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Merge pull request #183 from bigladder/heat-exchange-models
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Heat exchange models
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@nealkruis
nealkruis authored Dec 19, 2023
2 parents e4d69fa + ad4f931 commit 58dd30b
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Showing 317 changed files with 5,017 additions and 369 deletions.
190 changes: 136 additions & 54 deletions src/HPWH.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -315,6 +315,8 @@ void HPWH::setAllDefaults() {
usesSoCLogic = false;
setMinutesPerStep(1.0);
hpwhVerbosity = VRB_minuteOut;
hasHeatExchanger = false;
heatExchangerEffectiveness = 0.9;
}

HPWH::HPWH(const HPWH &hpwh) {
Expand Down Expand Up @@ -938,7 +940,7 @@ int HPWH::WriteCSVHeading(FILE* outFILE,const char* preamble,int nTCouples,int o
fprintf(outFILE,",tcouple%d (%s)",iTC + 1,doIP ? "F" : "C");
}

fprintf(outFILE,", toutlet (%s)",doIP ? "F" : "C");
fprintf(outFILE,",toutlet (%s)",doIP ? "F" : "C");

fprintf(outFILE,"\n");

Expand Down Expand Up @@ -1738,14 +1740,26 @@ std::vector<HPWH::NodeWeight> HPWH::getNodeWeightRange(double bottomFraction, do
return nodeWeights;
}

std::shared_ptr<HPWH::TempBasedHeatingLogic> HPWH::wholeTank(double decisionPoint,const UNITS units /* = UNITS_C */, const bool absolute /* = false */) {
std::vector<NodeWeight> nodeWeights = getNodeWeightRange(0., 1.);
double decisionPoint_C = convertTempToC(decisionPoint,units,absolute);
return std::make_shared<HPWH::TempBasedHeatingLogic>("whole tank",nodeWeights,decisionPoint_C,this,absolute);
}

std::shared_ptr<HPWH::TempBasedHeatingLogic> HPWH::topThird(double decisionPoint) {
std::vector<NodeWeight> nodeWeights = getNodeWeightRange(2./3., 1.);
return std::make_shared<HPWH::TempBasedHeatingLogic>("top third",nodeWeights,decisionPoint,this);
}

std::shared_ptr<HPWH::TempBasedHeatingLogic> HPWH::topThird_absolute(double decisionPoint) {
std::vector<NodeWeight> nodeWeights = getNodeWeightRange(2./3., 1.);
return std::make_shared<HPWH::TempBasedHeatingLogic>("top third absolute",nodeWeights,decisionPoint,this);
return std::make_shared<HPWH::TempBasedHeatingLogic>("top third absolute",nodeWeights,decisionPoint,this,true);
}

std::shared_ptr<HPWH::TempBasedHeatingLogic> HPWH::secondThird(double decisionPoint,const UNITS units /* = UNITS_C */, const bool absolute /* = false */) {
std::vector<NodeWeight> nodeWeights = getNodeWeightRange(1./3., 2./3.);
double decisionPoint_C = convertTempToC(decisionPoint,units,absolute);
return std::make_shared<HPWH::TempBasedHeatingLogic>("second third",nodeWeights,decisionPoint_C,this,absolute);
}

std::shared_ptr<HPWH::TempBasedHeatingLogic> HPWH::bottomThird(double decisionPoint) {
Expand Down Expand Up @@ -2581,77 +2595,93 @@ void HPWH::updateTankTemps(double drawVolume_L,double inletT_C,double tankAmbien
lowInletT = inletT_C;
lowInletV = drawVolume_L - inletVol2_L;
}
//calculate how many nodes to draw (drawVolume_N)
double drawVolume_N = drawVolume_L / nodeVolume_L;
if(drawVolume_L > tankVolume_L) {
//if (hpwhVerbosity >= VRB_reluctant) {
// //msg("WARNING: Drawing more than the tank volume in one step is undefined behavior. Terminating simulation. \n");
// msg("WARNING: Drawing more than the tank volume in one step is undefined behavior. Continuing simulation at your own risk. \n");
//}
//simHasFailed = true;
//return;
for(int i = 0; i < getNumNodes(); i++){
outletTemp_C += tankTemps_C[i];
tankTemps_C[i] = (inletT_C * (drawVolume_L - inletVol2_L) + inletT2_C * inletVol2_L) / drawVolume_L;
}
outletTemp_C = (outletTemp_C / getNumNodes() * tankVolume_L + tankTemps_C[0] * (drawVolume_L - tankVolume_L))
/ drawVolume_L * drawVolume_N;

