constant String buildingsRootFileLocation=
      Modelica.Utilities.Files.loadResource("modelica://Buildings/legal.html")
      "Path to top-level legal.html of the Buildings library (used to find the spawn executable)";

partial block PartialEnergyPlusObject "Partial definitions of an EnergyPlus object" extends Modelica.Blocks.Icons.Block; outer Buildings.ThermalZones.EnergyPlus_9_6_0.Building building "Building-level declarations"; protected constant String modelicaNameBuilding=building.modelicaNameBuilding "Name of the building to which this output variable belongs to"; constant String modelicaInstanceName=getInstanceName() "Name of this instance"; constant String spawnExe=building.spawnExe "Name of the spawn executable, without extension, such as spawn-0.2.0-d7f1e095f3"; constant String idfVersion = building.idfVersion "IDF version with underscore, used for error report"; final parameter String idfName=building.idfName "Name of the IDF file that contains this zone"; final parameter String epwName=building.epwName "Name of the EnergyPlus weather file (but with mos extension)"; final parameter Real relativeSurfaceTolerance=building.relativeSurfaceTolerance "Relative tolerance of surface temperature calculations"; final parameter Boolean usePrecompiledFMU=building.usePrecompiledFMU "Set to true to use pre-compiled FMU with name specified by fmuName"; final parameter String fmuName=building.fmuName "Specify if a pre-compiled FMU should be used instead of EnergyPlus (mainly for development)"; final parameter Buildings.ThermalZones.EnergyPlus_9_6_0.Types.LogLevels logLevel=building.logLevel "LogLevels of EnergyPlus output"; parameter Modelica.Units.SI.Time startTime(fixed=false) "Simulation start time"; function round input Real u; input Real accuracy; output Real y; algorithm y := if (u > 0) then floor( u/accuracy+0.5)*accuracy else ceil( u/accuracy-0.5)*accuracy; end round; initial equation startTime=time; end PartialEnergyPlusObject;

class SpawnExternalObject "Class used to couple the FMU to interact with a thermal zone" extends ExternalObject; impure function constructor "Construct to connect to a thermal zone in EnergyPlus" extends Modelica.Icons.Function; input Integer objectType "Type of the object (1: ThermalZone, 2: Schedule, 3: Actuator, 4: Surface)"; input Modelica.Units.SI.Time startTime "Start time of the simulation"; input String modelicaNameBuilding "Name of this Modelica building instance that connects to this thermal zone"; input String modelicaInstanceName "Name of the Modelica instance of this object"; input String spawnExe "Name of the spawn executable, without extension, such as spawn-0.2.0-d7f1e095f3"; input String idfVersion "IDF version with underscores, such as 9_6_0"; input String idfName "Name of the IDF"; input String epwName "Name of the weather file"; input Real relativeSurfaceTolerance "Relative tolerance of surface temperature calculations"; input String epName "Name of the object in EnergyPlus"; input Boolean usePrecompiledFMU "Set to true to use precompiled FMU with name specified by input fmuName"; input String fmuName "Specify if a pre-compiled FMU should be used instead of EnergyPlus (mainly for development)"; input String buildingsRootFileLocation "Name of top-level legal.html file of the Buildings library (used to find the spawn executable)"; input Buildings.ThermalZones.EnergyPlus_9_6_0.Types.LogLevels logLevel "LogLevels of EnergyPlus output"; input Boolean printUnit "Set to true to print units for OutputVariable object. Must be false for all other objects"; input String jsonName "Name of the object in the json configuration file"; input String jsonKeysValues "Keys and values string to be written to the json configuration file"; input String parOutNames[nParOut] "Names of parameter in modelDescription.xml file"; input String parOutUnits[nParOut] "Modelica units of the parameters"; input Integer nParOut "Number of parameters"; input String inpNames[nInp] "Names of inputs in modelDescription.xml file"; input String inpUnits[nInp] "Modelica units of the inputs"; input Integer nInp "Size of inpNames"; input String outNames[nOut] "Names of outputs in modelDescription.xml file"; input String outUnits[nOut] "Modelica units of the outputs"; input Integer nOut "Size of outNames"; input Integer derivatives_structure[nDer,2] "List of derivatives (1-based index, [i,j] means dy_i/du_j"; input Integer nDer "Size of derivatives"; input Real derivatives_delta[nDer] "Increments for derivative calculation"; output SpawnExternalObject adapter; external "C" adapter=allocate_Modelica_EnergyPlus_9_6_0( objectType, startTime, modelicaNameBuilding, modelicaInstanceName, spawnExe, idfVersion, idfName, epwName, relativeSurfaceTolerance, epName, usePrecompiledFMU, fmuName, buildingsRootFileLocation, logLevel, printUnit, jsonName, jsonKeysValues, parOutNames, nParOut, parOutUnits, nParOut, inpNames, nInp, inpUnits, nInp, outNames, nOut, outUnits, nOut, derivatives_structure, 2, nDer, derivatives_delta, nDer); end constructor; pure function destructor "Release storage" extends Modelica.Icons.Function; input SpawnExternalObject adapter; external "C" free_Modelica_EnergyPlus_9_6_0(adapter); end destructor; end SpawnExternalObject;

