Merge pull request #6338 from NREL/VAVDesignMinFlow6327

Fix VAV min flow frac > 1.0 and a bunch of termunitsizing issues related to multiple airloops

doc/engineering-reference/src/loop-equipment-sizing-and-other-design-data/system-design-loads-and-air-flow-rates.tex

@@ -81,6 +81,8 @@ \subsection{System Design Flow Rate and Load Summation and Adjustment}\label{sys
 
 There is a logical flag \emph{SysSizingCalc} corresponding to \emph{ZoneSizingCalc}. It is used to allow the component routines to distinguish a normal simulation call from a being called during a system sizing calculation.
 
+\emph{Note that throughout this section, any reference to a ``zone'' is equivalent to ``air terminal unit''}.
+
 \subsubsection{BeginDay}\label{beginday}
 
 \begin{enumerate}

doc/engineering-reference/src/loop-equipment-sizing-and-other-design-data/zone-design-loads-and-air-flow-rates.tex

@@ -20,7 +20,9 @@ \subsection{Zone Design Data Arrays}\label{zone-design-data-arrays}
 
 \emph{FinalZoneSizing(i)} corresponds to \emph{CalcFinalZoneSizing} but includes the effect of the user specified sizing factor or user specified zone design flow rate.
 
-The data stored in \emph{CalcZoneSizing}, \emph{CalcFinalZoneSizing}, \emph{ZoneSizing} and \emph{FinalZoneSizing} includes the following data items.
+\emph{TermUnitFinalZoneSizing(k)} corresponds to \emph{FinalZoneSizing} but includes the effect of any air system terminal unit sizing factors input with DesignSpecification:AirTerminal:Sizing objects. The index k is for each air terminal unit. There may be more or less terminal units than there are controlled zones.
+
+The data stored in \emph{CalcZoneSizing}, \emph{CalcFinalZoneSizing}, \emph{ZoneSizing}, \emph{FinalZoneSizing} and \emph{TermUnitFinalZoneSizing} includes the following data items.
 
 % table 40
 \begin{longtable}[c]{p{1.85in}p{4.13in}}
@@ -36,7 +38,7 @@ \subsection{Zone Design Data Arrays}\label{zone-design-data-arrays}
 \midrule
 \endhead
 
-All the data from ZoneSizingInput &  \tabularnewline
+Select data from ZoneSizingInput &  \tabularnewline
 DesHeatMassFlow & the zone design heating air mass flow rate in [kg/s] \tabularnewline
 DesCoolMassFlow & the zone design cooling air mass flow rate in [kg/s] \tabularnewline
 DesHeatLoad & the zone design heating load in [W] \tabularnewline
@@ -206,9 +208,61 @@ \subsubsection{EndZoneSizingCalc}\label{endzonesizingcalc}
 
