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Fix chiller chilling when it is off #10793

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Merged
Myoldmopar merged 13 commits into from
Dec 4, 2024
Merged

Fix chiller chilling when it is off #10793

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0e0005b
Warn if chiller chills when off
mjwitte Oct 17, 2024
e827c62
Warn if chiller chills when off
mjwitte Oct 17, 2024
394a2c7
Fix chiller off when condenser flow is zero
mjwitte Oct 17, 2024
172283a
Revert Warn if chiller chills when off
mjwitte Oct 18, 2024
c894587
Fix chiller off when condenser flow is zero for all other chillers
mjwitte Oct 29, 2024
85be6e1
Merge remote-tracking branch 'remotes/origin/develop' into chillerEIR…
mjwitte Nov 13, 2024
ba3f01d
Merge remote-tracking branch 'remotes/origin/develop' into chillerEIR…
mjwitte Nov 15, 2024
a87f0ad
Extend EIR chiller unit test
mjwitte Nov 15, 2024
dfcd0c1
Set evapmassflow to zero
mjwitte Nov 15, 2024
4f9f8b1
Merge remote-tracking branch 'remotes/origin/develop' into chillerEIR…
mjwitte Nov 18, 2024
7d3063a
Set evapmassflow to zero
mjwitte Nov 18, 2024
1ecc79e
undo VS formatting
mjwitte Nov 18, 2024
bbcd4ce
Merge remote-tracking branch 'remotes/origin/develop' into chillerEIR…
mjwitte Nov 22, 2024
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1 change: 1 addition & 0 deletions src/EnergyPlus/ChillerAbsorption.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1728,6 +1728,7 @@ void BLASTAbsorberSpecs::calculate(EnergyPlusData &state, Real64 &MyLoad, bool R
this->CondOutletTemp = state.dataLoopNodes->Node(this->CondInletNodeNum).Temp;
this->CondMassFlowRate = 0.0;
this->QCondenser = 0.0;
MyLoad = 0.0;
return;
// V7 plant upgrade, no longer fatal here anymore, set some things and return
}
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7 changes: 6 additions & 1 deletion src/EnergyPlus/ChillerElectricASHRAE205.cc
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Expand Up @@ -1337,7 +1337,12 @@ void ASHRAE205ChillerSpecs::calculate(EnergyPlusData &state, Real64 &MyLoad, boo
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);

if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
this->Power = standbyPower;
this->AmbientZoneGain = standbyPower;
return;
}
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@Myoldmopar Myoldmopar Dec 4, 2024

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Looks right.

}
Real64 EvapOutletTempSetPoint(0.0); // Evaporator outlet temperature setpoint [C]
switch (state.dataPlnt->PlantLoop(PlantLoopNum).LoopDemandCalcScheme) {
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10 changes: 5 additions & 5 deletions src/EnergyPlus/ChillerElectricEIR.cc
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Expand Up @@ -1962,11 +1962,11 @@ void ElectricEIRChillerSpecs::calculate(EnergyPlusData &state, Real64 &MyLoad, b
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);

if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
if (this->EvapMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
// Use PlantUtilities::SetComponentFlowRate to decide actual flow
PlantUtilities::SetComponentFlowRate(
state, this->EvapMassFlowRate, this->EvapInletNodeNum, this->EvapOutletNodeNum, this->CWPlantLoc);
}
// Shut chiller off if there is no condenser water flow
MyLoad = 0.0;
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@rraustad rraustad Oct 19, 2024 •
edited
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This does look like it boils down to this. I looked at PullCompInterconnectTrigger to see what that was trying to accomplish. This code looks like it can be deleted. I'm not asking for that to happen here but it's extra clock cycles. Removed in #10794,

