model ChillerWSE "Example model of a simple liquid-cooled data center with chiller and water-side economizer" extends Modelica.Icons.Example; package MediumAir = Buildings.Media.Air(T_default=TDryBul_nominal) "Medium for air"; package MediumChi = Buildings.Media.Water "Medium for chilled water loop"; replaceable package MediumTow = Buildings.Media.Antifreeze.PropyleneGlycolWater( property_T=TTowSup_nominal, X_a=Buildings.Media.Antifreeze.Functions.PropyleneGlycolWater.volumeToMassFraction( phi=0.4, T=293.15)) constrainedby Modelica.Media.Interfaces.PartialSimpleMedium(T_default=TTowSup_nominal) "Medium for tower loop"; replaceable package MediumRac = Buildings.Media.Antifreeze.PropyleneGlycolWater( property_T=TRacSup_nominal, X_a=Buildings.Media.Antifreeze.Functions.PropyleneGlycolWater.volumeToMassFraction( phi=0.25, T=293.15)) constrainedby Modelica.Media.Interfaces.PartialSimpleMedium(T_default=TRacSup_nominal) "Medium for rack"; parameter Modelica.Units.SI.Power PRac = 1E6 "Total rack design power"; parameter Real fraWSE = 0.6 "Fraction of peak load covered by water side economizer"; parameter Real fraChi = 1-fraWSE "Fraction of peak load covered by chiller"; constant Modelica.Units.SI.TemperatureDifference dTRac_nominal(max=0) = -5 "Temperature difference rack loop"; constant Modelica.Units.SI.TemperatureDifference dTPla_nominal(max=0) = -5 "Temperature difference cooling plant loop"; constant Modelica.Units.SI.TemperatureDifference dTTow_nominal(max=0) = dTPla_nominal "Temperature difference tower water loop"; constant Modelica.Units.SI.Temperature TRacSup_nominal=273.15 + 45 "Supply coolant temperature to rack at design conditions"; constant Modelica.Units.SI.Temperature TRacRet_nominal=TRacSup_nominal-dTRac_nominal "Return coolant temperature from rack at design conditions"; constant Modelica.Units.SI.TemperatureDifference TApp_nominal = 3 "Approach temperature at heat exchangers"; constant Modelica.Units.SI.Temperature TPlaSup_nominal=TRacSup_nominal - TApp_nominal "Temperature from cooling plant to CDU at design conditions"; constant Modelica.Units.SI.Temperature TPlaRet_nominal=TPlaSup_nominal - dTPla_nominal "Temperature from CDU to cooling plant at design conditions"; constant Modelica.Units.SI.Temperature TTowRet_nominal=TPlaSup_nominal - TApp_nominal "Return temperature from cooling tower"; constant Modelica.Units.SI.Temperature TTowSup_nominal=TTowRet_nominal - dTTow_nominal "Supply temperature to cooling tower"; constant Modelica.Units.SI.Temperature TDryBul_nominal=273.15 + 36 "Design dry bulb temperature if WSE is used exclusively (with fraWSE=0.9999)"; parameter Modelica.Units.SI.MassFlowRate mRac_flow_nominal=PRac/( TRacRet_nominal - TRacSup_nominal)/MediumRac.cp_const "Rack mass flow rate at design conditions"; parameter Modelica.Units.SI.MassFlowRate mPla_flow_nominal=PRac/( TPlaRet_nominal -TPlaSup_nominal) /cpChi_default "Cooling loop water mass flow rate at design conditions"; parameter Modelica.Units.SI.PressureDifference dpVal_nominal( displayUnit="Pa")=20000 "Valve design pressure drop"; parameter Modelica.Units.SI.PressureDifference dpHexChi_nominal=80000 "Heat exchanger design pressure drop on chiller side"; parameter Modelica.Units.SI.PressureDifference dPRac_nominal = 60000 "Rack design pressure drop"; parameter Buildings.Fluid.DataCenters.Racks.Liquid.Data.OCP_1kW_OAM_PG25 datRac(PIT_nominal=PRac, m_flow_nominal=mRac_flow_nominal) "Performance data for IT rack"; parameter Real COPc_nominal=5 "Chiller COP"; parameter Real epsWSE_nominal(min=0.5, max=0.95) = QWSE_flow_nominal / (min(mWSEPla_flow_nominal*cpChi_default, mWSETow_flow_nominal*cpTow_default)*(TPlaRet_nominal-TTowRet_nominal)) "Effectiveness of water side economizer"; final parameter Modelica.Units.SI.HeatFlowRate QCon_flow_nominal = (1-fraWSE) * PRac * (1/COPc_nominal+1) "Design heat flow rate of condenser"; final parameter Modelica.Units.SI.HeatFlowRate QWSE_flow_nominal = fraWSE*PRac "Design heat flow rate of economizer"; final parameter Modelica.Units.SI.MassFlowRate mEva_flow_nominal(min=0)=mPla_flow_nominal "Nominal mass flow rate at condenser water, sized to circulate all water through it to meet set point when trim chiller is needed"; final parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal(min=0)=-QCon_flow_nominal/dTTow_nominal/cpTow_default "Nominal mass flow rate at condenser water"; final parameter Modelica.Units.SI.MassFlowRate mWSETow_flow_nominal(min=0)=-QWSE_flow_nominal/dTTow_nominal/cpTow_default "Nominal mass flow rate at WSE on tower side"; final parameter Modelica.Units.SI.MassFlowRate mWSEPla_flow_nominal(min=0)=-QWSE_flow_nominal/dTPla_nominal/cpChi_default "Nominal mass flow rate at WSE on chilled water side"; parameter Fluid.DataCenters.CDUs.LiquidToLiquid.Data.Generic_2MW datCDU( TApp_nominal=TApp_nominal, TRacOut_nominal=TRacSup_nominal, medPla=Buildings.Fluid.DataCenters.CDUs.Types.Media.Water, phiGlyPla=0, medRac=Buildings.Fluid.DataCenters.CDUs.Types.Media.PropyleneGlycol, phiGlyRac=0.25, Q_flow_nominal=-PRac, mPla_flow_nominal=mPla_flow_nominal, mRac_flow_nominal=mRac_flow_nominal, dpHexPla_nominal=dpHexChi_nominal, dpPumpExt_nominal=datRac.dp_nominal + valRac.dp_nominal + pipRacIn.dp_nominal + pipRacOut.dp_nominal) "Data record for CDU"; parameter Fluid.HeatExchangers.CoolingTowers.Data.DryCooler.Generic datCooTow( Q_flow_nominal=-PRac, TCooIn_nominal=TTowSup_nominal, TCooOut_nominal=TTowRet_nominal, dp_nominal=80000, ratCooAir_nominal=cpAir_default/cpTow_default, TAirIn_nominal=TDryBul_nominal) "Performance data for cooling tower"; Controls.OBC.CDL.Reals.Sources.Constant uti(k=0.6) "Utilization of hardware"; Buildings.Fluid.DataCenters.Racks.Liquid.ColdPlateR_P rac( redeclare package Medium = MediumRac, allowFlowReversal=false, dat=datRac, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Rack with cold plate heat exchangers, modeled for simplicity as one large rack"; Buildings.Fluid.Sources.Boundary_pT bou( redeclare package Medium = MediumChi, p(displayUnit="Pa") = 300000, nPorts=1) "Pressure boundary condition"; Buildings.Fluid.Sensors.TemperatureTwoPort senTCDU_a( redeclare package Medium = MediumChi, allowFlowReversal=false, m_flow_nominal=mPla_flow_nominal, tau=0) "Chilled water supply temperature"; Buildings.Fluid.DataCenters.CDUs.LiquidToLiquid.CDU_epsNTU cdu( redeclare package MediumPla = MediumChi, redeclare package MediumRac = MediumRac, show_T=true, final dat=datCDU, allowFlowReversalPla=false, allowFlowReversalRac=false, yPum_start=1) "CDU, modeled for simplicity as one large CDU"; Fluid.Sensors.TemperatureTwoPort senTCDU_b( redeclare package Medium = MediumChi, allowFlowReversal=false, m_flow_nominal=mPla_flow_nominal, tau=0) "Outlet temperature"; Fluid.Sensors.TemperatureTwoPort senTRac_a( redeclare package Medium = MediumRac, allowFlowReversal=false, m_flow_nominal=mRac_flow_nominal, tau=0) "Rack inlet temperature"; Fluid.Sensors.TemperatureTwoPort senTRac_b( redeclare package Medium = MediumRac, allowFlowReversal=false, m_flow_nominal=mRac_flow_nominal, tau=0) "Rack outlet temperature"; Controls.OBC.CDL.Reals.Sources.Constant dpSet(k=datCDU.dpPumpExt_nominal) "Set point for head"; Controls.OBC.CDL.Reals.Sources.Constant TSetRacIn(y(final unit="K", displayUnit="degC"), k( final unit="K", displayUnit="degC") = TRacSup_nominal) "Set point for rack inlet temperature"; Fluid.HeatExchangers.ConstantEffectiveness wse( redeclare package Medium1 = MediumTow, redeclare package Medium2 = MediumChi, m1_flow_nominal=mWSETow_flow_nominal, m2_flow_nominal=mWSEPla_flow_nominal, show_T=true, eps=epsWSE_nominal, dp2_nominal=dpHexChi_nominal, dp1_nominal=dpHexChi_nominal) "Water side economizer (Heat exchanger)"; Fluid.Chillers.Carnot_TEva chi( redeclare package Medium1 = MediumTow, redeclare package Medium2 = MediumChi, m1_flow_nominal=mCon_flow_nominal, m2_flow_nominal=mEva_flow_nominal, show_T=true, QEva_flow_nominal=-(1-fraWSE)*PRac, dTEva_nominal=TPlaSup_nominal -TPlaRet_nominal, dTCon_nominal=-dTTow_nominal, dp2_nominal=dpHexChi_nominal, dp1_nominal=dpHexChi_nominal, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Chiller"; Fluid.HeatExchangers.CoolingTowers.DryCooler cooTow( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, dat=datCooTow) "Cooling tower"; BoundaryConditions.WeatherData.ReaderTMY3 weaDat(filNam= ModelicaServices.ExternalReferences.loadResource("modelica://Buildings/Resources/weatherdata/USA_IL_Chicago-OHare.Intl.AP.725300_TMY3.mos"), computeWetBulbTemperature=false) "Weather data reader"; BoundaryConditions.WeatherData.Bus weaBus "Weather data bus"; Buildings.Fluid.Movers.Preconfigured.SpeedControlled_y pumEva( redeclare package Medium = MediumChi, addPowerToMedium=false, m_flow_nominal=mEva_flow_nominal, dp_nominal=dpHexChi_nominal) "Pump chiller evaporator"; Buildings.Fluid.Movers.Preconfigured.SpeedControlled_y pumWSEChi( redeclare package Medium = MediumChi, addPowerToMedium=false, m_flow_nominal=mWSEPla_flow_nominal, dp_nominal=dpHexChi_nominal) "Pump for water-side economizer"; Buildings.Fluid.Movers.Preconfigured.SpeedControlled_y pumTow( redeclare package Medium = MediumTow, allowFlowReversal=false, addPowerToMedium=false, riseTime=5, m_flow_nominal=mWSETow_flow_nominal, dp_nominal=dpHexChi_nominal + pipTowIn.dp_nominal + pipTowOut.dp_nominal) "Pump for tower loop"; Fluid.Sensors.TemperatureTwoPort senTWSE_b2( redeclare package Medium = MediumChi, m_flow_nominal=mWSEPla_flow_nominal, tau=0) "Chilled water outlet temperature of water side economizer"; Fluid.Movers.Preconfigured.SpeedControlled_y pumCon( redeclare package Medium = MediumTow, addPowerToMedium=false, m_flow_nominal=mCon_flow_nominal, dp_nominal=dpHexChi_nominal) "Pump for chiller condenser"; Fluid.Sensors.TemperatureTwoPort senTTow_b( redeclare package Medium = MediumTow, allowFlowReversal=false, m_flow_nominal=mWSETow_flow_nominal, tau=0) "Outlet water temperature of tower"; Fluid.FixedResistances.Junction jun1( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mWSETow_flow_nominal*{1,1,1}, dp_nominal={0,0,0}); Fluid.FixedResistances.Junction jun2(redeclare package Medium = MediumChi, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mPla_flow_nominal*{1,1,fraWSE}, dp_nominal={0,0,0}); Fluid.FixedResistances.Junction jun3(redeclare package Medium = MediumChi, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mPla_flow_nominal*{1,1,fraWSE}, dp_nominal={0,0,0}); Fluid.Sensors.TemperatureTwoPort senTEvaIn( redeclare package Medium = MediumChi, allowFlowReversal=false, m_flow_nominal=mPla_flow_nominal, tau=0) "Chiller inlet temperature to evaporator"; Fluid.FixedResistances.Junction jun4(redeclare package Medium = MediumChi, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mPla_flow_nominal*{1,1,fraChi}, dp_nominal={0,0,0}); Fluid.FixedResistances.Junction jun5(redeclare package Medium = MediumChi, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mPla_flow_nominal*{1,1,fraChi}, dp_nominal={0,0,0}); Fluid.Sensors.TemperatureTwoPort senTEvaOut( redeclare package Medium = MediumChi, m_flow_nominal=mEva_flow_nominal, tau=0) "Chilled water outlet temperature of chiller"; Fluid.Sensors.TemperatureTwoPort senTChi_b1( redeclare package Medium = MediumTow, m_flow_nominal=mCon_flow_nominal, tau=0) "Cooling tower water outlet temperature of chiller"; Fluid.Sensors.TemperatureTwoPort senTWSE_b1( redeclare package Medium = MediumTow, m_flow_nominal=mWSETow_flow_nominal, tau=0) "Cooling tower water outlet temperature of water side economizer"; Buildings.Fluid.Movers.Preconfigured.SpeedControlled_y pumWSECW( redeclare package Medium = MediumTow, addPowerToMedium=false, m_flow_nominal=mWSETow_flow_nominal, dp_nominal=dpHexChi_nominal) "Pump for water side economizer on cooling tower side"; Fluid.Movers.Preconfigured.FlowControlled_dp pumCDU( redeclare package Medium = MediumChi, allowFlowReversal=false, addPowerToMedium=false, use_riseTime=false, m_flow_nominal=mPla_flow_nominal, dp_nominal=dpHexChi_nominal + datCDU.dpValve_nominal + pipCDUIn.dp_nominal + pipCDUOut.dp_nominal) "Pump chilled water circuit"; Fluid.FixedResistances.Junction jun6( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mWSETow_flow_nominal*{1,1,1}, dp_nominal={0,0,0}); Fluid.FixedResistances.Junction jun7( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mWSETow_flow_nominal*{1,1,1}, dp_nominal={0,0,0}); Fluid.FixedResistances.Junction jun8( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mWSETow_flow_nominal*{1,1,1}, dp_nominal={0,0,0}); Controls.OBC.CDL.Reals.PID conTow( k=1, yMax=1, yMin=0.1, u_s(final unit="K", displayUnit="degC"), u_m(final unit="K", displayUnit="degC"), controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.PI, Ti=120, r=1, xi_start=1, reverseActing=false) "Controller for tower fan and pump"; Controls.OBC.CDL.Reals.Sources.Constant TSetEva(y(final unit="K", displayUnit ="degC"), k( final unit="K", displayUnit="degC") =TPlaSup_nominal) "Set point temperature for evaporator outlet temperature"; Controls.OBC.CDL.Reals.Sources.Constant pSetChiWatPum( y(final unit="Pa"), k(final unit="Pa") = pumCDU.dp_nominal) "Pressure setpoint for chilled water pump"; Controls.OBC.CDL.Reals.Hysteresis hysChi( uLow=0, uHigh=1, u(final unit="K")) "Hysteresis for chiller staging"; Controls.OBC.CDL.Conversions.BooleanToReal yPumChi(y(final unit="1"), realTrue(final unit="1")) "Control signal for chiller circulation pumps"; Fluid.Sources.Boundary_pT bou1( redeclare package Medium = MediumTow, p(displayUnit="Pa") = 300000, nPorts=1) "Pressure boundary condition"; Controls.OBC.CDL.Reals.AddParameter TOffSet( p=-1, y(final unit="K", displayUnit="degC")) "Offset for set point"; Modelica.Blocks.Sources.RealExpression PFan(y(final unit="W") = cooTow.PFan) "Power consumption of tower fans"; Modelica.Blocks.Sources.RealExpression PPum(y(final unit="W") = cdu.P + pumWSEChi.P + pumWSECW.P + pumEva.P + pumCon.P + pumTow.P) "Power consumption of pumps"; Modelica.Blocks.Sources.RealExpression PChi(y(final