 \textbf{This concludes the calculation of the zone design flow rates and loads.}
 
+\subsection{Air Terminal Unit Sizing}\label{air-terminal-unit-sizing}
+
+Each controlled zone may have one or more air terminal units (AirTerminal:*) served by one or more central air handlers (AirLoopHVAC). Each air terminal unit may reference a DesignSpecification:AirTerminal:Sizing object which is used to adjust the \emph{FinalZoneSizing} data for each terminal unit with these user inputs:
+
+\begin{tabular}{lp{0.7\linewidth}}
+\\
+		$DesSensCoolingFrac$ &= Fraction of Design Sensible Cooling Load\\
+		$DesCoolSATRatio$ &= Cooling Design Supply Air Temperature Difference Ratio\\
+		$DesSensHeatingFrac$ &= Fraction of Design Sensible Heating Load\\
+		$DesHeatSATRatio$ &= Heating Design Supply Air Temperature Difference Ratio\\
+	  $MinOAFrac$ &= Fraction of Minimum Outdoor Air Flow\\
+\\
+\end{tabular}
+
+All of these factors default to 1.0. Function \emph{UpdateTermUnitFinalZoneSizing} first fills each instance of \emph{TermUnitFinalZoneSizing} with a copy of \emph{FinaZoneSizing} for the controlled zone served by the terminal unit. Then, if there is an applicable DesignSpecification:AirTerminal:Sizing input, the following adjustments are made:
+
+\begin{equation}
+    {CoolLoad_{TU}} = {CoolLoad_{FZ}} \cdot {DesSensCoolingFrac}
+\end{equation}
+
+\begin{equation}
+    {minOAFlow_{TU}} = {minOAFlow_{FZ}} \cdot {MinOAFrac}
+\end{equation}
+
+\begin{equation}
+    {CoolFlowRatio} = {DesSensCoolingFrac} / {DesCoolSATRatio}
+\end{equation}
+
+{\scriptsize
+\begin{equation}
+    {CoolFlow_{TU}} = {CoolFlowNoOA_{FZ}} \cdot CoolFlowRatio + {MinOAFrac} \cdot ( {CoolFlowWithOA_{FZ}} - {CoolFlowNoOA_{FZ}} ) 
+\end{equation}}
+
+\begin{equation}
+    {CoolFlow_{TU}} = max({CoolFlow_{TU}},{minOAFlow_{TU}}) 
+\end{equation}
+
+Where:
+
+\begin{tabular}{lp{0.7\linewidth}}
+\\
+    $CoolLoad$ &= Cooling load variables: $DesCoolLoad, CoolLoadSeq, NonAirSysDesCoolLoad$\\
+    $CoolFlow$ &= Cooling flow variables: $DesCoolVolFlow, CoolFlowSeq$\\
+    $CoolFlowNoOA$ &= Cooling flow variables not adjusted for minimum outdoor air: $DesCoolVolFlowNoOA, CoolFlowSeqNoOA$\\
+    $minOAFlow$ &= minimum outdoor air flow rate\\
+    Subscript $FZ$ &= Value from $FinalZoneSizing$\\
+    Subscript $TU$ &= Value for $TermUnitFinalZoneSizing$\\
+\\
+\end{tabular}
+
+Likewise for heating.
+
 \subsection{Zone HVAC Scalable Sizing}\label{zone-hvac-scalable-sizing}
 
-For zone HVAC equipments scalable sizing applies to supply air flow rate and capacity for both cooling and heating. The scalable sizing method allowed for supply air flow rates include: \emph{FractionOfAutosizedCoolingAirflow}, \emph{FractionOfAutosizedHeatingAirflow}, \emph{FlowPerFloorArea, FlowPerCoolingCapacity}, and \emph{FlowPerHeatingCapacity}. The supply air flow rate scalable sizing methods are defined as follows:
+For zone HVAC equipment, scalable sizing applies to supply air flow rate and capacity for both cooling and heating. The scalable sizing method allowed for supply air flow rates include: \emph{FractionOfAutosizedCoolingAirflow}, sizing method allowed for supply air flow rates include: \emph{FractionOfAutosizedCoolingAirflow}, \emph{FractionOfAutosizedHeatingAirflow}, \emph{FlowPerFloorArea, FlowPerCoolingCapacity}, and \emph{FlowPerHeatingCapacity}. The supply air flow rate scalable sizing methods are defined as follows:
 
 \textbf{\emph{FlowPerFloorArea}}: the simulation engine determine the supply air flow rates from the user specified \emph{supply air flow rates per unit floor area} and the zone floor area of the zone served by the zone HVAC equipment.
 

doc/input-output-reference/src/overview/group-design-objects.tex

@@ -1522,13 +1522,6 @@ \subsection{DesignSpecification:AirTerminal:Sizing}\label{designspecificationair
 
 This object modifies the sizing of an air loop terminal unit. It may be referenced by a ZoneHVAC:AirDistributionUnit or AirTerminal:SingleDuct:Uncontrolled object. The values specified here are applied to the base sizing results from the corresponding Sizing:Zone inputs. Any given DesignSpecification:AirTerminal:Sizing object may be used by multiple terminal units with similar characteristics.
 
