block Controller "Head pressure controller for plants with headered condenser water pumps" parameter Boolean have_chiHeaPreCon = false "Flag indicating if there is head pressure control signal from chiller controller"; parameter Boolean have_WSE=true "True if the plant has waterside economizer. When the plant has waterside economizer, the condenser water pump speed must be variable"; parameter Boolean have_fixSpeConWatPum=false "Flag indicating if the plant has fixed speed condenser water pumps"; parameter Real minTowSpe=0.1 "Minimum cooling tower fan speed"; parameter Real minConWatPumSpe=0.1 "Minimum condenser water pump speed"; parameter Real minHeaPreValPos=0.1 "Minimum head pressure control valve position"; parameter Real minChiLif=10 "Minimum allowable lift at minimum load for chiller"; parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerType= Buildings.Controls.OBC.CDL.Types.SimpleController.PI "Type of controller"; parameter Real k=1 "Gain of controller"; parameter Real Ti( final unit="s", final quantity="Time")=0.5 "Time constant of integrator block"; parameter Real Td( final unit="s", final quantity="Time")=0.5 "Time constant of derivative block"; Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uChiHeaCon "Enabling chillers head pressure control: true = ON, false = OFF"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TConWatRet( final unit="K", displayUnit="degC", final quantity="ThermodynamicTemperature") if not have_chiHeaPreCon "Measured condenser water return temperature (condenser leaving)"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatSup( final unit="K", displayUnit="degC", final quantity="ThermodynamicTemperature") if not have_chiHeaPreCon "Measured chilled water supply temperature"; Buildings.Controls.OBC.CDL.Interfaces.RealInput desConWatPumSpe( final min=0, final max=1, final unit="1") if not have_fixSpeConWatPum "Design condenser water pump speed for current stage"; Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uWSE if have_WSE and (not have_fixSpeConWatPum) "Status of water side economizer: true = ON, false = OFF"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uHeaPreCon( final min=0, final max=1, final unit="1") if have_chiHeaPreCon "Chiller head pressure control loop signal from chiller controller"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yMaxTowSpeSet( final min=0, final max=1, final unit="1") "Maximum cooling tower speed setpoint"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yHeaPreConVal( final min=0, final max=1, final unit="1") if have_WSE or ((not have_WSE) and have_fixSpeConWatPum) "Head pressure control valve position"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yConWatPumSpeSet( final min=0, final max=1, final unit="1") if not have_fixSpeConWatPum "Condenser water pump speed setpoint"; Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.HeadPressure.Subsequences.ControlLoop chiHeaPreLoo( final minChiLif=minChiLif, final controllerType=controllerType, final k=k, final Ti=Ti, final Td=Td) if not have_chiHeaPreCon "Generate chiller head pressure control loop signal"; Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.HeadPressure.Subsequences.MappingWithoutWSE noWSE( final have_fixSpeConWatPum=have_fixSpeConWatPum, final minTowSpe=minTowSpe, final minConWatPumSpe=minConWatPumSpe, final minHeaPreValPos=minHeaPreValPos) if not have_WSE "Controlling equipments for plants without waterside economizer"; Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.HeadPressure.Subsequences.MappingWithWSE withWSE( final minTowSpe=minTowSpe, final minConWatPumSpe=minConWatPumSpe, final minHeaPreValPos=minHeaPreValPos) if have_WSE and (not have_fixSpeConWatPum) "Controlling equipments for plants with waterside economizer"; protected Buildings.Controls.OBC.CDL.Reals.Switch swi if have_chiHeaPreCon "Head pressure control from chiller controller"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant con( final k=0) if have_chiHeaPreCon "Constant"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes1( final message="If the plant has waterside economizer, the condenser water pump cannot be fix speed.") "Generate alert if the plant has waterside economizer and the condenser water pump has fix speed"; Buildings.Controls.OBC.CDL.Logical.Sources.Constant havWSE( final k=have_WSE) "Have waterside economizer"; Buildings.Controls.OBC.CDL.Logical.Sources.Constant fixSpe( final k=have_fixSpeConWatPum) "Fix speed condenser water pump"; Buildings.Controls.OBC.CDL.Logical.And fixSpeWSE "The plant has waterside economizer and the condenser water pump is fix speed"; Buildings.Controls.OBC.CDL.Logical.Not not1 "Logical not"; Buildings.Controls.OBC.CDL.Logical.Pre pre "Break loop"; equation connect(chiHeaPreLoo.TConWatRet, TConWatRet); connect(chiHeaPreLoo.TChiWatSup, TChiWatSup); connect(chiHeaPreLoo.yHeaPreCon, noWSE.uHeaPreCon); connect(chiHeaPreLoo.yHeaPreCon, withWSE.uHeaPreCon); connect(withWSE.uWSE, uWSE); connect(uHeaPreCon, swi.u1); connect(con.y, swi.u3); connect(swi.y, noWSE.uHeaPreCon); connect(swi.y, withWSE.uHeaPreCon); connect(noWSE.yMaxTowSpeSet, yMaxTowSpeSet); connect(withWSE.yHeaPreConVal, yHeaPreConVal); connect(withWSE.yMaxTowSpeSet, yMaxTowSpeSet); connect(withWSE.yConWatPumSpeSet, yConWatPumSpeSet); connect(desConWatPumSpe, withWSE.desConWatPumSpe); connect(noWSE.yConWatPumSpeSet, yConWatPumSpeSet); connect(noWSE.yHeaPreConVal, yHeaPreConVal); connect(desConWatPumSpe, noWSE.desConWatPumSpe); connect(havWSE.y, fixSpeWSE.u1); connect(fixSpe.y, fixSpeWSE.u2); connect(fixSpeWSE.y, not1.u); connect(not1.y, assMes1.u); connect(uChiHeaCon, pre.u); connect(pre.y, swi.u2); connect(pre.y, chiHeaPreLoo.uHeaPreEna); connect(pre.y, noWSE.uHeaPreEna); connect(pre.y, withWSE.uHeaPreEna); end Controller;