model ThermalZoneAdapter "Block that interacts with this EnergyPlus zone" extends Modelica.Blocks.Icons.Block; extends Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.Synchronize.ObjectSynchronizer; constant String modelicaNameBuilding "Name of the building to which this thermal zone belongs to"; constant String modelicaInstanceName=getInstanceName() "Name of this instance"; constant String spawnExe "Name of the spawn executable, without extension, such as spawn-0.2.0-d7f1e095f3"; constant String idfVersion "IDF version with underscore, used for error report"; parameter String idfName "Name of the IDF file that contains this zone"; parameter String epwName "Name of the Energyplus weather file including the epw extension"; parameter Real relativeSurfaceTolerance "Relative tolerance of surface temperature calculations"; parameter String zoneName "Name of the thermal zone as specified in the EnergyPlus input"; parameter Boolean usePrecompiledFMU=false "Set to true to use pre-compiled FMU with name specified by fmuName"; parameter String fmuName="" "Specify if a pre-compiled FMU should be used instead of EnergyPlus (mainly for development)"; parameter Buildings.ThermalZones.EnergyPlus_9_6_0.Types.LogLevels logLevel=Buildings.ThermalZones.EnergyPlus_9_6_0.Types.LogLevels.Warning "LogLevels of EnergyPlus output"; parameter Boolean setInitialRadiativeHeatGainToZero "If true, then the radiative heat gain sent from Modelica to EnergyPlus is zero during the model initialization"; parameter Integer nFluPor "Number of fluid ports (Set to 2 for one inlet and one outlet)"; final parameter Modelica.Units.SI.Area AFlo(fixed=false) "Floor area"; final parameter Modelica.Units.SI.Volume V(fixed=false) "Zone volume"; final parameter Real mSenFac( fixed=false) "Factor for scaling the sensible thermal mass of the zone air volume"; Modelica.Blocks.Interfaces.RealInput T( final unit="K", displayUnit="degC") "Zone air temperature"; Modelica.Blocks.Interfaces.RealInput X_w( final unit="kg/kg") "Zone air mass fraction in kg/kg total air"; Modelica.Blocks.Interfaces.RealInput m_flow[nFluPor]( each final unit="kg/s") "Mass flow rate"; Modelica.Blocks.Interfaces.RealInput TInlet[nFluPor]( each final unit="K", each displayUnit="degC") "Air inlet temperatures"; Modelica.Blocks.Interfaces.RealInput QGaiRad_flow( final unit="W") "Radiative heat gain"; Modelica.Blocks.Interfaces.RealOutput TRad( final unit="K", displayUnit="degC") "Radiative temperature"; Modelica.Blocks.Interfaces.RealOutput QCon_flow( final unit="W") "Convective sensible heat to be added to zone air"; Modelica.Blocks.Interfaces.RealOutput QLat_flow( final unit="W") "Latent heat to be added to zone air"; Modelica.Blocks.Interfaces.RealOutput QPeo_flow( final unit="W") "Total heat gain from people, to be used for optional computation of CO2 released"; protected constant Integer nParOut=3 "Number of parameter values retrieved from EnergyPlus"; constant Integer nInp=5 "Number of inputs"; constant Integer nOut=4 "Number of outputs"; constant Integer nDer=0 "Number of derivatives"; constant Integer nY=nOut+nDer+1 "Size of output vector of exchange function"; parameter Integer nObj( fixed=false, start=0) "Total number of Spawn objects in building"; Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.SpawnExternalObject adapter=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.SpawnExternalObject( objectType=1, startTime=startTime, modelicaNameBuilding=modelicaNameBuilding, modelicaInstanceName=modelicaInstanceName, spawnExe=spawnExe, idfVersion=idfVersion, idfName=idfName, epwName=epwName, relativeSurfaceTolerance=relativeSurfaceTolerance, epName=zoneName, usePrecompiledFMU=usePrecompiledFMU, fmuName=fmuName, buildingsRootFileLocation=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.buildingsRootFileLocation, logLevel=logLevel, printUnit=false, jsonName="zones", jsonKeysValues=" \"name\": \""+zoneName+"\"", parOutNames={"AFlo","V","mSenFac"}, parOutUnits={"m2","m3","1"}, nParOut=nParOut, inpNames={"T","X","mInlets_flow","TAveInlet","QGaiRad_flow"}, inpUnits={"K","1","kg/s","K","W"}, nInp=nInp, outNames={"TRad","QConSen_flow","QLat_flow","QPeo_flow"}, outUnits={"K","W","W","W"}, nOut=nOut, derivatives_structure=fill(fill(nDer,2),nDer), nDer=nDer, derivatives_delta=fill(0,nDer)) "Class to communicate with EnergyPlus"; ////////// // The derivative structure was: // derivatives_structure={{2,1}}, // nDer=nDer, // derivatives_delta={0.1} // This has been removed due to numerical noise, // see https://github.com/lbl-srg/modelica-buildings/issues/2358#issuecomment-819578850 ////////// Real yEP[nY] "Output of exchange function"; parameter Modelica.Units.SI.MassFlowRate m_flow_small(fixed=false) "Small mass flow rate used to avoid TAveInlet = 0"; parameter Modelica.Units.SI.Time startTime(fixed=false) "Simulation start time"; discrete Modelica.Units.SI.Time tNext "Next sampling time"; //Modelica.Units.SI.Time tNextEP(start=startTime-1, fixed=true) "Next sampling time requested from EnergyPlus"; // constant Real dT_dtMax(unit="K/s") = 0.000001 "Bound on temperature derivative to reduce or increase time step"; // Modelica.Units.SI.Time dtMax(displayUnit="min", start=600, fixed=true) "Maximum time step before next sampling"; discrete Modelica.Units.SI.Time tLast "Last time of data exchange"; discrete Modelica.Units.SI.Time dtLast "Time step since the last synchronization"; discrete Modelica.Units.SI.MassFlowRate mInlet_flow "Time averaged inlet mass flow rate"; discrete Modelica.Units.SI.Temperature TAveInlet "Time averaged inlet temperature"; discrete Modelica.Units.SI.Temperature TRooLast "Room air temperature at last sampling"; discrete Modelica.Units.SI.HeatFlowRate QGaiRadAve_flow "Radiative heat flow rate averaged over the past synchronization time step"; Modelica.Units.SI.Energy EGaiRad(unbounded=true) "Radiative energy exchanged since the start of the simulation"; discrete Modelica.Units.SI.Energy EGaiRadLast(unbounded=true) "Radiative energy exchanged at the last synchronization time step"; // discrete Real dQCon_flow_dT( // final unit="W/K") // "Derivative dQCon_flow / dT"; discrete Modelica.Units.SI.HeatFlowRate QConLast_flow(fixed=false, start=0) "Convective sensible heat to be added to zone air if T = TRooLast"; function round input Real u; input Real accuracy; output Real y; algorithm y := if (u > 0) then floor( u/accuracy+0.5)*accuracy else ceil( u/accuracy-0.5)*accuracy; end round; initial equation if usePrecompiledFMU then assert( Modelica.Utilities.Strings.length(fmuName) > 1, "If usePrecompiledFMU = true, must set parameter fmuName"); end if; nObj=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.initialize( adapter=adapter, isSynchronized=building.isSynchronized); {AFlo, V, mSenFac}=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.getParameters( adapter=adapter, nParOut=nParOut, isSynchronized=nObj); m_flow_small=V*3*1.2/3600*1E-10; startTime=time; // Initialization of output variables. TRooLast=T; dtLast=0; mInlet_flow=0; TAveInlet=T; QGaiRadAve_flow = if setInitialRadiativeHeatGainToZero then 0 else QGaiRad_flow; tLast=time; EGaiRad = 0; EGaiRadLast = 0; // Synchronization with EnergyPlus // Below, the term X_w/(1.-X_w) is for conversion from kg/kg_total_air (Modelica) to kg/kg_dry_air (EnergyPlus) yEP=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.exchange( adapter=adapter, nY=nY, u={ T, X_w/(1.-X_w), mInlet_flow, TAveInlet, QGaiRadAve_flow, round(time,1E-3)}, dummy=AFlo); TRad=yEP[1]; QConLast_flow=yEP[2]; QLat_flow=yEP[3]; QPeo_flow=yEP[4]; tNext=yEP[5]; assert(AFlo > 0, "Floor area must not be zero."); assert(V > 0, "Volume must not be zero."); assert(mSenFac > 0.9999, "mSenFac must be at least 1."); equation if usePrecompiledFMU then // For JModelica, this must be in the equation section rather than the initial equation section assert(Modelica.Utilities.Strings.length(fmuName) > 1, "If usePrecompiledFMU = true, must set parameter fmuName"); end if; // Integrate GQaiRad_flow, which breaks any algebraic loop if QGaiRad_flow is // a function of TRad der(EGaiRad) = QGaiRad_flow; // Synchronization with EnergyPlus when {time >= pre(tNext)} then // Initialization of output variables. TRooLast=T; dtLast=time-pre(tLast); mInlet_flow=noEvent( sum( if m_flow[i] > 0 then m_flow[i] else 0 for i in 1:nFluPor)); TAveInlet=noEvent( sum( if m_flow[i] > 0 then TInlet[i]*m_flow[i] else 0 for i in 1:nFluPor)+m_flow_small*pre(TAveInlet)/(mInlet_flow+m_flow_small)); // Below, the term X_w/(1.-X_w) is for conversion from kg/kg_total_air (Modelica) to kg/kg_dry_air (EnergyPlus) QGaiRadAve_flow = (EGaiRadLast-pre(EGaiRadLast))/dtLast; // Call EnergyPlus yEP=Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.exchange( adapter=adapter, nY=nY, u={T,X_w/(1.-X_w),pre(mInlet_flow),TAveInlet,QGaiRadAve_flow,round(time,1E-3)}, dummy=AFlo); // Assign return values of EnergyPlus TRad=yEP[1]; QConLast_flow=yEP[2]; QLat_flow=yEP[3]; QPeo_flow=yEP[4]; tNext=yEP[5]; tLast=time; // Store current value of exchanged radiative heat EGaiRadLast = EGaiRad; end when; //QCon_flow=QConLast_flow+(T-TRooLast)*dQCon_flow_dT; QCon_flow=QConLast_flow; synBui.synchronize.done=nObj; end ThermalZoneAdapter;