drawVolume_N = 0.;
if (hasHeatExchanger) {// heat-exchange models

const double densityTank_kgperL = DENSITYWATER_kgperL;
const double CpTank_kJperkgC = CPWATER_kJperkgC;

double C_Node_kJperC = CpTank_kJperkgC * densityTank_kgperL * nodeVolume_L;
double C_draw_kJperC = CPWATER_kJperkgC * DENSITYWATER_kgperL * drawVolume_L;

outletTemp_C = inletT_C;
for (auto &nodeTemp: tankTemps_C) {
double maxHeatExchange_kJ = C_draw_kJperC * (nodeTemp - outletTemp_C);
double heatExchange_kJ = nodeHeatExchangerEffectiveness * maxHeatExchange_kJ;

nodeTemp -= heatExchange_kJ / C_Node_kJperC;
outletTemp_C += heatExchange_kJ / C_draw_kJperC;
}
}
else {
//calculate how many nodes to draw (drawVolume_N)
double drawVolume_N = drawVolume_L / nodeVolume_L;
if(drawVolume_L > tankVolume_L) {
//if (hpwhVerbosity >= VRB_reluctant) {
// //msg("WARNING: Drawing more than the tank volume in one step is undefined behavior. Terminating simulation. \n");
// msg("WARNING: Drawing more than the tank volume in one step is undefined behavior. Continuing simulation at your own risk. \n");
//}
//simHasFailed = true;
//return;
for(int i = 0; i < getNumNodes(); i++){
outletTemp_C += tankTemps_C[i];
tankTemps_C[i] = (inletT_C * (drawVolume_L - inletVol2_L) + inletT2_C * inletVol2_L) / drawVolume_L;
}
outletTemp_C = (outletTemp_C / getNumNodes() * tankVolume_L + tankTemps_C[0] * (drawVolume_L - tankVolume_L))
/ drawVolume_L * drawVolume_N;

/////////////////////////////////////////////////////////////////////////////////////////////////
drawVolume_N = 0.;
}

while(drawVolume_N > 0) {

while(drawVolume_N > 0) {
// Draw one node at a time
double drawFraction = drawVolume_N > 1. ? 1. : drawVolume_N;
double nodeInletTV = 0.;

// Draw one node at a time
double drawFraction = drawVolume_N > 1. ? 1. : drawVolume_N;
double nodeInletTV = 0.;
//add temperature for outletT average
outletTemp_C += drawFraction * tankTemps_C[getNumNodes() - 1];

//add temperature for outletT average
outletTemp_C += drawFraction * tankTemps_C[getNumNodes() - 1];
double cumInletFraction = 0.;
for(int i = getNumNodes() - 1; i >= lowInletH; i--) {

double cumInletFraction = 0.;
for(int i = getNumNodes() - 1; i >= lowInletH; i--) {

// Reset inlet inputs at this node.
double nodeInletFraction = 0.;
nodeInletTV = 0.;

// Sum of all inlets Vi*Ti at this node
if(i == highInletH) {
nodeInletTV += highInletV * drawFraction / drawVolume_L * highInletT;
nodeInletFraction += highInletV * drawFraction / drawVolume_L;
nodeInletTV += highInletV * drawFraction / drawVolume_L * highInletT;
nodeInletFraction += highInletV * drawFraction / drawVolume_L;
}
if(i == lowInletH) {
nodeInletTV += lowInletV * drawFraction / drawVolume_L * lowInletT;
nodeInletFraction += lowInletV * drawFraction / drawVolume_L;
nodeInletTV += lowInletV * drawFraction / drawVolume_L * lowInletT;
nodeInletFraction += lowInletV * drawFraction / drawVolume_L;

break; // if this is the bottom inlet break out of the four loop and use the boundary condition equation.
}

// Look at the volume and temperature fluxes into this node
tankTemps_C[i] = (1. - (drawFraction - cumInletFraction)) * tankTemps_C[i] +
nodeInletTV +
(drawFraction - (cumInletFraction + nodeInletFraction)) * tankTemps_C[i - 1];

cumInletFraction += nodeInletFraction;
// Look at the volume and temperature fluxes into this node
tankTemps_C[i] = (1. - (drawFraction - cumInletFraction)) * tankTemps_C[i] +
nodeInletTV +
(drawFraction - (cumInletFraction + nodeInletFraction)) * tankTemps_C[i - 1];

