  Buildings.Controls.OBC.CDL.Interfaces.RealOutput yTunPar
+    "Tuning parameter"
+    annotation (Placement(transformation(extent={{180,-110},{220,-70}}),
+      iconTransformation(extent={{100,-100},{140,-60}})));
+
+  Buildings.Controls.OBC.CDL.Continuous.LessThreshold enaTChiWatRet(
+    final t=delDis)
+    "Enable condition based on chilled water return temperature upstream and downstream WSE"
+    annotation (Placement(transformation(extent={{60,-20},{80,0}})));
+
+  Buildings.Controls.OBC.CDL.Continuous.Hysteresis enaTWet(
+    final uLow = TOffsetEna - hysDt/2,
+    final uHigh = TOffsetEna + hysDt/2)
+    "Enable condition based on the outdoor wet bulb temperature"
+    annotation (Placement(transformation(extent={{20,40},{40,60}})));
+
+protected
+  Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.Tuning wseTun(
+    final step=step,
+    final wseOnTimDec=wseOnTimDec,
+    final wseOnTimInc=wseOnTimInc)
+    "Tuning parameter for the WSE outlet temperature calculation"
+    annotation (Placement(transformation(extent={{-140,-100},{-120,-80}})));
+
+  Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.PredictedOutletTemperature wseTOut(
+    final heaExcAppDes=heaExcAppDes,
+    final cooTowAppDes=cooTowAppDes,
+    final TOutWetDes=TOutWetDes,
+    final VHeaExcDes_flow=VHeaExcDes_flow)
+    "Calculates the predicted WSE outlet temperature"
+    annotation (Placement(transformation(extent={{-100,40},{-80,60}})));
+
+  Buildings.Controls.OBC.CDL.Continuous.Add add2(
+    final k2=-1) "Adder"
+    annotation (Placement(transformation(extent={{-20,40},{0,60}})));
+
+  Buildings.Controls.OBC.CDL.Logical.Pre pre "Logical pre"
+    annotation (Placement(transformation(extent={{140,-60},{160,-40}})));
+
+  Buildings.Controls.OBC.CDL.Continuous.Add add1(
+    final k1=1,
+    final k2=-1) "Adder"
+    annotation (Placement(transformation(extent={{-100,-20},{-80,0}})));
+
+  Buildings.Controls.OBC.CDL.Logical.TrueFalseHold truFalHol(
+    final trueHoldDuration=holdPeriod,
+    final falseHoldDuration=holdPeriod)
+    "Keeps a signal constant for a given time period"
+    annotation (Placement(transformation(extent={{140,20},{160,40}})));
+
+  Buildings.Controls.OBC.CDL.Logical.And and2 "And"
+    annotation (Placement(transformation(extent={{100,40},{120,60}})));
+
+  Buildings.Controls.OBC.CDL.Continuous.Hysteresis hys(
+    final uLow = TOffsetDis - hysDt/2,
+    final uHigh = TOffsetDis + hysDt/2)
+    "Hysteresis comparing CHW temperatures upstream and downstream WSE"
+    annotation (Placement(transformation(extent={{-60,-20},{-40,0}})));
+
+  Buildings.Controls.OBC.CDL.Logical.Timer timer
+    "Measures the disable condition satisfied time "
+    annotation (Placement(transformation(extent={{20,-20},{40,0}})));
+
+  Buildings.Controls.OBC.CDL.Logical.FallingEdge falEdg
+    "Falling edge to indicate the moment of disable"
+    annotation (Placement(transformation(extent={{-100,-60},{-80,-40}})));
+
+  Buildings.Controls.OBC.CDL.Logical.TrueHoldWithReset truHol(
+    final duration=holdPeriod)
+    "Holds a true signal for a period of time right after disable"
+    annotation (Placement(transformation(extent={{-60,-60},{-40,-40}})));