unit="W") = chi.P) "Power consumption of chiller"; Modelica.Blocks.Sources.RealExpression PIT(y(final unit="W") = rac.P) "Power consumption of IT"; BaseClasses.ElectricalEnergyMeter EFan "Energy meter"; BaseClasses.ElectricalEnergyMeter EPum "Energy meter"; BaseClasses.ElectricalEnergyMeter EChi "Energy meter"; BaseClasses.ElectricalEnergyMeter EPIT(y_start=1E-10) "Energy meter"; Modelica.Blocks.Math.MultiSum EFac(nu=4) "Electricity for facility"; Modelica.Blocks.Math.Division PUE "Power use effectiveness (not taking into account electrical losses)"; Fluid.Sensors.TemperatureTwoPort senTWSEMix( redeclare package Medium = MediumTow, allowFlowReversal=false, m_flow_nominal=mWSETow_flow_nominal, tau=0) "Water temperature cooling tower loop after WSE"; Fluid.Actuators.Valves.TwoWayLinear valByp( redeclare package Medium = MediumTow, m_flow_nominal=mCon_flow_nominal, final dpValve_nominal=dpVal_nominal, strokeTime=30) "Valve for condenser loop bypass"; Fluid.Actuators.Valves.TwoWayLinear valThr( redeclare package Medium = MediumTow, m_flow_nominal=mCon_flow_nominal, final dpValve_nominal=dpVal_nominal, strokeTime=30, y_start=0) "Valve for condenser loop from cooling tower"; Fluid.FixedResistances.Junction jun9( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mCon_flow_nominal*{1,1,1}, dp_nominal={0,0,0}) "Junction at condenser loop"; Fluid.FixedResistances.Junction jun10( redeclare package Medium = MediumTow, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=mCon_flow_nominal*{1,1,1}, dp_nominal={0,0,0}) "Junction at condenser loop["; Buildings.Fluid.Sensors.TemperatureTwoPort senTChi_a1( redeclare package Medium = MediumTow, m_flow_nominal=mCon_flow_nominal, tau=0) "Cooling tower water inlet temperature of chiller"; Controls.OBC.CDL.Reals.PIDWithReset conPIDCon( Ti=60, r=1, reverseActing=false, u_s( final unit="K", displayUnit="degC"), u_m( final unit="K", displayUnit="degC")) "Controller for minimum chiller lift"; Controls.OBC.CDL.Reals.AddParameter TLifMin(p( unit="K", displayUnit="K") = 10, u(final unit="K", displayUnit="degC"), y(final unit="K", displayUnit="degC")) "Minimum lift of chiller"; Controls.OBC.CDL.Reals.MultiplyByParameter invValSig(k=-1) "Invert valve signal"; Controls.OBC.CDL.Reals.AddParameter invValSig2(p=1) "Invert valve control signal"; Fluid.Sensors.TemperatureTwoPort senTTow_a( redeclare package Medium = MediumTow, allowFlowReversal=false, m_flow_nominal=mWSETow_flow_nominal, tau=0) "Inlet water temperature of tower"; Controls.OBC.CDL.Reals.AddParameter TOffSetWSE(p=-1) "Offset for set point for WSE control"; Fluid.Sensors.MassFlowRate senMasFloByEco(redeclare package Medium = MediumChi) "Mass flow rate sensor in economizer bypass"; Controls.OBC.CDL.Reals.PID conEcoPla( k=1, yMin=0.1, u_s(final unit="kg/s"), u_m(final unit="kg/s"), controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.PI, Ti=60, r=mWSEPla_flow_nominal, xi_start=1, reverseActing=false) "Controller for economizer pump on facility level"; Controls.OBC.CDL.Reals.Sources.Constant zer( k = 0) "Zero as a set point"; Fluid.Sensors.MassFlowRate senMasFlo3(redeclare package Medium = MediumTow) "Mass flow rate sensor"; Controls.OBC.CDL.Reals.Limiter yPumTow(uMax=1, uMin=0.1) "Pump control signal"; Controls.OBC.CDL.Reals.Sources.Constant zer1(k=0) "Zero as a set point"; Controls.OBC.CDL.Reals.PID conEcoTow( k=1, yMin=0.1, u_s(final unit="kg/s"), u_m(final unit="kg/s"), controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.PI, Ti=60, r=mWSETow_flow_nominal, xi_start=1, reverseActing=false) "Controller