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Modify 1st-hr rating.
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Phil Ahrenkiel authored and Phil Ahrenkiel committed Jan 9, 2024
1 parent 8a1c251 commit 6f831fb
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Showing 3 changed files with 148 additions and 111 deletions.
252 changes: 143 additions & 109 deletions src/HPWH.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -5400,7 +5400,7 @@ int HPWH::HPWHinit_file(string configFile)
}
#endif

bool HPWH::findUsageFromFirstHourRating(HPWH::Usage& usage, const double setpointT_C /* = 51.7 */)
bool HPWH::prepForTest()
{
double flowRate_Lper_min = GAL_TO_L(3.);
if (tankVolume_L < GAL_TO_L(20.))
Expand All @@ -5409,118 +5409,115 @@ bool HPWH::findUsageFromFirstHourRating(HPWH::Usage& usage, const double setpoin
constexpr double inletT_C = 14.4; // p. 40433
constexpr double ambientT_C = 19.7; // p. 40435
constexpr double externalT_C = 19.7;
constexpr DRMODES drMode = DR_ALLOW;
if (!isSetpointFixed())
{
if (setSetpoint(setpointT_C, UNITS_C) == HPWH_ABORT)
{
return false;
}
}

double maxT_C = getTankTemp_C();
double prevMinT_C = getTankTemp_C();
double tolT_C = dF_TO_dC(0.); // tolerance
double tankT_C = getTankTemp_C();

double drawVolume_L = 0.;
double lastPassDrawVolume_L = 0.;
int testTime_min = 0;
int drawOnTime = 0;
int prevDrawOffTime_min = 0;
bool heatersAreOn = false;
DRMODES drMode = DR_ALLOW;
bool isDrawing = false;
bool testIsRunning = true;
int testStage = 1;
bool lastDrawSucceeded = false;
while (testIsRunning)
bool done = false;
int step = 0;
int time_min = 0;
while (!done)
{
heatersAreOn = false;
for (auto& heatSource : heatSources)
{
heatersAreOn |= heatSource.isEngaged();
}
double tankT_C = getTankTemp_C();

switch (testStage)
switch (step)
{
case 1:
case 0: // start with heat off
{
if (!heatersAreOn)
if (!isHeating)
{
isDrawing = true;
drawOnTime = testTime_min;
testStage = 2;
++step;
}
break;
}

case 2:
case 1: // draw until heat turns on
{
if (heatersAreOn)
if (isHeating)
{
isDrawing = false;
prevDrawOffTime_min = testTime_min;
maxT_C = tankT_C;
testStage = 3;
++step;
}
break;
}

case 3:
case 2: // wait for heat to turn on
{
if (isDrawing)
if (!isHeating)
{
double targetT_C = maxT_C - dF_TO_dC(15.) - tolT_C;
if (outletTemp_C < targetT_C) // outletT has dropped by 15 degF below max T
{
prevMinT_C = outletTemp_C;
maxT_C = tankT_C; // initialize for next pass
isDrawing = false;
prevDrawOffTime_min = testTime_min;
}
}
else
{
if (tankT_C > maxT_C) // has not reached max T
{
maxT_C = tankT_C + tolT_C;
if (testTime_min >= 60) // start a final draw
{
isDrawing = true;
drawOnTime = testTime_min;
testStage = 4;
}
}
else {
if (testTime_min >= 60)
{
testIsRunning = false;
}
else
{
isDrawing = true;
drawOnTime = testTime_min;
}
}
isDrawing = false;
done = true;
}
break;
}
}

case 4:
// limit draw-volume increment to tank volume
double incrementalDrawVolume_L = isDrawing ? flowRate_Lper_min * (1.) : 0.;
if (incrementalDrawVolume_L > tankVolume_L)
{
if (testTime_min > drawOnTime)
{
if (outletTemp_C > prevMinT_C - tolT_C)
{
lastDrawSucceeded = true;
}
}
if (outletTemp_C <= prevMinT_C + tolT_C)
{
testIsRunning = false;
}
incrementalDrawVolume_L = tankVolume_L;
}