+
+  Buildings.Controls.OBC.CDL.Logical.Nor nor
+    "Not either of the inputs"
+    annotation (Placement(transformation(extent={{-20,-20},{0,0}})));
+
+equation
+  connect(uTowFanSpeMax, wseTun.uTowFanSpeMax) annotation (Line(points={{-200,-100},
+          {-150,-100},{-150,-95},{-142,-95}}, color={0,0,127}));
+  connect(TOutWet, wseTOut.TOutWet)
+    annotation (Line(points={{-200,100},{-120,100},{-120,58},{-102,58}},
+    color={0,0,127}));
+  connect(VChiWat_flow, wseTOut.VChiWat_flow)
+    annotation (Line(points={{-200,-40},{-120,-40},{-120,50},{-102,50}},
+    color={0,0,127}));
+  connect(pre.y,wseTun.uWseSta)
+    annotation (Line(points={{162,-50},{170,-50},{170,-70},{-150,-70},{-150,-85},
+          {-142,-85}},color={255,0,255}));
+  connect(TChiWatRet, add1.u1)
+    annotation (Line(points={{-200,60},{-140,60},{-140,-4},{-102,-4}},
+          color={0,0,127}));
+  connect(truFalHol.y, pre.u)
+    annotation (Line(points={{162,30},{170,30},{170,-30},{130,-30},{130,-50},{138,-50}},
+          color={255,0,255}));
+  connect(truFalHol.y, y) annotation (
+    Line(points={{162,30},{170,30},{170,80},{200,80}}, color={255,0,255}));
+  connect(enaTWet.y, and2.u1)
+    annotation (Line(points={{42,50},{98,50}}, color={255,0,255}));
+  connect(truFalHol.u, and2.y)
+    annotation (Line(points={{138,30},{130,30},{130,50},{122,50}},
+    color={255,0,255}));
+  connect(timer.y, enaTChiWatRet.u)
+    annotation (Line(points={{42,-10},{58,-10}}, color={0,0,127}));
+  connect(TChiWatRetDow, add1.u2)
+    annotation (Line(points={{-200,20},{-160,20},{-160,-16},{-102,-16}},
+    color={0,0,127}));
+  connect(add1.y, hys.u)
+    annotation (Line(points={{-78,-10},{-62,-10}},color={0,0,127}));
+  connect(enaTChiWatRet.y, and2.u2) annotation (Line(points={{82,-10},{90,-10},{
+          90,42},{98,42}}, color={255,0,255}));
+  connect(wseTun.y, wseTOut.uTunPar) annotation (Line(points={{-119,-90},{-110,-90},
+          {-110,42},{-102,42}},color={0,0,127}));
+  connect(wseTOut.y, add2.u2) annotation (Line(points={{-78,50},{-50,50},{-50,44},
+          {-22,44}}, color={0,0,127}));
+  connect(TChiWatRet, add2.u1) annotation (Line(points={{-200,60},{-140,60},{-140,
+          70},{-50,70},{-50,56},{-22,56}}, color={0,0,127}));
+  connect(add2.y, enaTWet.u)
+    annotation (Line(points={{2,50},{18,50}}, color={0,0,127}));
+  connect(wseTun.y, yTunPar)
+    annotation (Line(points={{-119,-90},{200,-90}}, color={0,0,127}));
+  connect(nor.y, timer.u)
+    annotation (Line(points={{2,-10},{18,-10}}, color={255,0,255}));
+  connect(hys.y, nor.u1)
+    annotation (Line(points={{-38,-10},{-22,-10}}, color={255,0,255}));
+  connect(truHol.y, nor.u2) annotation (Line(points={{-38,-50},{-30,-50},{-30,
+          -18},{-22,-18}}, color={255,0,255}));
+  connect(falEdg.y, truHol.u)
+    annotation (Line(points={{-78,-50},{-62,-50}}, color={255,0,255}));
+  connect(pre.y, falEdg.u) annotation (Line(points={{162,-50},{170,-50},{170,
+          -70},{-120,-70},{-120,-50},{-102,-50}}, color={255,0,255}));
+  connect(wseTOut.y, TWsePre) annotation (Line(points={{-78,50},{-50,50},{-50,34},
+          {116,34},{116,0},{200,0}}, color={0,0,127}));
