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Variable speed coils can have higher flow rate than Packaged Terminal unit and fan #5723

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merged 17 commits into from
Aug 18, 2017
Merged

Variable speed coils can have higher flow rate than Packaged Terminal unit and fan #5723

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23a947e
Fix PTHP air flow to use actual flow rate instead of rated flow rate.
nealkruis May 19, 2016
3eae46a
Fix central fan mass conservation issue.
nealkruis May 20, 2016
3d49396
Move mass balance check.
nealkruis May 26, 2016
5974721
Merge develop into conservation-tests.
nealkruis Jun 10, 2016
51bdf29
Move VS airflow fix to an earlier section of code so that intermediat…
nealkruis Jun 10, 2016
a15ee9b
Merge branch 'develop' of https://github.com/NREL/EnergyPlus into con…
rraustad Jun 11, 2016
843e540
Merge branch 'conservation-tests' of https://github.com/NREL/EnergyPl…
rraustad Jun 11, 2016
9df86cd
Moved VS coil air flow init inside sizing IF
rraustad Jun 11, 2016
6ee58f2
Merge branch 'develop' into conservation-tests
rraustad Jul 8, 2016
403c8d2
Convert conservation warnings to RecurringAtEnd. Also not sure if PTH…
rraustad Jul 8, 2016
370a6a8
Correct cut-n-paste error with variable name
rraustad Jul 8, 2016
cadebde
Initialize warning counter variables
rraustad Jul 9, 2016
7f0bb5e
Merge branch 'develop' of https://github.com/NREL/EnergyPlus into con…
rraustad Jul 11, 2016
9e0edee
Delete mass conservation warnings
rraustad Jul 12, 2016
3f38b97
Merge branch 'develop' of https://github.com/NREL/EnergyPlus into con…
rraustad Jul 12, 2016
44599a8
Modified unit test to include air flow tests for VS coil
rraustad Jul 14, 2016
2c8016c
Merge branch 'develop' of https://github.com/NREL/EnergyPlus into con…
rraustad Aug 12, 2017
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73 changes: 36 additions & 37 deletions src/EnergyPlus/PackagedTerminalHeatPump.cc
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Expand Up @@ -3012,7 +3012,6 @@ namespace PackagedTerminalHeatPump {
int i; // Loop index
int Iter; // speed iteration count
int PTObjectIndex;
Real64 MulSpeedFlowScale; // variable speed air flow scaling factor
int CtrlZoneNum; // the controlled zone index (index of ZoneEquipConfig)

InNode = PTUnit( PTUnitNum ).AirInNode;
Expand Down Expand Up @@ -3141,49 +3140,51 @@ namespace PackagedTerminalHeatPump {
if ( ! SysSizingCalc && MySizeFlag( PTUnitNum ) ) {
SizePTUnit( PTUnitNum );
MySizeFlag( PTUnitNum ) = false;
}

if ( PTUnit( PTUnitNum ).useVSCoilModel && PTUnit( PTUnitNum ).NumOfSpeedCooling == 0 && ! MySizeFlag( PTUnitNum ) ) {
RhoAir = StdRhoAir;
PTUnit( PTUnitNum ).MaxCoolAirMassFlow = RhoAir * PTUnit( PTUnitNum ).MaxCoolAirVolFlow;
PTUnit( PTUnitNum ).MaxHeatAirMassFlow = RhoAir * PTUnit( PTUnitNum ).MaxHeatAirVolFlow;

if ( PTUnit( PTUnitNum ).useVSCoilModel && PTUnit( PTUnitNum ).NumOfSpeedCooling == 0 ) {
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So what is "PTUnit( PTUnitNum ).NumOfSpeedCooling == 0" supposed to mean here?

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@rraustad rraustad Jun 11, 2016 •
edited
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It must be NumOfSpeedCooling > 0 for multispeed, and = 0 for VS? Or that the speed variables have not be calculated yet?

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Good question. This was already here when I found it. @EnergyArchmage?

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yes, it is NumOfSpeedCooling > 0 for multispeed, and = 0 for VS. I think these have been moving to use the bool over time, moving away from == 0 for VS, but it still lingers.