if (runOneStep(inletT_C, // inlet water temperature (C)
incrementalDrawVolume_L, // draw volume (L)
ambientT_C, // ambient Temp (C)
externalT_C, // external Temp (C)
drMode, // DDR Status
0., // inlet-2 volume (L)
inletT_C, // inlet-2 Temp (C)
NULL) // no extra heat
== HPWH_ABORT)
{
return false;
}
tankT_C = getTankTemp_C();
++time_min;
}
return true;
}

bool HPWH::findUsageFromFirstHourRating(HPWH::Usage& usage, const double setpointT_C /* = 51.7 */)
{
double flowRate_Lper_min = GAL_TO_L(3.);
if (tankVolume_L < GAL_TO_L(20.))
flowRate_Lper_min = GAL_TO_L(1.5);

constexpr double inletT_C = 14.4; // p. 40433
constexpr double ambientT_C = 19.7; // p. 40435
constexpr double externalT_C = 19.7;

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

double tankT_C = getTankTemp_C();
double maxTankT_C = tankT_C;
double maxOutletT_C = 0.;

DRMODES drMode = DR_ALLOW;
double drawVolume_L = 0.;
int elapsedTime_min = 0;
int totalDrawTime_min = 0;
int totalHeatingTime_min = 0;
bool isDrawing = false;
bool done = false;
int step = 0;
int numCompletedCycles = 0;
constexpr int numCycles = 10;

prepForTest();

isDrawing = true;
maxOutletT_C = 0.;
drMode = DR_LOC;

while (!done)
{

// limit draw-volume increment to tank volume
double incrementalDrawVolume_L = isDrawing ? flowRate_Lper_min * (1.) : 0.;
Expand All @@ -5541,36 +5538,77 @@ bool HPWH::findUsageFromFirstHourRating(HPWH::Usage& usage, const double setpoin
{
return false;
}
tankT_C = getTankTemp_C();

// std::cout << preTime_min << ": " << getTankTemp_C() << ", " << (heatersAreOn? "On":
// "Off") << "\n";
if (testStage == 4)
switch (step)
{
case 0:
{
lastPassDrawVolume_L += incrementalDrawVolume_L;
++totalDrawTime_min;
maxOutletT_C = std::max(outletTemp_C, maxOutletT_C);
if (outletTemp_C < maxOutletT_C - dF_TO_dC(15.)) // outletT has dropped by 15 degF below max T
{
isDrawing = false;
drMode = DR_ALLOW;
maxTankT_C = tankT_C; // initialize for next pass
maxOutletT_C = outletTemp_C; // initialize for next pass
++step;

++numCompletedCycles;
if (numCompletedCycles >= numCycles)
{
done = true; // end with a draw
}
}
break;
}
else

case 1:
{
drawVolume_L += incrementalDrawVolume_L;
++totalHeatingTime_min;
if (isHeating) // ensure heat on before proceeding
{
++step;
}
break;
}

++testTime_min;
case 2:
{
++totalHeatingTime_min;
if ((tankT_C > maxTankT_C) &&
isHeating) // has not reached maxTankT and heat is on
{
maxTankT_C = std::max(tankT_C, maxTankT_C);
}
else // has reached maxTankT
{
isDrawing = true;
drMode = DR_LOC;
step = 0; // repeat
}
}
}
drawVolume_L += incrementalDrawVolume_L;
++elapsedTime_min;
}

if (lastDrawSucceeded)
{
drawVolume_L += lastPassDrawVolume_L;
}
double avgCyleDrawVolume_L = drawVolume_L / static_cast<double>(numCycles);
double avgCyleTime_min = elapsedTime_min / static_cast<double>(numCycles);
double avgDrawTime_min = totalDrawTime_min / static_cast<double>(numCycles);
double avgHeatingTime_min = totalHeatingTime_min / static_cast<double>(numCycles);
double hourlyDrawVolume_L = (60. / avgCyleTime_min) * avgCyleDrawVolume_L;

