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Calc additional values.
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Phil Ahrenkiel authored and Phil Ahrenkiel committed Jan 4, 2024
1 parent d62fa56 commit 5defbd3
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Showing 3 changed files with 125 additions and 22 deletions.
124 changes: 108 additions & 16 deletions src/HPWH.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -5425,11 +5425,17 @@ HPWH::Usage HPWH::findUsageFromMaximumGPM_Rating()
return Usage::High;
}

bool HPWH::calcUEF(const Usage usage, double& UEF)
//-----------------------------------------------------------------------------
/// @brief Calculates the uniform energy factor (UEF)
/// @note see https://www.regulations.gov/document/EERE-2019-BT-TP-0032-0058
/// @param[in] usage Specification of draw pattern
/// @param[out] UEF Result of calculation
/// @return true (success), false (failure).
//-----------------------------------------------------------------------------
bool HPWH::runDailyTest(const Usage usage, DailyTestSummary &dailyTestSummary)
{

// select the draw pattern based on usage
DrawPattern* drawPattern = nullptr;

switch (usage)
{
case Usage::VerySmall:
Expand All @@ -5453,31 +5459,57 @@ bool HPWH::calcUEF(const Usage usage, double& UEF)
break;
}
}

if (drawPattern == nullptr)
{
return false;
}

const double inletT_C = 20.;
const double ambientT_C = 20.;
const double externalT_C = 20.;
const double setpointT_C = 51.7; //
const double inletT_C = 14.4; // p. 40433
const double ambientT_C = 19.7; // p. 40435
const double externalT_C = 19.7;
const DRMODES drMode = DR_ALLOW;

double totalVolumeRemoved_L = 0.;
double totalEnergyConsumed_kJ = 0.;
double dailyRemovedVolume_L = 0.;
double dailyUsedEnergy_kJ = 0.;

if (!isSetpointFixed())
{
if (setSetpoint(setpointT_C, UNITS_C) == HPWH_ABORT)
{
return false;
}
}

// first-recovery info
bool isFirstRecoveryPeriod = true;
double recoveryEfficiency = 0.;

double dailyHeatingEnergy_kJ = 0.; // total energy added to water over 24-hr test
double dailyUsedElectricalEnergy_kJ = 0.; // total electrical energy consumed over 24-hr test
double dailyUsedFossilFuelEnergy_kJ = 0.; // total "fossil-fuel" energy consumed over 24-hr test

int runTime_min = 0;
for (auto& draw : *drawPattern)
{
double drawnVolume_L = 0.;

double recoveryVolume_L = 0.;
double recoveryVolumeTemperature_LC = 0.;
double recoveryUsedElectricalEnergy_kJ = 0.;
double recoveryUsedFossilFuelEnergy_kJ = 0.;

// limit draw-volume increment to tank volume
double incrementalDrawVolume_L = draw.flowRate_Lper_min * (1.);
if (incrementalDrawVolume_L > tankVolume_L)
{
incrementalDrawVolume_L = tankVolume_L;
}

// iterate until 1) specified draw volume has been reached and 2) next draw has started
while ((drawnVolume_L < draw.volume_L) || (runTime_min < draw.startTime_min))
{
// do not exceed specified draw volume
if (drawnVolume_L + incrementalDrawVolume_L > draw.volume_L)
{
incrementalDrawVolume_L = draw.volume_L - drawnVolume_L;
Expand All @@ -5489,7 +5521,7 @@ bool HPWH::calcUEF(const Usage usage, double& UEF)
ambientT_C, // ambient Temp (C)
externalT_C, // external Temp (C)
drMode, // DDR Status
0, // inlet-2 volume (L)
0., // inlet-2 volume (L)
inletT_C, // inlet-2 Temp (C)
NULL); // no extra heat

Expand All @@ -5498,21 +5530,81 @@ bool HPWH::calcUEF(const Usage usage, double& UEF)
return false;
}

totalVolumeRemoved_L += incrementalDrawVolume_L;
// collect consumed electrical-energy info
double usedFossilFuelEnergy_kJ = 0.;
double usedElectricalEnergy_kJ = 0.;
for (int iHS = 0; iHS < getNumHeatSources(); ++iHS)
{
totalEnergyConsumed_kJ += getNthHeatSourceEnergyInput(iHS, HPWH::UNITS_KJ);
usedElectricalEnergy_kJ += getNthHeatSourceEnergyInput(iHS, HPWH::UNITS_KJ);
}