pure function exchange "Exchange the values with the EnergyPlus thermal zone" extends Modelica.Icons.Function; input Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.SpawnExternalObject adapter "External object"; input Integer nY "Size of output y"; input Real u[:] "Input values. First all inputs, then the current model time"; input Real dummy "Dummy value (used to force Modelica tools to call initialize())"; output Real y[nY] "Output values. First all outputs, then all derivatives, then next event time"; external "C" exchange_Modelica_EnergyPlus_9_6_0(adapter, u, dummy, y); end exchange;

pure function getParameters "Get parameters for an EnergyPlus object" extends Modelica.Icons.Function; input Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.SpawnExternalObject adapter "External object"; input Integer nParOut "Number of elements in parOut"; input Real isSynchronized "Set to variable that is used to synchronize the objects"; output Real parOut[nParOut] "Parameter values returned from EnergyPlus"; external "C" getParameters_Modelica_EnergyPlus_9_6_0( adapter,isSynchronized,parOut); end getParameters;

pure function getUnitAsString "Return the unit enumeration as a string" extends Modelica.Icons.Function; input Buildings.ThermalZones.EnergyPlus_9_6_0.Types.Units unit "Unit as enumeration value"; output String unitAsString "String representation of the unit"; algorithm unitAsString := if unit == Types.Units.Normalized then "1" elseif unit == Types.Units.AngleRad then "rad" elseif unit == Types.Units.AngleDeg then "deg" elseif unit == Types.Units.Energy then "J" elseif unit == Types.Units.Illuminance then "lm/m2" elseif unit == Types.Units.HumidityAbsolute then "kg/kg" elseif unit == Types.Units.HumidityRelative then "1" elseif unit == Types.Units.LuminousFlux then "cd.sr" elseif unit == Types.Units.MassFlowRate then "kg/s" elseif unit == Types.Units.Power then "W" elseif unit == Types.Units.Pressure then "Pa" elseif unit == Types.Units.Status then "1" elseif unit == Types.Units.Temperature then "K" elseif unit == Types.Units.Time then "s" elseif unit == Types.Units.VolumeFlowRate then "m3/s" else "error"; end getUnitAsString;

pure function initialize "Initialization for an EnergyPlus thermal zone" extends Modelica.Icons.Function; input Buildings.ThermalZones.EnergyPlus_9_6_0.BaseClasses.SpawnExternalObject adapter "External object"; input Real isSynchronized "Set to variable that is used to synchronize the objects"; output Integer nObj "Returns 1 from C, used to force synchronization"; external "C" initialize_Modelica_EnergyPlus_9_6_0( adapter,isSynchronized,nObj); end initialize;