//
if (drawVolume_L < GAL_TO_L(18.))
if (hourlyDrawVolume_L < GAL_TO_L(18.))
{
usage = Usage::VerySmall;
}
else if (drawVolume_L < GAL_TO_L(51.))
else if (hourlyDrawVolume_L < GAL_TO_L(51.))
{
usage = Usage::Low;
}
else if (drawVolume_L < GAL_TO_L(75.))
else if (hourlyDrawVolume_L < GAL_TO_L(75.))
{
usage = Usage::Medium;
}
Expand Down Expand Up @@ -5727,6 +5765,7 @@ bool HPWH::runDailyTest(const Usage usage,
}

tankT_C = getTankTemp_C();
hasHeated |= isHeating;

drawSumOutletVolumeT_LC += incrementalDrawVolume_L * outletTemp_C;
drawSumInletVolumeT_LC += incrementalDrawVolume_L * inletT_C;
Expand All @@ -5753,13 +5792,7 @@ bool HPWH::runDailyTest(const Usage usage,
firstRecoveryUsedEnergy_kJ += usedFossilFuelEnergy_kJ + usedElectricalEnergy_kJ;
if (isDrawComplete) // check for cut-off
{
heatersAreOn = false;
for (auto& heatSource : heatSources)
{
heatersAreOn |= heatSource.isEngaged();
}
hasHeated |= heatersAreOn;
if (hasHeated && (!heatersAreOn))
if (hasHeated && (!isHeating))
{
isFirstRecoveryPeriod = false;

Expand Down Expand Up @@ -5815,13 +5848,14 @@ bool HPWH::runDailyTest(const Usage usage,
{
double tankContentMass_kg = DENSITYWATER_kgperL * tankVolume_L;
double tankHeatCapacity_kJperC = CPWATER_kJperkgC * tankContentMass_kg;
dailyTestSummary.dailyHeatingEnergyConsumption_kJ += tankHeatCapacity_kJperC *
(tankT_C - initialTankT_C) /
double finalTankT_C = tankT_C;
dailyTestSummary.dailyHeatingEnergyConsumption_kJ -= tankHeatCapacity_kJperC *
(finalTankT_C - initialTankT_C) /
dailyTestSummary.recoveryEfficiency;
}

// find the "Adjusted Daily Water Heating Energy Consumption (Qda)" (6.3.6a)
// same as above, because no change in ambient temperature
// same as above, because simulation induces no change in ambient temperature
dailyTestSummary.adjustedDailyWaterHeatingEnergyConsumption_kJ =
dailyTestSummary.dailyHeatingEnergyConsumption_kJ;

Expand Down
3 changes: 3 additions & 0 deletions src/HPWH.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -956,6 +956,9 @@ class HPWH
High
};


bool prepForTest();

/// Determine usage using the first-hour rating method
bool findUsageFromFirstHourRating(HPWH::Usage &usage,const double setpointT_C = 51.7);

Expand Down
4 changes: 2 additions & 2 deletions test/testCalcUEF.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -57,11 +57,11 @@ int main(int argc, char* argv[])
{
ASSERTTRUE(testCalcMetrics("AquaThermAire", usage, dailyTestSummary));
ASSERTTRUE(usage == HPWH::Usage::High);
ASSERTTRUE(cmpd(dailyTestSummary.UEF, 3.2797));
ASSERTTRUE(cmpd(dailyTestSummary.UEF, 2.7540));

ASSERTTRUE(testCalcMetrics("AOSmithHPTS50", usage, dailyTestSummary));
ASSERTTRUE(usage == HPWH::Usage::Medium);
ASSERTTRUE(cmpd(dailyTestSummary.UEF, 4.8246));
ASSERTTRUE(cmpd(dailyTestSummary.UEF, 2.6290));

return 0;
}
Expand Down

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