-This feature has the following limitations:
-\begin{itemize}
-\item It does not work with VRP sizing.
-\item It does not work with a specified system flow rate in Sizing:System.
-\item It does not work if the base minimum outdoor air flow exceeds the heating or cooling air flow.
-\end{itemize}
-
 \subsubsection{Inputs}\label{inputs-52-007}
 
 \paragraph{Field: Name}\label{field-name-2-009}

src/EnergyPlus/AirTerminalUnit.hh

@@ -149,6 +149,10 @@ public: // Methods
 	Real64
 	getPrimAirDesignVolFlow() = 0;
 
+	virtual
+	int
+	getTermUnitSizingIndex() = 0;
+
 protected: // Data
 
 	AirTerminalUnitType terminalType; // Type of air distribution unit  //Legacy For use during transition to OO
@@ -166,6 +170,7 @@ protected: // Data
 	int zoneNodeIndex; // index in node structure for the zone node for this air terminal
 	int ctrlZoneInNodeIndex; // which controlled zone inlet node number corresponds with this unit
 	int airLoopNum; // index to airloop that this terminal unit is connected to
+	int termUnitSizingNum; // index to TermUnitSizing, TermUnitFinalZoneSizing, and more for this air distribution unit
 }; // AirTerminalUnit
 
 } // EnergyPlus

src/EnergyPlus/DataSizing.cc

@@ -344,12 +344,6 @@ namespace DataSizing {
 	Array1D< Real64 > DBySys; // Population Diversity by system
 	Array1D< std::string > PeakPsOccurrenceDateTimeStringBySys; // string describing when Ps peak occurs
 	Array1D< std::string > PeakPsOccurrenceEnvironmentStringBySys; // string describing Environment when Ps peak occurs
-	//Array1D< Real64 > PzSumBySysCool; // saved value of TotalPeople which is Pz-sum used in 62.1 tabular report
-	//Array1D< Real64 > PzSumBySysHeat; // saved value of TotalPeople which is Pz-sum used in 62.1 tabular report
-	//Array1D< Real64 > PsBySysCool; // saved value of PeakPeople which is Ps used in 62.1 tabular report
-	//Array1D< Real64 > PsBySysHeat; // saved value of PeakPeople which is Ps used in 62.1 tabular report
-	//Array1D< Real64 > DBySysCool; // saved value of PopulatonDiversity which is D used in 62.1 tabular report
-	//Array1D< Real64 > DBySysHeat; // saved value of PopulatonDiversity which is D used in 62.1 tabular report
 	Array1D< Real64 > VouBySys; // uncorrected system outdoor air requirement, for std 62.1 VRP
 	Array1D< Real64 > VpsClgBySys; // System primary airflow Vps, for cooling for std 62.1 VRP
 	Array1D< Real64 > VpsHtgBySys; // system primary airflow Vps, for heating for std 62.1 VRP
@@ -548,6 +542,66 @@ namespace DataSizing {
 		SensCoolCapTemp.deallocate();
 	}
 
+	Real64
+	TermUnitSizingData::applyTermUnitSizingCoolFlow(
+		Real64 const & coolFlowWithOA, // Cooling flow rate with MinOA limit applied
+		Real64 const & coolFlowNoOA // Cooling flow rate without MinOA limit applied
+	)
+	{
+		// Apply DesignSpecification:AirTerminal:Sizing to cooling flow (could be vol flow or mass flow)
+		Real64 coolFlowRatio = 1.0;
+		if ( this->SpecDesCoolSATRatio > 0.0 ) {
+			coolFlowRatio = this->SpecDesSensCoolingFrac / this->SpecDesCoolSATRatio;
+		} else {
+			coolFlowRatio = this->SpecDesSensCoolingFrac;
+		}
+		Real64 adjustedFlow = coolFlowNoOA * coolFlowRatio + ( coolFlowWithOA - coolFlowNoOA ) * this->SpecMinOAFrac;
+		return adjustedFlow;
+	}
+
+	Real64
+	TermUnitSizingData::applyTermUnitSizingHeatFlow(
+		Real64 const & heatFlowWithOA, // Heating flow rate with MinOA limit applied
+		Real64 const & heatFlowNoOA // Heating flow rate without MinOA limit applied
+	)
+	{
+		// Apply DesignSpecification:AirTerminal:Sizing to heating flow (could be vol flow or mass flow)
+		Real64 heatFlowRatio = 1.0;
+		if ( this->SpecDesHeatSATRatio > 0.0 ) {
+			heatFlowRatio = this->SpecDesSensHeatingFrac / this->SpecDesHeatSATRatio;
+		} else {
+			heatFlowRatio = this->SpecDesSensHeatingFrac;
+		}
+		Real64 adjustedFlow = heatFlowNoOA * heatFlowRatio + ( heatFlowWithOA - heatFlowNoOA ) * this->SpecMinOAFrac;
+		return adjustedFlow;
+	}
+
+	void
+	ZoneSizingData::scaleZoneCooling(
+		Real64 const ratio // Scaling ratio
+	)
+	{
+		// Apply scaling ratio to TermUnitFinalZoneSizing cooling flow and load
+		this->DesCoolVolFlow = this->DesCoolVolFlow * ratio;
+		this->DesCoolMassFlow = this->DesCoolMassFlow * ratio;
+		this->DesCoolLoad = this->DesCoolLoad * ratio;
+		this->CoolFlowSeq = this->CoolFlowSeq * ratio;
+		this->CoolLoadSeq = this->CoolLoadSeq * ratio;
+	}
+
+	void
+	ZoneSizingData::scaleZoneHeating(
+		Real64 const ratio // Scaling ratio
+	)
+	{
+		// Apply scaling ratio to TermUnitFinalZoneSizing heating flow and load
+		this->DesHeatVolFlow = this->DesHeatVolFlow * ratio;
+		this->DesHeatMassFlow = this->DesHeatMassFlow * ratio;
+		this->DesHeatLoad = this->DesHeatLoad * ratio;
+		this->HeatFlowSeq = this->HeatFlowSeq * ratio;
+		this->HeatLoadSeq = this->HeatLoadSeq * ratio;
+	}
+
 } // DataSizing
 
