Merge pull request #8850 from NREL/8776FanOnOffZeroFanPowerDuringCooling

On-Off Fan Showing Zero Fan Power During Cooling for Unitary Systems with Single Speed Cooling Coil
NREL · Jul 16, 2021 · f44c136 · f44c136
2 parents cdc3bf2 + f5061a9
commit f44c136
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Showing 3 changed files with 36 additions and 1 deletion.
diff --git a/src/EnergyPlus/UnitarySystem.cc b/src/EnergyPlus/UnitarySystem.cc
@@ -10253,7 +10253,7 @@ namespace UnitarySystems {
                 }
             } else { // IF(MultiOrVarSpeedCoolCoil(UnitarySysNum)) THEN
                 state.dataUnitarySystems->CompOnMassFlow = this->MaxCoolAirMassFlow;
-                state.dataUnitarySystems->CompOnFlowRatio = this->m_CoolingSpeedRatio;
+                state.dataUnitarySystems->CompOnFlowRatio = this->m_CoolingFanSpeedRatio;
                 if (this->m_FanOpMode == DataHVACGlobals::ContFanCycCoil) {
                     if (this->m_AirFlowControl == UseCompFlow::UseCompressorOnFlow) {
                         state.dataUnitarySystems->CompOffMassFlow = this->MaxCoolAirMassFlow;

diff --git a/testfiles/FurnaceWithDXSystem.idf b/testfiles/FurnaceWithDXSystem.idf
@@ -1368,6 +1368,8 @@
 
   Output:Variable,*,Unitary System Fan Part Load Ratio,timestep;
 
+  Output:Variable,*,Fan Electricity Rate,timestep; !- HVAC Average [W]
+
   Output:Variable,*,Zone Air System Sensible Heating Energy,timestep;
 
   Output:Variable,*,Zone Air System Sensible Cooling Energy,timestep;

diff --git a/tst/EnergyPlus/unit/UnitarySystem.unit.cc b/tst/EnergyPlus/unit/UnitarySystem.unit.cc
@@ -3735,6 +3735,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.5, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(1.0, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(1.0, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->HeatingLoad, PartLoadRatio);
     EXPECT_EQ(0.5, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3744,6 +3745,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.5, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(1.0, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(1.0, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->HeatingLoad, PartLoadRatio);
     EXPECT_EQ(0.5, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3768,11 +3770,13 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnFlowRatio);
 
     PartLoadRatio = 0.7;
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->HeatingLoad, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3816,6 +3820,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnMassFlow);
     EXPECT_EQ(0.0, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnFlowRatio);
 
     // cooling load at various speeds
     thisSys.m_HeatingSpeedNum = 0;
@@ -3825,6 +3830,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.6, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(1.2, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(1.2, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.m_HeatingSpeedNum = 0;
     thisSys.m_CoolingSpeedNum = 2;
@@ -3833,6 +3839,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.6, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.6, state->dataUnitarySystems->CompOnFlowRatio);
 
     // cycling fan mode should drop to 0 flow rate at speed = 1
     thisSys.m_HeatingSpeedNum = 0;
@@ -3844,6 +3851,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnMassFlow);
     EXPECT_EQ(0.0, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnFlowRatio);
 
     // constant fan mode should not drop to idle flow rate at speed = 1
     thisSys.m_FanOpMode = DataHVACGlobals::ContFanCycCoil;
@@ -3857,6 +3865,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnMassFlow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnFlowRatio);
 
     // no load condition (operates at idle speed)
     thisSys.m_HeatingSpeedNum = 0;
@@ -3868,6 +3877,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     EXPECT_EQ(0.2, state->dataUnitarySystems->CompOnMassFlow);
     EXPECT_EQ(0.2, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.2, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.2, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.m_MultiSpeedHeatingCoil = true;
     thisSys.m_HeatingSpeedNum = 1;
@@ -3877,6 +3887,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->HeatingLoad, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3888,6 +3899,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.25, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->HeatingLoad, PartLoadRatio);
     EXPECT_EQ(0.25, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3902,6 +3914,7 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->CoolingLoad, PartLoadRatio);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
@@ -3912,10 +3925,30 @@ TEST_F(EnergyPlusFixture, UnitarySystemModel_SetOnOffMassFlowRateTest)
     thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+    // EXPECT_EQ(0.3, state->dataUnitarySystems->CompOnFlowRatio);
 
     thisSys.setSpeedVariables(*state, state->dataUnitarySystems->CoolingLoad, PartLoadRatio);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateLow);
     EXPECT_EQ(0.3, state->dataHVACGlobal->MSHPMassFlowRateHigh);
+
+    // tests to make sure the proper speed ratio is used to set CompOnFlowRatio
+    thisSys.m_CoolingSpeedNum = 1;
+    thisSys.m_CoolingSpeedRatio = 0.0;
+    thisSys.m_CoolingFanSpeedRatio = 1.0;
+    thisSys.m_MultiOrVarSpeedCoolCoil = false;
+    state->dataUnitarySystems->HeatingLoad = false;
+    state->dataUnitarySystems->CoolingLoad = true;
+    thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
+    EXPECT_EQ(1.0, state->dataUnitarySystems->CompOnFlowRatio);
+
+    thisSys.m_CoolingSpeedNum = 1;
+    thisSys.m_CoolingSpeedRatio = 1.0;
+    thisSys.m_CoolingFanSpeedRatio = 0.5;
+    thisSys.m_MultiOrVarSpeedCoolCoil = false;
+    state->dataUnitarySystems->HeatingLoad = false;
+    state->dataUnitarySystems->CoolingLoad = true;
+    thisSys.setOnOffMassFlowRate(*state, OnOffAirFlowRatio, PartLoadRatio);
+    EXPECT_EQ(0.5, state->dataUnitarySystems->CompOnFlowRatio);
 }
 
 TEST_F(EnergyPlusFixture, UnitarySystemModel_ConfirmUnitarySystemSizingTest)