}

// Boundary condition equation because it shouldn't take anything from tankTemps_C[i - 1] but it also might not exist.
tankTemps_C[lowInletH] = (1. - (drawFraction - cumInletFraction)) * tankTemps_C[lowInletH] + nodeInletTV;
cumInletFraction += nodeInletFraction;

drawVolume_N -= drawFraction;
}

mixTankInversions();
}
// Boundary condition equation because it shouldn't take anything from tankTemps_C[i - 1] but it also might not exist.
tankTemps_C[lowInletH] = (1. - (drawFraction - cumInletFraction)) * tankTemps_C[lowInletH] + nodeInletTV;

drawVolume_N -= drawFraction;

//fill in average outlet T - it is a weighted averaged, with weights == nodes drawn
this->outletTemp_C /= (drawVolume_L / nodeVolume_L);
mixTankInversions();
}

/////////////////////////////////////////////////////////////////////////////////////////////////
//fill in average outlet T - it is a weighted averaged, with weights == nodes drawn
outletTemp_C /= (drawVolume_L / nodeVolume_L);
}

//Account for mixing at the bottom of the tank
if(tankMixesOnDraw && drawVolume_L > 0.) {
Expand Down Expand Up @@ -3024,6 +3054,9 @@ void HPWH::calcSizeConstants() {

// fracAreaSide is the faction of the area of the cylinder that's not the top or bottom.
fracAreaSide = tankHeight_m / (tankHeight_m + tankRad_m);

/// Single-node heat-exchange effectiveness
nodeHeatExchangerEffectiveness = 1. - pow(1. - heatExchangerEffectiveness, 1./ static_cast<double>(getNumNodes()));
}

void HPWH::calcDerivedValues() {
Expand Down Expand Up @@ -3141,7 +3174,6 @@ void HPWH::mapResRelativePosToHeatSources() {
});
}


// Used to check a few inputs after the initialization of a tank model from a preset or a file.
int HPWH::checkInputs() {
int returnVal = 0;
Expand Down Expand Up @@ -3194,7 +3226,8 @@ int HPWH::checkInputs() {

//check is condensity sums to 1
condensitySum = 0;
for(int j = 0; j < heatSources[i].getCondensitySize(); ++j) condensitySum += heatSources[i].condensity[j];

for(int j = 0; j < heatSources[i].getCondensitySize(); j++) condensitySum += heatSources[i].condensity[j];
if(fabs(condensitySum - 1.0) > 1e-6) {
if(hpwhVerbosity >= VRB_reluctant) {
msg("The condensity for heatsource %d does not sum to 1. \n",i);
Expand Down Expand Up @@ -3328,6 +3361,14 @@ int HPWH::checkInputs() {
returnVal = HPWH_ABORT;
}

// Check single-node heat-exchange effectiveness validity
if( heatExchangerEffectiveness > 1.) {
if(hpwhVerbosity >= VRB_reluctant) {
msg("Heat-exchanger effectiveness cannot exceed 1.\n");
}
returnVal = HPWH_ABORT;
}

//if there's no failures, return 0
return returnVal;
}
Expand Down Expand Up @@ -3515,7 +3556,21 @@ int HPWH::HPWHinit_file(string configFile) {
}
initalTankT_C = tempDouble;
hasInitialTankTemp = true;