 } // EnergyPlus

src/EnergyPlus/DataSizing.hh

@@ -405,6 +405,7 @@ namespace DataSizing {
 	{
 		// Members
 		std::string ZoneName; // name of a zone
+		std::string ADUName; // Terminal Unit Name (air distribution unit or direct air unit) - only assigned for TermUnitFinalZoneSizing
 		std::string CoolDesDay; // name of a cooling design day
 		std::string HeatDesDay; // name of a heating design day
 		int ZnCoolDgnSAMethod; // choice of how to get zone cooling design air temperature;
@@ -452,10 +453,12 @@ namespace DataSizing {
 		Real64 DOASHighSetpoint; // Dedicated Outside Air High Setpoint for Design [C]
 		int ActualZoneNum; // index into the Zone data array (in DataHeatBalance)
 		Real64 DesHeatMassFlow; // zone design heating air mass flow rate [kg/s]
+		Real64 DesHeatMassFlowNoOA; // zone design heating air mass flow rate without applying MinOA as a limit [kg/s]
 		Real64 DesHeatOAFlowFrac; // zone design heating OA air volume fraction [-]
 		bool EMSOverrideDesHeatMassOn; // true if EMS is acting on this structure
 		Real64 EMSValueDesHeatMassFlow; // Value EMS directing to use for Design Heating air mass flow [kg/s]
 		Real64 DesCoolMassFlow; // zone design cooling air mass flow rate [kg/s]
+		Real64 DesCoolMassFlowNoOA; // zone design cooling air mass flow rate without applying MinOA as a limit [kg/s]
 		Real64 DesCoolOAFlowFrac; // zone design cooling OA air volume fraction [-]
 		bool EMSOverrideDesCoolMassOn; // true if EMS is acting on this structure
 		Real64 EMSValueDesCoolMassFlow; // Value EMS directing to use for Design Cooling air mass flow [kg/s]
@@ -470,10 +473,12 @@ namespace DataSizing {
 		Real64 DesHeatDens; // zone design heating air density [kg/m3]
 		Real64 DesCoolDens; // zone design cooling air density [kg/m3]
 		Real64 DesHeatVolFlow; // zone design heating air volume flow rate including sizing factor and scaled to match airflow sizing [m3/s]
+		Real64 DesHeatVolFlowNoOA; // zone design heating air volume flow rate including sizing factor and scaled to match airflow sizing without MinOA limit [m3/s]
 		Real64 NonAirSysDesHeatVolFlow; // base zone design heating air volume flow rate including sizing factor [m3/s]
 		bool EMSOverrideDesHeatVolOn; // true if EMS is acting on this structure
 		Real64 EMSValueDesHeatVolFlow; // Value EMS directing to use for Design Heating air volume flow [m3/s]
 		Real64 DesCoolVolFlow; // zone design cooling air volume flow rate [m3/s]
+		Real64 DesCoolVolFlowNoOA; // zone design cooling air volume flow rate without applying MinOA as a limit [m3/s]
 		Real64 NonAirSysDesCoolVolFlow; // base zone design cooling air volume flow rate including sizing factor [m3/s]
 		bool EMSOverrideDesCoolVolOn; // true if EMS is acting on this structure
 		Real64 EMSValueDesCoolVolFlow; // Value EMS directing to use for Design cooling air volume flow [m3/s]
