Fix timed defrost.

NREL · Dec 14, 2023 · 43dfa02 · 43dfa02
1 parent 4ccd87a
commit 43dfa02
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Showing 2 changed files with 18 additions and 10 deletions.
diff --git a/src/EnergyPlus/DXCoils.cc b/src/EnergyPlus/DXCoils.cc
@@ -11174,10 +11174,8 @@ void CalcDXHeatingCoil(EnergyPlusData &state,
             // Calculate defrost adjustment factors depending on defrost control type
             if (thisDXCoil.DefrostControl == StandardRatings::HPdefrostControl::Timed) {
                 FractionalDefrostTime = thisDXCoil.DefrostTime;
-                if (FractionalDefrostTime > 0.0) {
-                    HeatingCapacityMultiplier = 0.909 - 107.33 * OutdoorCoildw;
-                    InputPowerMultiplier = 0.90 - 36.45 * OutdoorCoildw;
-                }
+                HeatingCapacityMultiplier = 0.909 - 107.33 * OutdoorCoildw;
+                InputPowerMultiplier = 0.90 - 36.45 * OutdoorCoildw;
             } else { // else defrost control is on-demand
                 FractionalDefrostTime = 1.0 / (1.0 + 0.01446 / OutdoorCoildw);
                 HeatingCapacityMultiplier = 0.875 * (1.0 - FractionalDefrostTime);
@@ -13796,7 +13794,7 @@ void CalcMultiSpeedDXCoilHeating(EnergyPlusData &state,
             DefrostPowerLS = 0.0;
             DefrostPowerHS = 0.0;
 
-            // Check outdoor temperature to determine of defrost is active
+            // Check outdoor temperature to determine if defrost is active
             if (OutdoorDryBulb <= thisDXCoil.MaxOATDefrost) {
                 // Calculate defrost adjustment factors depending on defrost control type
                 if (thisDXCoil.DefrostControl == StandardRatings::HPdefrostControl::Timed) {
@@ -13829,6 +13827,12 @@ void CalcMultiSpeedDXCoilHeating(EnergyPlusData &state,
                 }
             }
 
+            // Make no adjustment if there is no defrost power available
+            if (thisDXCoil.DefrostPower == 0.0) {
+                HeatingCapacityMultiplier = 1.0;
+                InputPowerMultiplier = 1.0;
+            }
+
             TotCapLSAdj = TotCapLS * HeatingCapacityMultiplier;
             TotCapHSAdj = TotCapHS * HeatingCapacityMultiplier;
 
@@ -14039,6 +14043,12 @@ void CalcMultiSpeedDXCoilHeating(EnergyPlusData &state,
                 }
             }
 
+            // Make no adjustment if there is no defrost power available
+            if (thisDXCoil.DefrostPower == 0.0) {
+                HeatingCapacityMultiplier = 1.0;
+                InputPowerMultiplier = 1.0;
+            }
+
             // Modify total heating capacity based on defrost heating capacity multiplier
             TotCapAdj = TotCap * HeatingCapacityMultiplier;
 

diff --git a/src/EnergyPlus/HVACVariableRefrigerantFlow.cc b/src/EnergyPlus/HVACVariableRefrigerantFlow.cc
@@ -870,10 +870,8 @@ void CalcVRFCondenser(EnergyPlusData &state, int const VRFCond)
             // Calculate defrost adjustment factors depending on defrost control type
             if (vrf.DefrostControl == StandardRatings::HPdefrostControl::Timed) {
                 FractionalDefrostTime = vrf.DefrostFraction;
-                if (FractionalDefrostTime > 0.0) {
-                    HeatingCapacityMultiplier = 0.909 - 107.33 * OutdoorCoildw;
-                    InputPowerMultiplier = 0.90 - 36.45 * OutdoorCoildw;
-                }
+                HeatingCapacityMultiplier = 0.909 - 107.33 * OutdoorCoildw;
+                InputPowerMultiplier = 0.90 - 36.45 * OutdoorCoildw;
             } else { // else defrost control is on-demand
                 FractionalDefrostTime = 1.0 / (1.0 + 0.01446 / OutdoorCoildw);
                 HeatingCapacityMultiplier = 0.875 * (1.0 - FractionalDefrostTime);
@@ -916,7 +914,7 @@ void CalcVRFCondenser(EnergyPlusData &state, int const VRFCond)
 
                     vrf.DefrostPower = DefrostEIRTempModFac * (vrf.HeatingCapacity / 1.01667) * FractionalDefrostTime;
 
-                } else { // Defrost strategy is resistive
+                } else { // Defrost strategy is resistive   
                     vrf.DefrostPower = vrf.DefrostCapacity * FractionalDefrostTime;
                 }
             }