model ElectricChillersDirectETS "Example model for district cooling system with an electric chiller plant and a direct controlled ETS at each building" extends Modelica.Icons.Example; package Medium=Buildings.Media.Water "Medium model for water"; // Chiller and cooling tower replaceable parameter Buildings.Fluid.Chillers.Data.ElectricEIR.ElectricEIRChiller_York_YT_1055kW_5_96COP_Vanes perChi "Performance data of chiller"; parameter Modelica.Units.SI.MassFlowRate mCHW_flow_nominal=18.3 "Nominal chilled water mass flow rate"; parameter Modelica.Units.SI.MassFlowRate mCW_flow_nominal=34.7 "Nominal condenser water mass flow rate"; parameter Modelica.Units.SI.PressureDifference dpCHW_nominal=44.8*1000 "Nominal chilled water side pressure"; parameter Modelica.Units.SI.PressureDifference dpCW_nominal=46.2*1000 "Nominal condenser water side pressure"; parameter Modelica.Units.SI.Pressure dpDis=30000 "Total pressure drop in the district pipes"; parameter Modelica.Units.SI.Power QChi_nominal=mCHW_flow_nominal*4200*(6.67-18.56) "Nominal cooling capaciaty (Negative means cooling)"; // Pumps parameter Buildings.Fluid.Movers.Data.Generic perCHWPum( pressure=Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters( V_flow=mCHW_flow_nominal/1000*{0.2,0.6,0.8,1.0}, dp=(dpCHW_nominal+dpDis+20000+6000*3)*{1,0.8,0.6,0.2})) "Performance data for chilled water pumps"; parameter Buildings.Fluid.Movers.Data.Generic perCWPum( pressure=Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters( V_flow=mCW_flow_nominal/1000*{0.2,0.6,1.0,1.2}, dp=(dpCW_nominal+6000*2)*{1,0.8,0.6,0.2})) "Performance data for condenser water pumps"; // Network parameter Integer nLoa=3 "Number of served loads"; final parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal[nLoa]=fill(10,nLoa) "Nominal mass flow rate in each connection line"; // Buildings parameter String filNam[nLoa]={ Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Experimental/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos"), Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Experimental/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos"), Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Experimental/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos")} "Library path of the file with thermal loads as time series"; final parameter Modelica.Units.SI.HeatFlowRate QCoo_flow_nominal[nLoa]( each max=-Modelica.Constants.eps)={Buildings.Experimental.DHC.Loads.BaseClasses.getPeakLoad( string="#Peak space cooling load", filNam=filNam[i]) for i in 1:nLoa} "Space cooling design load (<=0)"; final parameter Modelica.Units.SI.MassFlowRate mBui_flow_nominal[nLoa]( each final min=0, each final start=0.5)={-QCoo_flow_nominal[i]/(cp*buiETS[i].dT_nominal) for i in 1:nLoa} "Nominal mass flow rate of building cooling side"; Buildings.Experimental.DHC.Plants.Cooling.ElectricChillerParallel pla( perChi=perChi, dTApp=3, perCHWPum=perCHWPum, perCWPum=perCWPum, mCHW_flow_nominal=mCHW_flow_nominal, dpCHW_nominal=dpCHW_nominal, QChi_nominal=QChi_nominal, mMin_flow=mCHW_flow_nominal*0.25, mCW_flow_nominal=mCW_flow_nominal, dpCW_nominal=dpCW_nominal, TAirInWB_nominal=298.7, TCW_nominal=308.15, dT_nominal=5.56, TMin=288.15, PFan_nominal=5000, tau=60, yCHWP_start=fill(0, 2), yCWP_start=fill(0, 2), dpCooTowVal_nominal=6000, dpCHWPumVal_nominal=6000, dpCWPumVal_nominal=6000, tWai=30, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "District cooling plant"; Buildings.BoundaryConditions.WeatherData.ReaderTMY3 weaDat( final computeWetBulbTemperature=true, filNam=Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/weatherdata/USA_CA_San.Francisco.Intl.AP.724940_TMY3.mos")) "Weather data"; Modelica.Blocks.Sources.Constant TCHWSupSet(k=273.15+7) "Chilled water supply temperature setpoint"; Buildings.Experimental.DHC.Networks.Distribution2PipePlugFlow dis( redeclare final package Medium=Medium, nCon=nLoa, allowFlowReversal=false, mDis_flow_nominal=sum(dis.mCon_flow_nominal), mCon_flow_nominal=mBui_flow_nominal, mEnd_flow_nominal=mBui_flow_nominal[nLoa], length=fill(30, nLoa)) "Distribution network for district cooling system"; Buildings.Experimental.DHC.Loads.Cooling.BuildingTimeSeriesWithETS buiETS[nLoa]( each yMin=0.05, each use_inputFilter=true, filNam=filNam, mBui_flow_nominal=mBui_flow_nominal, each bui(w_aLoaCoo_nominal=0.015)) "Vectorized time series building load model connected with ETS for cooling"; Modelica.Blocks.Sources.Constant TDisRetSet(k=273.15 + 16) "Setpoint for district return temperature"; Modelica.Blocks.Math.Sum QTotCoo_flow(nin=nLoa) "Total cooling flow rate for all buildings "; Buildings.Controls.OBC.CDL.Reals.LessThreshold offCoo(t=1e-4) "Threshold comparison to disable the plant"; Modelica.Blocks.Math.Gain norQFlo(k=1/sum(QCoo_flow_nominal)) "Normalized Q_flow"; HeatTransfer.Sources.FixedTemperature gnd(T=285.15) "Ground"; Controls.OBC.CDL.Logical.Timer tim(t=3600); Controls.OBC.CDL.Logical.Not onPla "On signal for the plant"; protected parameter Modelica.Units.SI.SpecificHeatCapacity cp=Medium.specificHeatCapacityCp( Medium.setState_pTX( Medium.p_default, Medium.T_default, Medium.X_default)) "Default specific heat capacity of medium"; equation connect(weaDat.weaBus, pla.weaBus); connect(TCHWSupSet.y, pla.TCHWSupSet); connect(pla.port_aSerCoo, dis.port_bDisRet); connect(dis.port_aDisSup, pla.port_bSerCoo); connect(dis.ports_bCon, buiETS.port_aSerCoo); connect(buiETS.port_bSerCoo, dis.ports_aCon); for i in 1:nLoa loop connect(TDisRetSet.y, buiETS[i].TSetDisRet); end for; connect(buiETS.QCoo_flow, QTotCoo_flow.u); connect(QTotCoo_flow.y, norQFlo.u); connect(norQFlo.y, offCoo.u); connect(gnd.port, dis.heatPort); connect(offCoo.y, tim.u); connect(tim.passed, onPla.u); connect(onPla.y, pla.on); end ElectricChillersDirectETS;