fix cooling with similar approach as heating

Author: yujiex

src/EnergyPlus/DXCoils.cc

@@ -234,7 +234,8 @@ void SimDXCoil(EnergyPlusData &state,
         CalcDXHeatingCoil(state, DXCoilNum, PartLoadRatio, FanOpMode, AirFlowRatio, MaxCap);
     } break;
     case CoilVRF_FluidTCtrl_Cooling: {
-        CalcVRFCoolingCoil_FluidTCtrl(state, DXCoilNum, CompressorOperation::On, FirstHVACIteration, PartLoadRatio, FanOpMode, CompCycRatio, _, _);
+        CalcVRFCoolingCoil_FluidTCtrl(
+            state, DXCoilNum, CompressorOperation::On, FirstHVACIteration, PartLoadRatio, FanOpMode, CompCycRatio, _, _, MaxCap);
     } break;
     case CoilVRF_FluidTCtrl_Heating: {
         CalcVRFHeatingCoil_FluidTCtrl(state, CompressorOp, DXCoilNum, PartLoadRatio, FanOpMode, _, MaxCap);
@@ -6962,7 +6963,7 @@ void InitDXCoil(EnergyPlusData &state, int const DXCoilNum) // number of the cur
             } else if (thisDXCoil.DXCoilType_Num == DataHVACGlobals::CoilVRF_Cooling) {
                 CalcVRFCoolingCoil(state, DXCoilNum, CompressorOperation::On, false, 1.0, 1.0, 1.0, _, _, _);
             } else if (thisDXCoil.DXCoilType_Num == DataHVACGlobals::CoilVRF_FluidTCtrl_Cooling) {
-                CalcVRFCoolingCoil_FluidTCtrl(state, DXCoilNum, CompressorOperation::On, false, 1.0, 1.0, 1.0, _, _);
+                CalcVRFCoolingCoil_FluidTCtrl(state, DXCoilNum, CompressorOperation::On, false, 1.0, 1.0, 1.0, _, _, _);
             }
 
             // coil outlets
@@ -16613,7 +16614,8 @@ void CalcVRFCoolingCoil_FluidTCtrl(EnergyPlusData &state,
                                    int const FanOpMode,                    // Allows parent object to control fan operation
                                    Real64 const CompCycRatio,              // cycling ratio of VRF condenser
                                    ObjexxFCL::Optional_int_const PerfMode, // Performance mode for MultiMode DX coil; Always 1 for other coil types
-                                   ObjexxFCL::Optional<Real64 const> OnOffAirFlowRatio // ratio of compressor on airflow to compressor off airflow
+                                   ObjexxFCL::Optional<Real64 const> OnOffAirFlowRatio, // ratio of compressor on airflow to compressor off airflow
+                                   ObjexxFCL::Optional<Real64 const> MaxCoolCap         // maximum allowed cooling capacity
 )
 {
     // SUBROUTINE INFORMATION:
@@ -16838,7 +16840,12 @@ void CalcVRFCoolingCoil_FluidTCtrl(EnergyPlusData &state,
             ShowFatalError(state, format("{} \"{}\" - Rated total cooling capacity is zero or less.", thisDXCoil.DXCoilType, thisDXCoil.Name));
         }
 
-        TotCap = thisDXCoil.RatedTotCap(Mode);
+        if (present(MaxCoolCap)) {
+            TotCap = min(MaxCoolCap, thisDXCoil.RatedTotCap(Mode));
+        } else {
+            TotCap = thisDXCoil.RatedTotCap(Mode);
+        }
+
         QCoilReq = -PartLoadRatio * TotCap;
         if (PartLoadRatio == 0.0) {
             AirMassFlowMin = state.dataHVACVarRefFlow->OACompOffMassFlow;

src/EnergyPlus/DXCoils.hh

@@ -881,7 +881,8 @@ namespace DXCoils {
                                   int const FanOpMode,                               // Allows parent object to control fan operation
                                   Real64 const CompCycRatio,                         // cycling ratio of VRF condenser
                                   ObjexxFCL::Optional_int_const PerfMode, // Performance mode for MultiMode DX coil; Always 1 for other coil types
-                                  ObjexxFCL::Optional<Real64 const> OnOffAirFlowRatio // ratio of compressor on airflow to compressor off airflow
+                                  ObjexxFCL::Optional<Real64 const> OnOffAirFlowRatio, // ratio of compressor on airflow to compressor off airflow
+                                  ObjexxFCL::Optional<Real64 const> MaxCoolCap         // maximum allowed cooling capacity
     );
 