for economizer pump on tower loop"; Controls.OBC.CDL.Reals.Sources.Constant TSetTowRet(y(final unit="K", displayUnit="degC"), k( final unit="K", displayUnit="degC") = TTowRet_nominal) "Set point temperature for tower return temperature"; Controls.OBC.CDL.Reals.PID conPumTow( k=1, yMax=2, yMin=0, u_s(final unit="K", displayUnit="degC"), u_m(final unit="K", displayUnit="degC"), controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.PI, Ti=120, r=1, xi_start=1, reverseActing=false) "Controller for tower pump"; Controls.OBC.CDL.Reals.Subtract errTFre( u1(final unit="K", displayUnit="degC"), u2(final unit="K", displayUnit="degC")) "Temperature error after free cooling"; protected final parameter MediumAir.ThermodynamicState staAir_default=MediumAir.setState_pTX( T=MediumAir.T_default, p=MediumAir.p_default, X=MediumAir.X_default[1:MediumAir.nXi]) "Default state for air"; final parameter MediumTow.ThermodynamicState staTow_default=MediumTow.setState_pTX( T=MediumTow.T_default, p=MediumTow.p_default, X=MediumTow.X_default[1:MediumTow.nXi]) "Default state for tower loop fluid"; final parameter MediumChi.ThermodynamicState staChi_default=MediumChi.setState_pTX( T=MediumChi.T_default, p=MediumChi.p_default, X=MediumChi.X_default[1:MediumChi.nXi]) "Default state for chiller loop fluid"; public Controls.OBC.CDL.Reals.Limiter yFanTow(uMax=1, uMin=0.1) "Tower fan control signal based on economizer leaving temperature"; Controls.OBC.CDL.Reals.Max yTowFan "Fan control signal"; Fluid.Actuators.Valves.TwoWayLinear valRac( redeclare package Medium = MediumRac, m_flow_nominal=mRac_flow_nominal, final dpValve_nominal=dpVal_nominal, strokeTime=30, y_start=0) "Valve for rack flow control"; Controls.OBC.CDL.Reals.Sources.Constant TSetRacOut(y(final unit="K", displayUnit="degC"), k( final unit="K", displayUnit="degC") = TRacRet_nominal) "Set point for rack outlet temperature"; Controls.OBC.CDL.Reals.PID conVal( Ti=60, yMin=0.05, u_s(final unit="K", displayUnit="degC"), u_m(final unit="K", displayUnit="degC"), final controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.PI, final reverseActing=false) "Controller for valve"; Modelica.Blocks.Math.Gain PITIn( k(final unit="W", min=0) = datRac.PIT_nominal, u(final unit="1"), y(final unit="W")) "Power consumption by the IT equipment"; replaceable model Pipe = Fluid.FixedResistances.HydraulicDiameter constrainedby Fluid.FixedResistances.HydraulicDiameter ( show_T=true, v_nominal=5, roughness=0.015E-3, length=20, fac=2) "Pipe model"; Pipe pipTowIn( redeclare package Medium = MediumTow, m_flow_nominal=mWSETow_flow_nominal) "Pipe at tower inlet"; Pipe pipTowOut( redeclare package Medium = MediumTow, m_flow_nominal=mWSETow_flow_nominal) "Pipe at tower outlet"; Pipe pipCDUIn( redeclare package Medium = MediumChi, allowFlowReversal=false, m_flow_nominal=mPla_flow_nominal) "Pipe at CDU inlet"; Pipe pipCDUOut( redeclare package Medium = MediumChi, allowFlowReversal=false, m_flow_nominal=mPla_flow_nominal) "Pipe at CDU outlet"; Pipe pipRacIn( redeclare package Medium = MediumRac, allowFlowReversal=false, m_flow_nominal=mRac_flow_nominal) "Pipe at rack inlet"; Pipe pipRacOut( redeclare package Medium = MediumRac, allowFlowReversal=false, m_flow_nominal=mRac_flow_nominal) "Pipe at rack outlet"; protected parameter Modelica.Units.SI.SpecificHeatCapacity cpAir_default= MediumAir.specificHeatCapacityCp(staAir_default) "Specific heat capacity of air