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Implementation of On-Off Control Capabilities for the Variable Flow and Electric Low Temperature Radiant Systems #8113

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merged 6 commits into from
Jul 1, 2020
Merged

Implementation of On-Off Control Capabilities for the Variable Flow and Electric Low Temperature Radiant Systems #8113

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b233cce
Addition of On/Off Control
RKStrand Jun 26, 2020
a23f07f
Merge branch 'develop' into 8044-LowTempRadSysOnOffControl
RKStrand Jun 26, 2020
a6129ad
On-Off Control Sub Unit Test
RKStrand Jun 26, 2020
1780fc5
Merge branch 'develop' into 8044-LowTempRadSysOnOffControl
RKStrand Jun 30, 2020
1175dd7
Removal of checks on throttling range
RKStrand Jun 30, 2020
e14abb6
Rebug the code
RKStrand Jul 1, 2020
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4 changes: 2 additions & 2 deletions idd/Energy+.idd.in
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Original file line number Diff line number Diff line change
Expand Up @@ -44069,7 +44069,7 @@ ZoneHVAC:LowTemperatureRadiant:VariableFlow,
\type node
N7 , \field Heating Control Throttling Range
\units deltaC
\minimum 0.5
\minimum 0
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Makes sense, users can now have zero range to give on/off control.

\default 0.5
A9 , \field Heating Control Temperature Schedule Name
\type object-list
Expand Down Expand Up @@ -44117,7 +44117,7 @@ ZoneHVAC:LowTemperatureRadiant:VariableFlow,
\type node
N12, \field Cooling Control Throttling Range
\units deltaC
\minimum 0.5
\minimum 0
\default 0.5
A13, \field Cooling Control Temperature Schedule Name
\type object-list
Expand Down
36 changes: 16 additions & 20 deletions src/EnergyPlus/LowTempRadiantSystem.cc
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Expand Up @@ -368,7 +368,6 @@ namespace LowTempRadiantSystem {
using namespace DataSurfaceLists;

// SUBROUTINE PARAMETER DEFINITIONS:
Real64 const MinThrottlingRange(0.5); // Smallest throttling range allowed in degrees Celsius
static std::string const RoutineName("GetLowTempRadiantSystem: "); // include trailing blank space
static std::string const Off("Off");
static std::string const SimpleOff("SimpleOff");
Expand Down Expand Up @@ -664,11 +663,6 @@ namespace LowTempRadiantSystem {
}

thisRadSys.HotThrottlRange = Numbers(7);
if (thisRadSys.HotThrottlRange < MinThrottlingRange) {
ShowWarningError("ZoneHVAC:LowTemperatureRadiant:VariableFlow: Heating throttling range too small, reset to 0.5");
ShowContinueError("Occurs in Radiant System=" + thisRadSys.Name);
thisRadSys.HotThrottlRange = MinThrottlingRange;
}
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Yay gone!


thisRadSys.HotSetptSched = Alphas(9);
thisRadSys.HotSetptSchedPtr = GetScheduleIndex(Alphas(9));
Expand Down Expand Up @@ -760,11 +754,6 @@ namespace LowTempRadiantSystem {
}

thisRadSys.ColdThrottlRange = Numbers(12);
if (thisRadSys.ColdThrottlRange < MinThrottlingRange) {
ShowWarningError("ZoneHVAC:LowTemperatureRadiant:VariableFlow: Cooling throttling range too small, reset to 0.5");
ShowContinueError("Occurs in Radiant System=" + thisRadSys.Name);
thisRadSys.ColdThrottlRange = MinThrottlingRange;
}

thisRadSys.ColdSetptSched = Alphas(13);
thisRadSys.ColdSetptSchedPtr = GetScheduleIndex(Alphas(13));
Expand Down Expand Up @@ -1225,11 +1214,6 @@ namespace LowTempRadiantSystem {
thisElecSys.ControlType = thisElecSys.processRadiantSystemControlInput(Alphas(6),cAlphaFields(6));

thisElecSys.ThrottlRange = Numbers(4);
if (thisElecSys.ThrottlRange < MinThrottlingRange) {
ShowWarningError(cNumericFields(4) + " out of range, reset to 0.5");
ShowContinueError("Occurs in " + CurrentModuleObject + " = " + Alphas(1));
thisElecSys.ThrottlRange = MinThrottlingRange;
}