@@ -526,10 +531,10 @@ namespace DataSizing {
 		//  DesCoolMinAirFlowPerArea
 		Real64 DesHeatMaxAirFlow2; // design heating maximum air flow rate [m3/s] derived from
 		//  DesHeatMaxAirFlowPerArea
-		Array1D< Real64 > HeatFlowSeq; // daily sequence of zone heating air mass flow rate
-		//  (zone time step)
-		Array1D< Real64 > CoolFlowSeq; // daily sequence of zone cooling air mass flow rate
-		//  (zone time step)
+		Array1D< Real64 > HeatFlowSeq; // daily sequence of zone heating air mass flow rate (zone time step) [kg/s]
+		Array1D< Real64 > HeatFlowSeqNoOA; // daily sequence of zone heating air mass flow rate (zone time step) without MinOA limit [kg/s]
+		Array1D< Real64 > CoolFlowSeq; // daily sequence of zone cooling air mass flow rate (zone time step) [kg/s]
+		Array1D< Real64 > CoolFlowSeqNoOA; // daily sequence of zone cooling air mass flow rate (zone time step) without MinOA limit [kg/s]
 		Array1D< Real64 > HeatLoadSeq; // daily sequence of zone heating load (zone time step)
 		Array1D< Real64 > CoolLoadSeq; // daily sequence of zone cooling load (zone time step)
 		Array1D< Real64 > HeatZoneTempSeq; // daily sequence of zone temperatures (heating, zone time step)
@@ -616,10 +621,12 @@ namespace DataSizing {
 			DOASHighSetpoint( 0.0 ),
 			ActualZoneNum( 0 ),
 			DesHeatMassFlow( 0.0 ),
+			DesHeatMassFlowNoOA( 0.0 ),
 			DesHeatOAFlowFrac( 0.0 ),
 			EMSOverrideDesHeatMassOn( false ),
 			EMSValueDesHeatMassFlow( 0.0 ),
 			DesCoolMassFlow( 0.0 ),
+			DesCoolMassFlowNoOA( 0.0 ),
 			DesCoolOAFlowFrac( 0.0 ),
 			EMSOverrideDesCoolMassOn( false ),
 			EMSValueDesCoolMassFlow( 0.0 ),
@@ -634,10 +641,12 @@ namespace DataSizing {
 			DesHeatDens( 0.0 ),
 			DesCoolDens( 0.0 ),
 			DesHeatVolFlow( 0.0 ),
+			DesHeatVolFlowNoOA( 0.0 ),
 			NonAirSysDesHeatVolFlow( 0.0 ),
 			EMSOverrideDesHeatVolOn( false ),
 			EMSValueDesHeatVolFlow( 0.0 ),
 			DesCoolVolFlow( 0.0 ),
+			DesCoolVolFlowNoOA( 0.0 ),
 			NonAirSysDesCoolVolFlow( 0.0 ),
 			EMSOverrideDesCoolVolOn( false ),
 			EMSValueDesCoolVolFlow( 0.0 ),
@@ -712,12 +721,22 @@ namespace DataSizing {
 			DOASTotCoolLoad( 0.0 )
 		{}
 
+		void
+		scaleZoneCooling(
+			Real64 const ratio // Scaling ratio
+		);
+		void
+		scaleZoneHeating(
+			Real64 const ratio // Scaling ratio
+		);
+
 	};
 
 	struct TermUnitSizingData
 	{
 		// Members
 		int CtrlZoneNum; // Controlled zone number (index to FinalZoneSizing, etc.)
+		std::string ADUName; // Terminal Unit Name (air distribution unit or direct air unit)
 		Real64 AirVolFlow; // design air vol flow rate for single duct terminal unit [m3/s]
 		Real64 MaxHWVolFlow; // design Hot Water vol flow for single duct terminal unit [m3/s]
 		Real64 MaxSTVolFlow; // design Steam vol flow rate for single duct terminal unit [m3/s]
@@ -756,6 +775,17 @@ namespace DataSizing {
 			SpecMinOAFrac ( 1.0 )
 		{}
 