     void

src/EnergyPlus/HVACVariableRefrigerantFlow.cc

@@ -11369,6 +11369,7 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
     Real64 T_comp_in;                // temperature of refrigerant at compressor inlet, after piping loss (c) [C]
     Real64 TU_HeatingLoad;           // Heating load from terminal units, excluding heating loss [W]
     Real64 TU_CoolingLoad;           // Cooling load from terminal units, excluding heating loss [W]
+    Real64 TU_CoolingLoad_actual;    // TU_CoolingLoad trimed to maximum system capacity[W]
     Real64 Tdischarge;               // VRF Compressor discharge refrigerant temperature [C]
     Real64 Tsuction;                 // VRF compressor suction refrigerant temperature [C]
     Real64 Tolerance;                // Tolerance for condensing temperature calculation [C]
@@ -11436,6 +11437,7 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
     }
     this->TUCoolingLoad = TU_CoolingLoad; // this is cooling coil load, not terminal unit load
     this->TUHeatingLoad = TU_HeatingLoad; // this is heating coil load, not terminal unit load
+    TU_CoolingLoad_actual = TU_CoolingLoad;
 
     // loop through TU's and calculate average inlet conditions for active coils
     for (NumTU = 1; NumTU <= NumTUInList; ++NumTU) {
@@ -11571,9 +11573,7 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
         if (Q_c_TU_PL > CompEvaporatingCAPSpdMax) {
             // Required load is beyond the max system capacity
 
-            Q_c_TU_PL = CompEvaporatingCAPSpdMax;
-            TU_CoolingLoad = CompEvaporatingCAPSpdMax;
-            this->TUCoolingLoad = TU_CoolingLoad;
+            TU_CoolingLoad_actual = min(TU_CoolingLoad, CompEvaporatingCAPSpdMax);
             RefTSat = GetSatTemperatureRefrig(state, this->RefrigerantName, max(min(Pevap, RefPHigh), RefPLow), RefrigerantIndex, RoutineName);
             h_IU_evap_out = GetSupHeatEnthalpyRefrig(state,
                                                      this->RefrigerantName,
@@ -11582,7 +11582,7 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
                                                      RefrigerantIndex,
                                                      RoutineName);
             SH_IU_merged = 3;
-            m_ref_IU_evap = TU_CoolingLoad / (h_IU_evap_out - h_IU_evap_in);
+            m_ref_IU_evap = TU_CoolingLoad_actual / (h_IU_evap_out - h_IU_evap_in);
 
         } else {
 
@@ -11734,12 +11734,12 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
             this->CoffEvapCap * this->RatedEvapCapacity *
             CurveValue(
                 state, this->OUCoolingCAPFT(NumOfCompSpdInput), Tdischarge, Tsuction); // Include the piping loss, at the highest compressor speed
-        this->PipingCorrectionCooling = TU_CoolingLoad / (TU_CoolingLoad + Pipe_Q_c);
+        this->PipingCorrectionCooling = TU_CoolingLoad_actual / (TU_CoolingLoad_actual + Pipe_Q_c);
         state.dataHVACVarRefFlow->MaxCoolingCapacity(VRFCond) = this->CoolingCapacity; // for report, maximum evaporating capacity of the system
 
         this->HeatingCapacity = 0.0;         // Include the piping loss
         this->PipingCorrectionHeating = 1.0; // 1 means no piping loss
-        state.dataHVACVarRefFlow->MaxHeatingCapacity(VRFCond) = 0.0;
+        state.dataHVACVarRefFlow->MaxHeatingCapacity(VRFCond) = 0.0; // yujie: might be wrong here too, should be MaxCap = 1e+20
 
         this->OUCondHeatRate = Q_h_OU;
         this->OUEvapHeatRate = 0;
@@ -11957,7 +11957,7 @@ void VRFCondenserEquipment::CalcVRFCondenser_FluidTCtrl(EnergyPlusData &state)
 
         this->CoolingCapacity = 0.0; // Include the piping loss
         this->PipingCorrectionCooling = 0.0;
-        state.dataHVACVarRefFlow->MaxCoolingCapacity(VRFCond) = 0.0; // for report
+        state.dataHVACVarRefFlow->MaxCoolingCapacity(VRFCond) = 0.0; // for report . yujie: might be wrong here too, should be MaxCap = 1e+20
 
         this->OUCondHeatRate = 0;
         this->OUEvapHeatRate = Q_c_OU;