thisElecSys.SetptSched = Alphas(7);
thisElecSys.SetptSchedPtr = GetScheduleIndex(Alphas(7));
Expand Down Expand Up @@ -3107,12 +3091,12 @@ namespace LowTempRadiantSystem {
OperatingMode = HeatingMode;
ControlNode = this->HotWaterInNode;
MaxWaterFlow = this->WaterFlowMaxHeat;
MassFlowFrac = (OffTempHeat - ControlTemp) / this->HotThrottlRange;
MassFlowFrac = this->calculateOperationalFraction(OffTempHeat, ControlTemp, this->HotThrottlRange);
} else if (ControlTemp > OffTempCool && this->CoolingSystem) { // Cooling mode
OperatingMode = CoolingMode;
ControlNode = this->ColdWaterInNode;
MaxWaterFlow = this->WaterFlowMaxCool;
MassFlowFrac = (ControlTemp - OffTempCool) / this->ColdThrottlRange;
MassFlowFrac = this->calculateOperationalFraction(OffTempCool, ControlTemp, this->ColdThrottlRange);
} else { // ControlTemp is between OffTempHeat and OffTempCool--unit should not run
MassFlowFrac = 0.0;
}
Expand Down Expand Up @@ -4771,8 +4755,7 @@ namespace LowTempRadiantSystem {

OperatingMode = HeatingMode;

HeatFrac = (OffTemp - ControlTemp) / this->ThrottlRange;
if (HeatFrac < 0.0) HeatFrac = 0.0;
HeatFrac = this->calculateOperationalFraction(OffTemp, ControlTemp, this->ThrottlRange);
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Code reuse! w00t!

if (HeatFrac > 1.0) HeatFrac = 1.0;

// Set the heat source for the low temperature electric radiant system
Expand Down Expand Up @@ -5087,6 +5070,19 @@ namespace LowTempRadiantSystem {
}
}

Real64 RadiantSystemBaseData::calculateOperationalFraction(Real64 const offTemperature, Real64 const controlTemperature, Real64 const throttlingRange)
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Hooray for a base class method!

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Let's just say I had a great teacher! I was definitely following examples from the previous radiant work. Glad to be doing things in a way that heads E+ in the right direction.

{
Real64 temperatureDifference = std::abs(offTemperature - controlTemperature);
if (temperatureDifference <= 0.0) {
return 0.0; // No temperature difference--turn things off (set to zero); technically shouldn't happen
} else if (throttlingRange < 0.001) {
return 1.0; // Throttling range is essentially zero and there is a temperature difference--turn it full on
} else {
return temperatureDifference/throttlingRange; // Temperature difference is non-zero and less than the throttling range--calculate the operation fraction
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There should be a space before and after the division operator.

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Will fix this when we resolve the minimum throttling range issue.

}
}


Real64 HydronicSystemBaseData::calculateHXEffectivenessTerm(Real64 const Temperature, // Temperature of water entering the radiant system, in C
Real64 const WaterMassFlow, // Mass flow rate of water in the radiant system, in kg/s
Real64 const FlowFraction, // Mass flow rate fraction for this surface in the radiant system
Expand Down
6 changes: 4 additions & 2 deletions src/EnergyPlus/LowTempRadiantSystem.hh
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Expand Up @@ -159,9 +159,11 @@ namespace LowTempRadiantSystem {
);

Real64 setRadiantSystemControlTemperature();


Real64 calculateOperationalFraction(Real64 const offTemperature, Real64 const controlTemperature, Real64 const throttlingRange);

virtual void calculateLowTemperatureRadiantSystem(ZoneTempPredictorCorrectorData &dataZoneTempPredictorCorrector, Real64 &LoadMet) = 0;

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Your editor left some trailing white space on this line, no worries for now, but I'd check to see if you can tell it to remove them upon saving the file.

void updateLowTemperatureRadiantSystemSurfaces();

virtual void updateLowTemperatureRadiantSystem() = 0;
Expand Down
2 changes: 1 addition & 1 deletion testfiles/RadLoTempElecCtrlOpt2.idf
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Expand Up @@ -2216,7 +2216,7 @@
, !- Heating Design Capacity Per Floor Area {W/m2}
1.9637972000759794, !- Fraction of Autosized Heating Design Capacity
SurfaceInteriorTemperature, !- Temperature Control Type
2.0, !- Heating Throttling Range {deltaC}
0.0, !- Heating Throttling Range {deltaC}
Radiant Heating Setpoints 3; !- Heating Setpoint Temperature Schedule Name