+		Real64
+		applyTermUnitSizingCoolFlow(
+			Real64 const & coolFlowWithOA, // Cooling flow rate with MinOA limit applied
+			Real64 const & coolFlowNoOA // Cooling flow rate without MinOA limit applied
+		);
+
+		Real64
+		applyTermUnitSizingHeatFlow(
+			Real64 const & heatFlowWithOA, // Heating flow rate with MinOA limit applied
+			Real64 const & heatFlowNoOA // Heating flow rate without MinOA limit applied
+		);
 	};
 
 	struct ZoneEqSizingData // data saved from zone eq component sizing and passed to subcomponents
@@ -1430,12 +1460,6 @@ namespace DataSizing {
 	extern Array1D< std::string > PeakPsOccurrenceDateTimeStringBySys; // string describing date and time when Ps peak occurs
 	extern Array1D< std::string > PeakPsOccurrenceEnvironmentStringBySys; // string describing Environment when Ps peak occurs
 
-	//extern Array1D< Real64 > PzSumBySysCool; // saved value of TotalPeople which is Pz-sum used in 62.1 tabular report
-	//extern Array1D< Real64 > PzSumBySysHeat; // saved value of TotalPeople which is Pz-sum used in 62.1 tabular report
-	//extern Array1D< Real64 > PsBySysCool; // saved value of PeakPeople which is Ps used in 62.1 tabular report
-	//extern Array1D< Real64 > PsBySysHeat; // saved value of PeakPeople which is Ps used in 62.1 tabular report
-	//extern Array1D< Real64 > DBySysCool; // saved value of PopulatonDiversity which is D used in 62.1 tabular report
-	//extern Array1D< Real64 > DBySysHeat; // saved value of PopulatonDiversity which is D used in 62.1 tabular report
 	extern Array1D< Real64 > VouBySys; // uncorrected system outdoor air requirement, for std 62.1 VRP
 
 	extern Array1D< Real64 > VpsClgBySys; // System primary airflow Vps, for cooling for std 62.1 VRP

src/EnergyPlus/DirectAirManager.cc

@@ -343,10 +343,11 @@ namespace DirectAirManager {
 							DirectAir( DirectAirNum ).TermUnitSizingNum = thisZoneEqConfig.AirDistUnitCool( SupAirIn ).TermUnitSizingIndex;
 							DirectAir( DirectAirNum ).ZoneEqNum = CtrlZone;
 							DirectAir( DirectAirNum ).CtrlZoneInNodeIndex = SupAirIn;
+							{ auto & thisTermUnitSizingData( DataSizing::TermUnitSizing( DirectAir( DirectAirNum ).TermUnitSizingNum ) );
+							thisTermUnitSizingData.ADUName = DirectAir( DirectAirNum ).EquipID;
 							// Fill TermUnitSizing with specs from DesignSpecification:AirTerminal:Sizing if there is one attached to this terminal unit
 							if ( DirectAir( DirectAirNum ).AirTerminalSizingSpecIndex > 0 ) {
 								{ auto const & thisAirTermSizingSpec( DataSizing::AirTerminalSizingSpec( DirectAir( DirectAirNum ).AirTerminalSizingSpecIndex ) );
-								{ auto & thisTermUnitSizingData( DataSizing::TermUnitSizing( thisZoneEqConfig.AirDistUnitCool( SupAirIn ).TermUnitSizingIndex ) );
 								thisTermUnitSizingData.SpecDesCoolSATRatio = thisAirTermSizingSpec.DesCoolSATRatio;
 								thisTermUnitSizingData.SpecDesHeatSATRatio = thisAirTermSizingSpec.DesHeatSATRatio;
 								thisTermUnitSizingData.SpecDesSensCoolingFrac = thisAirTermSizingSpec.DesSensCoolingFrac;