    // Check to make sure we didn't reuse the index in multiple components
    if (CurCriteria.CallingCompLoopNum != plantLoc.loopNum || CurCriteria.CallingCompLoopSideNum != plantLoc.loopSideNum ||
        CurCriteria.CallingCompBranchNum != plantLoc.branchNum || CurCriteria.CallingCompCompNum != plantLoc.compNum) {
        // Diagnostic fatal: component does not properly utilize unique indexing
    }

this->EvapMassFlowRate = 0.0;
// Use PlantUtilities::SetComponentFlowRate to decide actual flow
PlantUtilities::SetComponentFlowRate(state, this->EvapMassFlowRate, this->EvapInletNodeNum, this->EvapOutletNodeNum, this->CWPlantLoc);
return;
}
}
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3 changes: 2 additions & 1 deletion src/EnergyPlus/ChillerIndirectAbsorption.cc
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Expand Up @@ -1604,7 +1604,7 @@ void IndirectAbsorberSpecs::sizeChiller(EnergyPlusData &state)
}
}

void IndirectAbsorberSpecs::calculate(EnergyPlusData &state, Real64 const MyLoad, bool const RunFlag)
void IndirectAbsorberSpecs::calculate(EnergyPlusData &state, Real64 MyLoad, bool const RunFlag)
{
// SUBROUTINE INFORMATION:
// AUTHOR R. Raustad (FSEC)
Expand Down Expand Up @@ -1999,6 +1999,7 @@ void IndirectAbsorberSpecs::calculate(EnergyPlusData &state, Real64 const MyLoad
this->CondOutletTemp = CondInletTemp;
this->CondMassFlowRate = 0.0;
this->QCondenser = 0.0;
MyLoad = 0.0;
return;
// V7 plant upgrade, no longer fatal here anymore... set some things and return
}
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5 changes: 4 additions & 1 deletion src/EnergyPlus/ChillerReformulatedEIR.cc
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Expand Up @@ -2147,7 +2147,10 @@ void ReformulatedEIRChillerSpecs::calculate(EnergyPlusData &state, Real64 &MyLoa
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);

if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
return;
}
}
Real64 FRAC = 1.0;
Real64 EvapOutletTempSetPoint(0.0); // Evaporator outlet temperature setpoint [C]
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20 changes: 16 additions & 4 deletions src/EnergyPlus/PlantChillers.cc
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Expand Up @@ -1468,7 +1468,10 @@ namespace PlantChillers {
PlantUtilities::SetComponentFlowRate(state, this->CondMassFlowRate, this->CondInletNodeNum, this->CondOutletNodeNum, this->CDPlantLoc);
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
return;
}
}

// LOAD LOCAL VARIABLES FROM DATA STRUCTURE (for code readability)
Expand Down Expand Up @@ -3593,7 +3596,10 @@ namespace PlantChillers {
PlantUtilities::SetComponentFlowRate(state, this->CondMassFlowRate, this->CondInletNodeNum, this->CondOutletNodeNum, this->CDPlantLoc);
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
return;
}
}

// LOAD LOCAL VARIABLES FROM DATA STRUCTURE (for code readability)
Expand Down Expand Up @@ -5605,7 +5611,10 @@ namespace PlantChillers {
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);

if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
return;
}
}

// LOAD LOCAL VARIABLES FROM DATA STRUCTURE (for code readability)
Expand Down Expand Up @@ -7313,7 +7322,10 @@ namespace PlantChillers {
PlantUtilities::PullCompInterconnectTrigger(
state, this->CWPlantLoc, this->CondMassFlowIndex, this->CDPlantLoc, DataPlant::CriteriaType::MassFlowRate, this->CondMassFlowRate);

if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) return;
if (this->CondMassFlowRate < DataBranchAirLoopPlant::MassFlowTolerance) {
MyLoad = 0.0;
return;
}
}

// If FlowLock is True, the new resolved mdot is used to update Power, QEvap, Qcond, and
Expand Down
41 changes: 37 additions & 4 deletions tst/EnergyPlus/unit/ChillerElectricEIR.unit.cc
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Expand Up @@ -563,13 +563,46 @@ TEST_F(EnergyPlusFixture, ChillerElectricEIR_WaterCooledChillerVariableSpeedCond
Real64 ActualCondFlow = 3.0 * std::abs(MyLoad) / (Cp * 10.0);
EXPECT_NEAR(thisChiller.CondMassFlowRate, ActualCondFlow, 0.00001);

thisChiller.CondenserFlowControl = DataPlant::CondenserFlowControl::ConstantFlow;
thisChiller.calculate(*state, MyLoad, RunFlag);
EXPECT_NEAR(thisChiller.CondMassFlowRate, thisChiller.CondMassFlowRateMax, 0.00001);