at nominal condition"; parameter Modelica.Units.SI.SpecificHeatCapacity cpTow_default= MediumTow.specificHeatCapacityCp(staTow_default) "Specific heat capacity of tower loop fluid at nominal condition"; parameter Modelica.Units.SI.SpecificHeatCapacity cpChi_default= MediumChi.specificHeatCapacityCp(staChi_default) "Specific heat capacity of chiller loop fluid at nominal condition"; equation connect(senTCDU_a.port_b, cdu.port_aPla); connect(cdu.port_bPla, senTCDU_b.port_a); connect(rac.port_b, senTRac_b.port_a); connect(pumCDU.port_b, jun3.port_1); connect(jun2.port_2, senTEvaIn.port_a); connect(senTEvaIn.port_b, jun4.port_1); connect(jun4.port_2, jun5.port_1); connect(jun4.port_3,pumEva. port_a); connect(pumEva.port_b, chi.port_a2); connect(chi.port_b2,senTEvaOut. port_a); connect(senTEvaOut.port_b, jun5.port_3); connect(jun3.port_3, pumWSEChi.port_a); connect(pumWSEChi.port_b, wse.port_a2); connect(wse.port_b2, senTWSE_b2.port_a); connect(senTWSE_b2.port_b, jun2.port_3); connect(wse.port_b1, senTWSE_b1.port_a); connect(wse.port_a1, pumWSECW.port_b); connect(chi.port_b1, senTChi_b1.port_a); connect(jun1.port_3, pumWSECW.port_a); connect(jun8.port_1, jun7.port_2); connect(cooTow.port_b, senTTow_b.port_a); connect(weaBus, weaDat.weaBus); connect(pSetChiWatPum.y, pumCDU.dp_in); connect(hysChi.y,yPumChi. u); connect(TOffSet.u, TSetEva.y); connect(PFan.y, EFan.u); connect(PPum.y, EPum.u); connect(PChi.y, EChi.u); connect(PIT.y, EPIT.u); connect(EChi.y, EFac.u[1]); connect(EPum.y, EFac.u[2]); connect(EFan.y, EFac.u[3]); connect(EFac.y, PUE.u1); connect(EPIT.y, PUE.u2); connect(EPIT.y, EFac.u[4]); connect(jun7.port_1,senTWSEMix. port_b); connect(senTWSEMix.port_a, jun6.port_2); connect(jun7.port_3, valThr.port_a); connect(jun8.port_3, jun10.port_1); connect(jun10.port_3, valByp.port_a); connect(valThr.port_b, jun9.port_1); connect(jun9.port_2, pumCon.port_a); connect(valByp.port_b, jun9.port_3); connect(chi.port_a1, senTChi_a1.port_b); connect(senTChi_a1.port_a, pumCon.port_b); connect(senTChi_a1.T, conPIDCon.u_m); connect(senTEvaIn.T, TLifMin.u); connect(hysChi.y, conPIDCon.trigger); connect(TLifMin.y, conPIDCon.u_s); connect(conPIDCon.y, valThr.y); connect(invValSig2.u, invValSig.y); connect(invValSig2.y, valByp.y); connect(invValSig.u, conPIDCon.y); connect(pumEva.y, yPumChi.y); connect(pumCon.y, yPumChi.y); connect(cooTow.port_a, senTTow_a.port_b); connect(cooTow.TDryBul, weaBus.TDryBul); connect(jun3.port_2, senMasFloByEco.port_a); connect(senMasFloByEco.port_b, jun2.port_1); connect(senMasFloByEco.m_flow, conEcoPla.u_m); connect(zer.y, conEcoPla.u_s); connect(conEcoPla.y, pumWSEChi.y); connect(yPumTow.y, pumTow.y); connect(jun6.port_1, senMasFlo3.port_b); connect(senMasFlo3.port_a, jun1.port_2); connect(zer1.y, conEcoTow.u_s); connect(conEcoTow.y, pumWSECW.y); connect(conEcoTow.u_m, senMasFlo3.m_flow); connect(jun8.port_2, pumTow.port_a); connect(jun6.port_3, senTWSE_b1.port_b); connect(jun10.port_2, senTChi_b1.port_b); connect(TOffSetWSE.y, conTow.u_s); connect(conTow.u_m, senTTow_b.T); connect(TSetTowRet.y, TOffSetWSE.u); connect(conPumTow.u_s, TOffSet.y); connect(conPumTow.u_m, senTEvaIn.T); connect(conPumTow.y, yPumTow.u); connect(dpSet.y, cdu.dpSet); connect(TSetRacIn.y, cdu.TSet); connect(senTEvaIn.T, errTFre.u1); connect(errTFre.u2, TOffSet.y); connect(errTFre.y, hysChi.u); connect(TSetEva.y, chi.TSet); connect(conTow.y, yTowFan.u1); connect(yTowFan.y, cooTow.y); connect(errTFre.y, yFanTow.u); connect(conTow.y, yTowFan.u2); connect(rac.port_a, valRac.port_b); connect(valRac.port_a, senTRac_a.port_b); connect(TSetRacOut.y, conVal.u_s); connect(conVal.y, valRac.y); connect(senTRac_b.T, conVal.u_m); connect(uti.y, PITIn.u); connect(PITIn.y, rac.P); connect(pumCDU.port_a, bou.ports[1]); connect(jun1.port_1, bou1.ports[1]); connect(senTTow_a.port_a, pipTowIn.port_b); connect(pipTowIn.port_a, pumTow.port_b); connect(senTTow_b.port_b, pipTowOut.port_a); connect(pipTowOut.port_b, jun1.port_1); connect(senTCDU_a.port_a, pipCDUIn.port_b); connect(pipCDUIn.port_a, jun5.port_2); connect(senTCDU_b.port_b, pipCDUOut.port_a); connect(pipCDUOut.port_b, pumCDU.port_a); connect(cdu.port_bRac, pipRacIn.port_a); connect(pipRacIn.port_b, senTRac_a.port_a); connect(senTRac_b.port_b, pipRacOut.port_a); connect(pipRacOut.port_b, cdu.port_aRac); end ChillerWSE;

model ChillerWSEDynamicPipes "Example model of a simple liquid cooled data center with chiller and water-side economizer" extends ChillerWSE( break uti, redeclare model Pipe = MyPlugFlowPipe, datCDU(strokeTime=5), cdu( kVal=1, TiVal=30, kPum=0.5, TiPum=30)); Controls.OBC.CDL.Reals.Sources.TimeTable utiLiq( table=[ 0, 0.5; 120,0.5; 120,0.7; 240,0.7], extrapolation=Buildings.Controls.OBC.CDL.Types.Extrapolation.Periodic) "Utilization of liquid-cooled hardware"; model MyPlugFlowPipe extends Buildings.Fluid.FixedResistances.PlugFlowPipe( show_T=true, have_pipCap=true, v_nominal=5, dIns=0.01, kIns=0.04, cPip=500, rhoPip=800); // Introduce dp_nominal as this is used in the base class to size the pumps, // but the model Buildings.Fluid.FixedResistances.PlugFlowPipe // has no such top-level parameter final parameter Modelica.Units.SI.PressureDifference dp_nominal = res.dp_nominal "Design pressure drop"; final parameter Modelica.Units.SI.MassFlowRate m_flow_turbulent = res.m_flow_turbulent "Mass flow rate where transition to turbulent flow occurs"; final parameter Real deltaM = res.deltaM "Normmalized mass flow rate where transition to turbulent flow occurs"; final parameter Real k = res.k "Flow coefficient, k=m_flow/dp^(1/n)"; final parameter Modelica.Units.SI.PressureDifference dpStraightPipe_nominal = res.dpStraightPipe_nominal "Pressure loss of a round cross section pipe at m_flow_nominal"; end MyPlugFlowPipe; equation connect(utiLiq.y[1], PITIn.u); end ChillerWSEDynamicPipes;

replaceable model Pipe = Fluid.FixedResistances.HydraulicDiameter constrainedby Fluid.FixedResistances.HydraulicDiameter ( show_T=true, v_nominal=5, roughness=0.015E-3, length=20, fac=2) "Pipe model";

model MyPlugFlowPipe extends Buildings.Fluid.FixedResistances.PlugFlowPipe( show_T=true, have_pipCap=true, v_nominal=5, dIns=0.01, kIns=0.04, cPip=500, rhoPip=800); // Introduce dp_nominal as this is used in the base class to size the pumps, // but the model Buildings.Fluid.FixedResistances.PlugFlowPipe // has no such top-level parameter final parameter Modelica.Units.SI.PressureDifference dp_nominal = res.dp_nominal "Design pressure drop"; final parameter Modelica.Units.SI.MassFlowRate m_flow_turbulent = res.m_flow_turbulent "Mass flow rate where transition to turbulent flow occurs"; final parameter Real deltaM = res.deltaM "Normmalized mass flow rate where transition to turbulent flow occurs"; final parameter Real k = res.k "Flow coefficient, k=m_flow/dp^(1/n)"; final parameter Modelica.Units.SI.PressureDifference dpStraightPipe_nominal = res.dpStraightPipe_nominal "Pressure loss of a round cross section pipe at m_flow_nominal"; end MyPlugFlowPipe;