SimVariableSpeedCoils( "", PTUnit( PTUnitNum ).DXCoolCoilIndexNum, 0, PTUnit( PTUnitNum ).MaxONOFFCyclesperHour, PTUnit( PTUnitNum ).HPTimeConstant, PTUnit( PTUnitNum ).FanDelayTime, 0, 0.0, 1, 0.0, 0.0, 0.0, 0.0 ); //conduct the sizing operation in the VS WSHP
PTUnit( PTUnitNum ).NumOfSpeedCooling = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).NumOfSpeeds;
SimVariableSpeedCoils( "", PTUnit( PTUnitNum ).DXCoolCoilIndexNum, 0, PTUnit( PTUnitNum ).MaxONOFFCyclesperHour, PTUnit( PTUnitNum ).HPTimeConstant, PTUnit( PTUnitNum ).FanDelayTime, 0, 0.0, 1, 0.0, 0.0, 0.0, 0.0 ); //conduct the sizing operation in the VS WSHP
PTUnit( PTUnitNum ).NumOfSpeedCooling = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).NumOfSpeeds;
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@rraustad rraustad Jul 18, 2016 •
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This ratio was originally used to scale the rated air flow rate to the "nominal" design air flow rate using VarSpeedCoil.NormSpedLevel . This ratio has been removed below and I don't think this is correct now (assumes nominal speed is always equal to max speed). From the IO Ref:

1.40.33.1.7 Field: Nominal Speed Level
This numeric field defines the nominal speed level, at which the rated capacity, rated air and
water volumetric flow rates are correlated.


MulSpeedFlowScale = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).RatedAirVolFlowRate / VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).NormSpedLevel );
for ( Iter = 1; Iter <= PTUnit( PTUnitNum ).NumOfSpeedCooling; ++Iter ) {
PTUnit( PTUnitNum ).CoolVolumeFlowRate( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) * MulSpeedFlowScale;
PTUnit( PTUnitNum ).CoolMassFlowRate( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirMassFlowRate( Iter ) * MulSpeedFlowScale;
PTUnit( PTUnitNum ).MSCoolingSpeedRatio( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) / VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( PTUnit( PTUnitNum ).NumOfSpeedCooling );
}
for ( Iter = 1; Iter <= PTUnit( PTUnitNum ).NumOfSpeedCooling; ++Iter ) {
PTUnit( PTUnitNum ).MSCoolingSpeedRatio( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) / VarSpeedCoil( PTUnit( PTUnitNum ).DXCoolCoilIndexNum ).MSRatedAirVolFlowRate( PTUnit( PTUnitNum ).NumOfSpeedCooling );
PTUnit( PTUnitNum ).CoolVolumeFlowRate( Iter ) = PTUnit( PTUnitNum ).MaxCoolAirVolFlow * PTUnit( PTUnitNum ).MSCoolingSpeedRatio( Iter );
PTUnit( PTUnitNum ).CoolMassFlowRate( Iter ) = PTUnit( PTUnitNum ).MaxCoolAirMassFlow * PTUnit( PTUnitNum ).MSCoolingSpeedRatio( Iter );
}

if ( PTUnit( PTUnitNum ).DXHeatCoilType_Num == Coil_HeatingWaterToAirHPVSEquationFit || PTUnit( PTUnitNum ).DXHeatCoilType_Num == Coil_HeatingAirToAirVariableSpeed ) {
if ( PTUnit( PTUnitNum ).DXHeatCoilType_Num == Coil_HeatingWaterToAirHPVSEquationFit || PTUnit( PTUnitNum ).DXHeatCoilType_Num == Coil_HeatingAirToAirVariableSpeed ) {

SimVariableSpeedCoils( "", PTUnit( PTUnitNum ).DXHeatCoilIndexNum, 0, PTUnit( PTUnitNum ).MaxONOFFCyclesperHour, PTUnit( PTUnitNum ).HPTimeConstant, PTUnit( PTUnitNum ).FanDelayTime, 0, 0.0, 1, 0.0, 0.0, 0.0, 0.0 ); //conduct the sizing operation in the VS WSHP
SimVariableSpeedCoils( "", PTUnit( PTUnitNum ).DXHeatCoilIndexNum, 0, PTUnit( PTUnitNum ).MaxONOFFCyclesperHour, PTUnit( PTUnitNum ).HPTimeConstant, PTUnit( PTUnitNum ).FanDelayTime, 0, 0.0, 1, 0.0, 0.0, 0.0, 0.0 ); //conduct the sizing operation in the VS WSHP

PTUnit( PTUnitNum ).NumOfSpeedHeating = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).NumOfSpeeds;
PTUnit( PTUnitNum ).NumOfSpeedHeating = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).NumOfSpeeds;