// Test the minimum condenser flow rate
MyLoad = -500;
thisChiller.CondenserFlowControl = DataPlant::CondenserFlowControl::ModulatedChillerPLR;
thisChiller.calculate(*state, MyLoad, RunFlag);
EXPECT_NEAR(thisChiller.CondMassFlowRate, thisChiller.CondMassFlowRateMax * 0.35, 0.00001);

// Test constant flow condenser
thisChiller.CondenserFlowControl = DataPlant::CondenserFlowControl::ConstantFlow;
MyLoad = -10000;
Real64 savedMyLoad = MyLoad;

// test with condenser flow available
thisChiller.initialize(*state, RunFlag, MyLoad);
thisChiller.calculate(*state, MyLoad, RunFlag);
thisChiller.update(*state, MyLoad, RunFlag);
Real64 chWOutletTemp = thisChiller.EvapInletTemp + savedMyLoad / (Cp * thisChiller.EvapMassFlowRate);
Real64 condOutletTemp = thisChiller.CondInletTemp + thisChiller.QCondenser / (Cp * thisChiller.CondMassFlowRate);
EXPECT_EQ(MyLoad, savedMyLoad);
EXPECT_NEAR(thisChiller.CondMassFlowRate, thisChiller.CondMassFlowRateMax, 0.00001);
EXPECT_NEAR(thisChiller.EvapMassFlowRate, thisChiller.EvapMassFlowRateMax, 0.00001);
EXPECT_NEAR(thisChiller.EvapOutletTemp, chWOutletTemp, 0.1);
EXPECT_NEAR(thisChiller.CondOutletTemp, condOutletTemp, 0.1);
EXPECT_NEAR(thisChiller.QEvaporator, -savedMyLoad, 1.0);
EXPECT_NEAR(thisChiller.QCondenser, (-savedMyLoad + thisChiller.Power), 1.0);
EXPECT_NEAR(thisChiller.Power, 20987, 1.0);

// test with no condenser flow available - chiller should be off
state->dataLoopNodes->Node(thisChiller.CondInletNodeNum).MassFlowRate = 0.0;
state->dataLoopNodes->Node(thisChiller.CondInletNodeNum).MassFlowRateMaxAvail = 0.0;
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@rraustad rraustad Nov 18, 2024

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MaxAvail does need to be set to 0 here, at the inlet node, but I wonder why. It's a limit. If the chiller requests 0 then it should set to 0 if not in series with another component? FlowCtrl = Invalid in this unit test so it's not series active. I tested this unit test both ways, with this line commented out and with the MaxAvail = 1. It failed both times. I guess the plant manager will set MaxAvail as necessary, at the condenser inlet, and this line is needed for that reason. The chiller can be off and still have flow at the condenser and/or evaporator if the plant requests it (e.g., no bypass loop).

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@mjwitte mjwitte Nov 18, 2024

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I just wanted to be sure the chiller saw that there was no condenser flow. Anyways, the extended unit test fails with develop. I'm going to add the evap mass flow = 0 change now to the other chiller types.

thisChiller.initialize(*state, RunFlag, MyLoad);
thisChiller.calculate(*state, MyLoad, RunFlag);
thisChiller.update(*state, MyLoad, RunFlag);
EXPECT_EQ(MyLoad, 0.0);
EXPECT_EQ(thisChiller.CondMassFlowRate, 0.0);
EXPECT_EQ(thisChiller.EvapMassFlowRate, 0.0);
EXPECT_EQ(thisChiller.EvapOutletTemp, thisChiller.EvapInletTemp);
EXPECT_EQ(thisChiller.CondOutletTemp, thisChiller.CondInletTemp);
EXPECT_EQ(thisChiller.QEvaporator, 0.0);
EXPECT_EQ(thisChiller.QCondenser, 0.0);
EXPECT_EQ(thisChiller.Power, 0.0);

// Test
}