Improved Support for Multi-speed Fans

idd/Energy+.idd.in

@@ -36447,10 +36447,18 @@ ZoneHVAC:WaterToAirHeatPump,
         \note Constant results in 100% water flow regardless of compressor PLR
         \note Cycling results in water flow that matches compressor PLR
         \note ConstantOnDemand results in 100% water flow whenever the coil is on, but is 0% whenever the coil has no load
-   A20; \field Design Specification ZoneHVAC Sizing Object Name
+   A20, \field Design Specification ZoneHVAC Sizing Object Name
         \note Enter the name of a DesignSpecificationZoneHVACSizing object.
         \type object-list
         \object-list DesignSpecificationZoneHVACSizingName
+   A21, \field Design Specification Multispeed Object Type
+        \type choice
+        \key UnitarySystemPerformance:Multispeed
+        \note Enter the type of performance specification object used to describe the multispeed coil or fan.
+   A22; \field Design Specification Multispeed Object Name
+        \type object-list
+        \object-list UnitarySystemPerformaceNames
+        \note Enter the name of the performance specification object used to describe the multispeed coil or fan.
 
 ZoneHVAC:Dehumidifier:DX,
         \memo This object calculates the performance of zone (room) air dehumidifiers.
@@ -42340,14 +42348,21 @@ ZoneHVAC:TerminalUnit:VariableRefrigerantFlow,
        \default 21.0
        \units C
        \note Supplemental heater will not operate when outdoor temperature exceeds this value.
-  A19; \field Controlling Zone or Thermostat Location
+  A19, \field Controlling Zone or Thermostat Location
        \type object-list
        \object-list ZoneNames
        \note Used only for AirloopHVAC equipment on a main branch and defines zone name where thermostat is located.
        \note Not required for zone equipment. Leave blank if terminal unit is used in AirLoopHVAC:OutdoorAirSystem:EquipmentList.
        \note Required when terminal unit is used on main AirloopHVAC branch and coils are not set point controlled.
        \note When terminal unit is used in air loop and is load controlled, this zone's thermostat will control operation.
-
+  A20, \field Design Specification Multispeed Object Type
+       \type choice
+       \key UnitarySystemPerformance:Multispeed
+       \note Enter the type of performance specification object used to describe the multispeed coil or fan.
+  A21; \field Design Specification Multispeed Object Name
+       \type object-list
+       \object-list UnitarySystemPerformaceNames
+       \note Enter the name of the performance specification object used to describe the multispeed coil or fan.
 
 \group Zone HVAC Radiative/Convective Units
 

src/EnergyPlus/HVACFan.cc

@@ -351,11 +351,11 @@ namespace HVACFan {
 
     FanSystem::FanSystem(EnergyPlusData &state, std::string const &objectName)
         : availSchedIndex(0), inletNodeNum(0), outletNodeNum(0), designAirVolFlowRate(0.0), speedControl(SpeedControlMethod::NotSet), deltaPress(0.0),
-          designElecPower(0.0), powerModFuncFlowFractionCurveIndex(0), AirLoopNum(0), AirPathFlag(false), fanIsSecondaryDriver(false),
+          designElecPower(0.0), powerModFuncFlowFractionCurveIndex(0), AirLoopNum(0), AirPathFlag(false), m_numSpeeds(0), fanIsSecondaryDriver(false),
           m_fanType_Num(0), m_designAirVolFlowRateWasAutosized(false), m_minPowerFlowFrac(0.0), m_motorEff(0.0), m_motorInAirFrac(0.0),
           m_designElecPowerWasAutosized(false), m_powerSizingMethod(PowerSizingMethod::Invalid), m_elecPowerPerFlowRate(0.0),
           m_elecPowerPerFlowRatePerPressure(0.0), m_fanTotalEff(0.0), m_nightVentPressureDelta(0.0), m_nightVentFlowFraction(0.0), m_zoneNum(0),
-          m_zoneRadFract(0.0), m_heatLossesDestination(ThermalLossDestination::Invalid), m_qdotConvZone(0.0), m_qdotRadZone(0.0), m_numSpeeds(0),
+          m_zoneRadFract(0.0), m_heatLossesDestination(ThermalLossDestination::Invalid), m_qdotConvZone(0.0), m_qdotRadZone(0.0),
           m_inletAirMassFlowRate(0.0), m_outletAirMassFlowRate(0.0), m_maxAirMassFlowRate(0.0), m_inletAirTemp(0.0), m_outletAirTemp(0.0),
           m_inletAirHumRat(0.0), m_outletAirHumRat(0.0), m_inletAirEnthalpy(0.0), m_outletAirEnthalpy(0.0), m_objEnvrnFlag(true),
           m_objSizingFlag(true), m_fanPower(0.0), m_fanEnergy(0.0), m_maxAirFlowRateEMSOverrideOn(false), m_maxAirFlowRateEMSOverrideValue(0.0),

src/EnergyPlus/HVACFan.hh

@@ -140,6 +140,8 @@ namespace HVACFan {
         int powerModFuncFlowFractionCurveIndex; // pointer to performance curve or table
         int AirLoopNum;                         // AirLoop number
         bool AirPathFlag;                       // Yes, this fan is a part of airpath
+        int m_numSpeeds;                        // input for how many speed levels for discrete fan
+        std::vector<Real64> m_massFlowAtSpeed;
 
         // Mass Flow Rate Control Variables
         bool fanIsSecondaryDriver; // true if this fan is used to augment flow and may pass air when off.
@@ -205,12 +207,10 @@ namespace HVACFan {
         Real64 m_qdotConvZone;                          // fan power lost to surrounding zone by convection to air (W)
         Real64 m_qdotRadZone;                           // fan power lost to surrounding zone by radiation to zone surfaces(W)
         std::string m_endUseSubcategoryName;
-        int m_numSpeeds;                            // input for how many speed levels for discrete fan
         std::vector<Real64> m_flowFractionAtSpeed;  // array of flow fractions for speed levels
         std::vector<Real64> m_powerFractionAtSpeed; // array of power fractions for speed levels
         std::vector<bool> m_powerFractionInputAtSpeed;
         // calculation variables
-        std::vector<Real64> m_massFlowAtSpeed;
         std::vector<Real64> m_totEfficAtSpeed;
         Real64 m_inletAirMassFlowRate; // MassFlow through the Fan being Simulated [kg/Sec]
         Real64 m_outletAirMassFlowRate;