MulSpeedFlowScale = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).RatedAirVolFlowRate / VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).NormSpedLevel );
for ( Iter = 1; Iter <= PTUnit( PTUnitNum ).NumOfSpeedHeating; ++Iter ) {
PTUnit( PTUnitNum ).HeatVolumeFlowRate( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) * MulSpeedFlowScale;
PTUnit( PTUnitNum ).HeatMassFlowRate( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirMassFlowRate( Iter ) * MulSpeedFlowScale;
PTUnit( PTUnitNum ).MSHeatingSpeedRatio( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) / VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( PTUnit( PTUnitNum ).NumOfSpeedHeating );
for ( Iter = 1; Iter <= PTUnit( PTUnitNum ).NumOfSpeedHeating; ++Iter ) {
PTUnit( PTUnitNum ).MSHeatingSpeedRatio( Iter ) = VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( Iter ) / VarSpeedCoil( PTUnit( PTUnitNum ).DXHeatCoilIndexNum ).MSRatedAirVolFlowRate( PTUnit( PTUnitNum ).NumOfSpeedHeating );
PTUnit( PTUnitNum ).HeatVolumeFlowRate( Iter ) = PTUnit( PTUnitNum ).MaxHeatAirVolFlow * PTUnit( PTUnitNum ).MSHeatingSpeedRatio( Iter );
PTUnit( PTUnitNum ).HeatMassFlowRate( Iter ) = PTUnit( PTUnitNum ).MaxHeatAirMassFlow * PTUnit( PTUnitNum ).MSHeatingSpeedRatio( Iter );
}
}
}
// intialize idle flow
// intialize idle flow

if ( PTUnit( PTUnitNum ).NumOfSpeedHeating > 0 ) {
PTUnit( PTUnitNum ).IdleMassFlowRate = min( PTUnit( PTUnitNum ).HeatMassFlowRate( 1 ), PTUnit( PTUnitNum ).CoolMassFlowRate( 1 ) );
PTUnit( PTUnitNum ).IdleSpeedRatio = min( PTUnit( PTUnitNum ).MSHeatingSpeedRatio( 1 ), PTUnit( PTUnitNum ).MSCoolingSpeedRatio( 1 ) );
PTUnit( PTUnitNum ).IdleVolumeAirRate = min( PTUnit( PTUnitNum ).HeatVolumeFlowRate( 1 ), PTUnit( PTUnitNum ).CoolVolumeFlowRate( 1 ) );
} else {
PTUnit( PTUnitNum ).IdleMassFlowRate = PTUnit( PTUnitNum ).CoolMassFlowRate( 1 );
PTUnit( PTUnitNum ).IdleSpeedRatio = PTUnit( PTUnitNum ).MSCoolingSpeedRatio( 1 );
PTUnit( PTUnitNum ).IdleVolumeAirRate = PTUnit( PTUnitNum ).CoolVolumeFlowRate( 1 );
}
if ( PTUnit( PTUnitNum ).NumOfSpeedHeating > 0 ) {
PTUnit( PTUnitNum ).IdleMassFlowRate = min( PTUnit( PTUnitNum ).HeatMassFlowRate( 1 ), PTUnit( PTUnitNum ).CoolMassFlowRate( 1 ) );
PTUnit( PTUnitNum ).IdleSpeedRatio = min( PTUnit( PTUnitNum ).MSHeatingSpeedRatio( 1 ), PTUnit( PTUnitNum ).MSCoolingSpeedRatio( 1 ) );
PTUnit( PTUnitNum ).IdleVolumeAirRate = min( PTUnit( PTUnitNum ).HeatVolumeFlowRate( 1 ), PTUnit( PTUnitNum ).CoolVolumeFlowRate( 1 ) );
} else {
PTUnit( PTUnitNum ).IdleMassFlowRate = PTUnit( PTUnitNum ).CoolMassFlowRate( 1 );
PTUnit( PTUnitNum ).IdleSpeedRatio = PTUnit( PTUnitNum ).MSCoolingSpeedRatio( 1 );
PTUnit( PTUnitNum ).IdleVolumeAirRate = PTUnit( PTUnitNum ).CoolVolumeFlowRate( 1 );
}

if ( PTUnit( PTUnitNum ).OpMode == ContFanCycCoil ) {
PTUnit( PTUnitNum ).MaxNoCoolHeatAirVolFlow = PTUnit( PTUnitNum ).IdleVolumeAirRate;
PTUnit( PTUnitNum ).MaxNoCoolHeatAirMassFlow = PTUnit( PTUnitNum ).IdleMassFlowRate;
PTUnit( PTUnitNum ).NoHeatCoolSpeedRatio = PTUnit( PTUnitNum ).IdleSpeedRatio;
if ( PTUnit( PTUnitNum ).OpMode == ContFanCycCoil ) {
PTUnit( PTUnitNum ).MaxNoCoolHeatAirVolFlow = PTUnit( PTUnitNum ).IdleVolumeAirRate;
PTUnit( PTUnitNum ).MaxNoCoolHeatAirMassFlow = PTUnit( PTUnitNum ).IdleMassFlowRate;
PTUnit( PTUnitNum ).NoHeatCoolSpeedRatio = PTUnit( PTUnitNum ).IdleSpeedRatio;
}
}
}