AirLoopHVAC:ZoneSplitter,
Expand Down
8 changes: 4 additions & 4 deletions testfiles/RadLoTempHydrHeatCool.idf
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Expand Up @@ -2097,7 +2097,7 @@
0.00008, !- Maximum Hot Water Flow {m3/s}
East Zone Radiant Water Inlet Node, !- Heating Water Inlet Node Name
East Zone Radiant Water Outlet Node, !- Heating Water Outlet Node Name
2.0, !- Heating Control Throttling Range {deltaC}
0.4, !- Heating Control Throttling Range {deltaC}
Radiant Heating Setpoints, !- Heating Control Temperature Schedule Name
CoolingDesignCapacity, !- Cooling Design Capacity Method
Autosize, !- Cooling Design Capacity {W}
Expand All @@ -2106,7 +2106,7 @@
0.0012, !- Maximum Cold Water Flow {m3/s}
Zone 2 Cooling Water Inlet Node, !- Cooling Water Inlet Node Name
Zone 2 Cooling Water Outlet Node, !- Cooling Water Outlet Node Name
2.0, !- Cooling Control Throttling Range {deltaC}
0.4, !- Cooling Control Throttling Range {deltaC}
Radiant Cooling Setpoints, !- Cooling Control Temperature Schedule Name
VariableOff, !- Condensation Control Type
0.0, !- Condensation Control Dewpoint Offset {C}
Expand All @@ -2128,7 +2128,7 @@
0.00010, !- Maximum Hot Water Flow {m3/s}
North Zone Radiant Water Inlet Node, !- Heating Water Inlet Node Name
North Zone Radiant Water Outlet Node, !- Heating Water Outlet Node Name
2.0, !- Heating Control Throttling Range {deltaC}
0.0, !- Heating Control Throttling Range {deltaC}
Radiant Heating Setpoints, !- Heating Control Temperature Schedule Name
CoolingDesignCapacity, !- Cooling Design Capacity Method
Autosize, !- Cooling Design Capacity {W}
Expand All @@ -2137,7 +2137,7 @@
0.0015, !- Maximum Cold Water Flow {m3/s}
Zone 3 Cooling Water Inlet Node, !- Cooling Water Inlet Node Name
Zone 3 Cooling Water Outlet Node, !- Cooling Water Outlet Node Name
2.0, !- Cooling Control Throttling Range {deltaC}
0.0, !- Cooling Control Throttling Range {deltaC}
Radiant Cooling Setpoints, !- Cooling Control Temperature Schedule Name
Off, !- Condensation Control Type
0.0, !- Condensation Control Dewpoint Offset {C}
Expand Down
69 changes: 69 additions & 0 deletions tst/EnergyPlus/unit/LowTempRadiantSystem.unit.cc
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Expand Up @@ -2132,3 +2132,72 @@ TEST_F(LowTempRadiantSystemTest, setRadiantSystemControlTemperatureTest)
EXPECT_NEAR(expectedResult, actualResult, acceptibleError);

}

TEST_F(LowTempRadiantSystemTest, calculateOperationalFractionTest)
{
Real64 offTemperature;
Real64 controlTemperature;
Real64 throttlingRange;
Real64 functionResult;
Real64 expectedResult;

HydrRadSys.allocate(1);
auto &thisRadSys (HydrRadSys(1));

// Test 1: Temperature Difference is 0-->answer should be 0.0
offTemperature = 15.0;
controlTemperature = 15.0;
throttlingRange = 1.0;
expectedResult = 0.0;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 2a: Temperature Difference is not zero and positive, throttling range is zero-->answer should be 1.0
offTemperature = 16.0;
controlTemperature = 15.0;
throttlingRange = 0.0;
expectedResult = 1.0;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 2b: Temperature Difference is not zero and negtive, throttling range is zero-->answer should be 1.0
offTemperature = 14.0;
controlTemperature = 15.0;
throttlingRange = 0.0;
expectedResult = 1.0;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 3a: Temperature Difference is not zero and positive, throttling range is non-zero but less than temperature difference
offTemperature = 16.0;
controlTemperature = 15.0;
throttlingRange = 0.5;
expectedResult = 2.0;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 3b: Temperature Difference is not zero and negative, throttling range is non-zero but less than temperature difference
offTemperature = 16.0;
controlTemperature = 15.0;
throttlingRange = 0.5;
expectedResult = 2.0;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 4a: Temperature Difference is not zero and positive, throttling range is non-zero but greater than temperature difference
offTemperature = 16.0;
controlTemperature = 15.0;
throttlingRange = 2.0;
expectedResult = 0.5;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

// Test 4b: Temperature Difference is not zero and negative, throttling range is non-zero but greater than temperature difference
offTemperature = 14.0;
controlTemperature = 15.0;
throttlingRange = 2.0;
expectedResult = 0.5;
functionResult = thisRadSys.calculateOperationalFraction(offTemperature, controlTemperature, throttlingRange);
EXPECT_NEAR(expectedResult, functionResult, 0.001);

}