+
+  annotation (defaultComponentName = "wseSta",
+        Icon(graphics={
+        Rectangle(
+        extent={{-100,-100},{100,100}},
+        lineColor={0,0,127},
+        fillColor={255,255,255},
+        fillPattern=FillPattern.Solid),
+        Text(
+          extent={{-120,146},{100,108}},
+          lineColor={0,0,255},
+          textString="%name"),
+        Rectangle(
+          extent={{-82,64},{80,-56}},
+          lineColor={28,108,200},
+          fillColor={210,210,210},
+          fillPattern=FillPattern.Solid,
+          borderPattern=BorderPattern.Raised),
+        Polygon(
+          points={{-82,64},{-16,8},{-82,-56},{-82,64}},
+          lineColor={175,175,175},
+          fillColor={175,175,175},
+          fillPattern=FillPattern.Solid),
+        Rectangle(
+          extent={{6,60},{72,-52}},
+          lineColor={28,108,200},
+          lineThickness=0.5),
+        Line(
+          points={{6,-52},{72,60}},
+          color={28,108,200},
+          thickness=0.5)}),
+        Diagram(coordinateSystem(preserveAspectRatio=false,
+          extent={{-180,-120},{180,120}})),
+Documentation(info="<html>
+<p>
+Waterside economizer (WSE) control sequence per ASHRAE RP-1711, March 2020, section 5.2.3.
+It implements the enable/disable conditions as provided in sections 5.2.3.1. and 5.2.3.2.
+</p>
+<p>
+The sequence controls the WSE status as follows:
+</p>
+<ul>
+<li>
+Enable WSE if it has been disabled for at least <code>holdPeriod</code> of time and the chilled water return
+temperature (CHWRT) upstream of WSE, <code>TChiWatRet</code>, is greater than the WSE predicted heat
+exchanger leaving water temperature (PHXLWT) increased in <code>TOffsetEna</code>.
+</li>
+<li>
+Disable WSE if it has been enabled for at least <code>holdPeriod</code> of time and CHWRT downstream of
+WSE, <code>TChiWatRetDow</code>, is greater than <code>TChiWatRet</code> decreased in <code>TOffsetDis</code>
+for <code>delDis</code> time period.
+</li>
+</ul>
+<p>
+The following state machine chart illustrates the transitions between WSE enabled and disabled state:
+</p>
+<p align=\"center\">
+<img alt=\"Image of WSE enable-disable state machine chart\"
+src=\"modelica://Buildings/Resources/Images/Controls/OBC/ASHRAE/PrimarySystem/ChillerPlant/Economizer/WaterSideEconomizerEnableDisableStateGraph.png\"/>
+</p>
+<p>
+The WSE control sequence uses the following subsequences:
+</p>
+<ul>
+<li>
+Calculation of the PHXLWT at given conditions:
+<a href=\"modelica://Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.PredictedOutletTemperature\">
+Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.PredictedOutletTemperature</a>.
+</li>
+<li>
+Calculation of the tuning parameter used as an input to PHXLWT calculation:
+<a href=\"modelica://Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.Tuning\">
+Buildings.Controls.OBC.ASHRAE.PrimarySystem.ChillerPlant.Economizers.Subsequences.Tuning</a>.
+</li>
+</ul>
+</html>",
+revisions="<html>
+<ul>
+<li>
+January 19, 2021, by Milica Grahovac:<br/>
+Added state chart illustration.
+</li>
+<li>
+October 13, 2018, by Milica Grahovac:<br/>
+First implementation.
+</li>
+</ul>
+</html>"));
+end Controller;