// collect recovery info
recoveryVolume_L += incrementalDrawVolume_L;
recoveryVolumeTemperature_LC += incrementalDrawVolume_L * outletTemp_C;
recoveryUsedElectricalEnergy_kJ += usedElectricalEnergy_kJ;
recoveryUsedFossilFuelEnergy_kJ += usedFossilFuelEnergy_kJ;

drawnVolume_L += incrementalDrawVolume_L;
++runTime_min;
}

// collect end-of-draw info
double recoveryUsedEnergy_kJ = recoveryUsedElectricalEnergy_kJ + recoveryUsedFossilFuelEnergy_kJ; // see 6.4.3

double recoveryOutletT_C = 0.;
if (recoveryVolume_L > 0.)
{
recoveryOutletT_C = recoveryVolumeTemperature_LC / recoveryVolume_L;
}
double recoveryMassRemoved_kg = HPWH::DENSITYWATER_kgperL * drawnVolume_L;
double recoveryHeatCapacity_kJperC = HPWH::CPWATER_kJperkgC * recoveryMassRemoved_kg;
double recoveryHeatingEnergy_kJ = recoveryHeatCapacity_kJperC * (recoveryOutletT_C - inletT_C);

if (isFirstRecoveryPeriod)
{
// find the "Recovery Efficiency" (6.4.2)
if (recoveryUsedEnergy_kJ > 0.)
{
recoveryEfficiency = recoveryHeatingEnergy_kJ / recoveryUsedEnergy_kJ;
}
isFirstRecoveryPeriod = false;
}

dailyHeatingEnergy_kJ += recoveryHeatingEnergy_kJ;

// collect 24-hr test info
dailyRemovedVolume_L += drawnVolume_L;
dailyUsedElectricalEnergy_kJ += recoveryUsedElectricalEnergy_kJ;
dailyUsedEnergy_kJ += recoveryUsedEnergy_kJ;
}

double totalMassRemoved_kg = HPWH::DENSITYWATER_kgperL * totalVolumeRemoved_L;
double totalHeatCapacity_kJperC = HPWH::CPWATER_kJperkgC * totalMassRemoved_kg;
double refEnergy_kJ = totalHeatCapacity_kJperC * (51.7 - 14.4);
// find the "Adjusted Daily Water Heating Energy Consumption" (6.3.6)
if (recoveryEfficiency > 0.)
{
dailyTestSummary.adjustedDailyWaterHeatingEnergy_kJ = dailyHeatingEnergy_kJ / recoveryEfficiency;
}

// find the "Uniform Energy Factor" (6.4.4)
double dailyMassRemoved_kg = HPWH::DENSITYWATER_kgperL * dailyRemovedVolume_L;
double dailyHeatCapacity_kJperC = HPWH::CPWATER_kJperkgC * dailyMassRemoved_kg;
double standardDailyHeatingEnergy_kJ = dailyHeatCapacity_kJperC * (setpointT_C - inletT_C);
dailyTestSummary.UEF = standardDailyHeatingEnergy_kJ / dailyUsedEnergy_kJ;

// find the "Annual Energy Consumption" (6.4.5)
double annualEnergyConsumption_kJ = 0.;
if (dailyTestSummary.UEF > 0.)
{
constexpr double day_per_year = 365.;
const double nominalDifferenceT_C = F_TO_C(67.);
annualEnergyConsumption_kJ = dailyHeatCapacity_kJperC * nominalDifferenceT_C / dailyTestSummary.UEF;
}

// find the "Annual Electrical Energy Consumption" (6.4.6)
dailyTestSummary.annualElectricalEnergyConsumption_kJ = 0.;
if (dailyUsedEnergy_kJ > 0.)
{
dailyTestSummary.annualElectricalEnergyConsumption_kJ = (dailyUsedElectricalEnergy_kJ / dailyUsedEnergy_kJ) * annualEnergyConsumption_kJ;
}

UEF = refEnergy_kJ / totalEnergyConsumed_kJ;
return true;
}
13 changes: 11 additions & 2 deletions src/HPWH.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -959,8 +959,17 @@ class HPWH
/// Determine usage using the maximum GPM rating method
Usage findUsageFromMaximumGPM_Rating();

/// Calculate UEF
bool calcUEF(const Usage usage, double& UEF);
struct DailyTestSummary
{
double UEF;
double recoveryEfficiency;
double adjustedDailyWaterHeatingEnergy_kJ;
double annualElectricalEnergyConsumption_kJ;
double annualEnergyConsumption_kJ;
};

/// run 24-hr draw pattern
bool runDailyTest(const Usage usage, DailyTestSummary &dailyTestSummary);

struct Draw
{
Expand Down
10 changes: 6 additions & 4 deletions test/testCalcUEF.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,9 @@ static bool testCalcUEF(const std::string& sModelName, double& UEF)
return false;
}

return hpwh.calcUEF(hpwh.findUsageFromMaximumGPM_Rating(), UEF);
HPWH::DailyTestSummary dailyTestSummary;
return hpwh.runDailyTest(hpwh.findUsageFromMaximumGPM_Rating(), dailyTestSummary);
UEF = dailyTestSummary.UEF;
}

int main(int argc, char* argv[])
Expand Down Expand Up @@ -101,10 +103,10 @@ int main(int argc, char* argv[])
std::cout << "Spec type: " << sPresetOrFile << "\n";
std::cout << "Model name: " << sModelName << "\n";

double UEF = 0.;
if(hpwh.calcUEF(hpwh.findUsageFromMaximumGPM_Rating(), UEF))
HPWH::DailyTestSummary dailyTestSummary;
if(hpwh.runDailyTest(hpwh.findUsageFromMaximumGPM_Rating(), dailyTestSummary))
{
std::cout << "UEF: " << UEF << "\n";
std::cout << "UEF: " << dailyTestSummary.UEF << "\n";
}
else
{
Expand Down

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