Expand Down Expand Up @@ -3294,7 +3295,6 @@ namespace PackagedTerminalHeatPump {
ShowContinueError( " Occurs in " + CurrentModuleObject + " = " + PTUnit( PTUnitNum ).Name );
PTUnit( PTUnitNum ).IdleVolumeAirRate = PTUnit( PTUnitNum ).FanVolFlow;
}
RhoAir = StdRhoAir;
// set the mass flow rates from the reset volume flow rates
for ( i = 1; i <= NumOfSpeedCooling; ++i ) {
PTUnit( PTUnitNum ).CoolMassFlowRate( i ) = RhoAir * PTUnit( PTUnitNum ).CoolVolumeFlowRate( i );
Expand Down Expand Up @@ -6728,8 +6728,7 @@ namespace PackagedTerminalHeatPump {
CompOnMassFlow = SpeedRatio * PTUnit( PTUnitNum ).CoolMassFlowRate( SpeedNum ) + ( 1.0 - SpeedRatio ) * PTUnit( PTUnitNum ).CoolMassFlowRate( SpeedNum - 1 );
CompOnFlowRatio = SpeedRatio * PTUnit( PTUnitNum ).MSCoolingSpeedRatio( SpeedNum ) + ( 1.0 - SpeedRatio ) * PTUnit( PTUnitNum ).MSCoolingSpeedRatio( SpeedNum - 1 );
MSHPMassFlowRateLow = PTUnit( PTUnitNum ).CoolMassFlowRate( SpeedNum - 1 );
MSHPMassFlowRateHigh = PTUnit( PTUnitNum ).CoolMassFlowRate( SpeedNum );
}
MSHPMassFlowRateHigh = PTUnit( PTUnitNum ).CoolMassFlowRate( SpeedNum ); }
}
}

Expand Down
18 changes: 18 additions & 0 deletions tst/EnergyPlus/unit/PackagedTerminalHeatPump.unit.cc
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Expand Up @@ -525,6 +525,24 @@ namespace EnergyPlus {
EXPECT_EQ( Fan( 1 ).MaxAirFlowRate, max( VariableSpeedCoils::VarSpeedCoil( 1 ).RatedAirVolFlowRate, VariableSpeedCoils::VarSpeedCoil( 2 ).RatedAirVolFlowRate ) );
EXPECT_EQ( Fan( 1 ).MaxAirFlowRate, max( PTUnit( 1 ).MaxCoolAirVolFlow, PTUnit( 1 ).MaxHeatAirVolFlow ) );

// Initialize the packaged terminal heat pump
Real64 OnOffAirFlowRatio( 1.0 ); // ratio of compressor ON airflow to average airflow over timestep
Real64 ZoneLoad( 0.0 );// cooling or heating needed by zone [watts]

InitPTUnit( 1, DataSizing::CurZoneEqNum, true, OnOffAirFlowRatio, ZoneLoad );

// check that an intermediate speed has the correct flow ratio
Real64 refAirflowRatio = 0.530468926 / 0.891980668; // speed 4 reference cooling data and full flow rate at speed 9
Real64 expectedAirFlowRate = refAirflowRatio * PTUnit( 1 ).MaxCoolAirVolFlow;
EXPECT_NEAR( expectedAirFlowRate, PTUnit( 1 ).CoolVolumeFlowRate( 4 ), 0.00001 );
EXPECT_NEAR( expectedAirFlowRate, 3.9343830134190632, 0.00001 );

refAirflowRatio = 0.530468926 / 0.891980668; // speed 4 reference heating data and full flow rate at speed 9
expectedAirFlowRate = refAirflowRatio * PTUnit( 1 ).MaxHeatAirVolFlow;
EXPECT_NEAR( expectedAirFlowRate, PTUnit( 1 ).HeatVolumeFlowRate( 4 ), 0.00001 );
EXPECT_NEAR( expectedAirFlowRate, 3.0302392264439715, 0.00001 );


}

TEST_F( EnergyPlusFixture, AirTerminalSingleDuctMixer_SimPTAC_HeatingCoilTest ) {
Expand Down