} else if(token == "hasHeatExchanger") {
// false of this model uses heat exchange
line_ss >> tempString;
if(tempString == "true") hasHeatExchanger = true;
else if(tempString == "false") hasHeatExchanger = false;
else {
if(hpwhVerbosity >= VRB_reluctant) {
msg("Improper value for %s\n",token.c_str());
}
return HPWH_ABORT;
}
} else if(token == "heatExchangerEffectiveness") {
// applies to heat-exchange models only
line_ss >> tempDouble;
heatExchangerEffectiveness = tempDouble;
} else if(token == "verbosity") {
line_ss >> token;
if(token == "silent") {
Expand Down Expand Up @@ -3668,16 +3723,43 @@ int HPWH::HPWHinit_file(string configFile) {
heatSources[heatsource].standbyLogic = std::make_shared<HPWH::TempBasedHeatingLogic>("standby logic",nodeWeights,tempDouble,this,absolute,compare);
}
} else if(token == "onlogic") {
line_ss >> tempDouble >> units;
if(units == "F") tempDouble = dF_TO_dC(tempDouble);
else if(units == "C"); //do nothing, lol
std::string nextToken;
line_ss >> nextToken;
bool absolute = (nextToken == "absolute");
if(absolute) {
std::string compareStr;
line_ss >> compareStr >> tempDouble >> units;
std::function<bool(double,double)> compare;
if(compareStr == "<") compare = std::less<double>();
else if(compareStr == ">") compare = std::greater<double>();
else {
if(hpwhVerbosity >= VRB_reluctant) {
msg("Improper comparison, \"%s\", for heat source %d %s. Should be \"<\" or \">\".\n",compareStr.c_str(),heatsource,token.c_str());
}
return HPWH_ABORT;
}
line_ss >> tempDouble;
}
else {
tempDouble = std::stod(nextToken);
}
line_ss >> units;
if(units == "F") {
if(absolute) {
tempDouble = F_TO_C(tempDouble);
} else {
tempDouble = dF_TO_dC(tempDouble);
}
} else if(units == "C"); //do nothing, lol
else {
if(hpwhVerbosity >= VRB_reluctant) {
msg("Incorrect units specification for %s from heatsource %d. \n",token.c_str(),heatsource);
}
return HPWH_ABORT;
}
if(tempString == "topThird") {
if(tempString == "wholeTank") {
heatSources[heatsource].addTurnOnLogic(HPWH::wholeTank(tempDouble,UNITS_C,absolute));
} else if(tempString == "topThird") {
heatSources[heatsource].addTurnOnLogic(HPWH::topThird(tempDouble));
} else if(tempString == "bottomThird") {
heatSources[heatsource].addTurnOnLogic(HPWH::bottomThird(tempDouble));
Expand Down
27 changes: 20 additions & 7 deletions src/HPWH.hh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -216,7 +216,9 @@ public:
MODELS_RHEEM_HPHD60HNU_201_MP = 350,
MODELS_RHEEM_HPHD60VNU_201_MP = 351,
MODELS_RHEEM_HPHD135HNU_483_MP = 352, // really bad fit to data due to inconsistency in data
MODELS_RHEEM_HPHD135VNU_483_MP = 353 // really bad fit to data due to inconsistency in data
MODELS_RHEEM_HPHD135VNU_483_MP = 353, // really bad fit to data due to inconsistency in data

MODELS_AquaThermAire = 400 // heat exchanger model
};

///specifies the modes for writing output
Expand Down Expand Up @@ -372,8 +374,10 @@ public:
std::shared_ptr<HPWH::SoCBasedHeatingLogic> turnOnSoC(std::string desc,double targetSoC,double hystFract,double tempMinUseful_C,
bool constMains,double mains_C);

std::shared_ptr<TempBasedHeatingLogic> wholeTank(double decisionPoint,const UNITS units = UNITS_C, const bool absolute = false);
std::shared_ptr<TempBasedHeatingLogic> topThird(double decisionPoint);
std::shared_ptr<TempBasedHeatingLogic> topThird_absolute(double decisionPoint);
std::shared_ptr<TempBasedHeatingLogic> secondThird(double decisionPoint,const UNITS units = UNITS_C, const bool absolute = false);
std::shared_ptr<TempBasedHeatingLogic> bottomThird(double decisionPoint);
std::shared_ptr<TempBasedHeatingLogic> bottomHalf(double decisionPoint) ;
std::shared_ptr<TempBasedHeatingLogic> bottomTwelfth(double decisionPoint);
Expand Down Expand Up @@ -708,11 +712,6 @@ public:
energy put into the water is positive - should always be positive
returns HPWH_ABORT for N out of bounds or incorrect units */

double getNthHeatSourceExtraEnergyInput(int N,UNITS units = UNITS_KWH) const;
/**< returns the "extra" energy input to the Nth heat source, with the specified units
energy used by the heat source is positive - should always be positive
returns HPWH_ABORT for N out of bounds or incorrect units */

double getNthHeatSourceRunTime(int N) const;
/**< returns the run time for the Nth heat source, in minutes
note: they may sum to more than 1 time step for concurrently running heat sources
Expand Down Expand Up @@ -939,7 +938,7 @@ private:
/**< the mass of water (kg) in a single node */
double nodeMass_kg;

/**< the heat capacity of the water (kJ/°C) in a single node */
/**< the heat capacity of the water (kJ/�C) in a single node */
double nodeCp_kJperC;

/**< the height in meters of the one node */
Expand Down Expand Up @@ -1026,6 +1025,15 @@ private:
/// Generates a vector of logical nodes
std::vector<HPWH::NodeWeight> getNodeWeightRange(double bottomFraction,double topFraction);

/// False: water is drawn from the tank itself; True: tank provides heat exchange only
bool hasHeatExchanger;

/// Coefficient (0-1) of effectiveness for heat exchange between tank and water line (used by heat-exchange models only).
double heatExchangerEffectiveness;

/// Coefficient (0-1) of effectiveness for heat exchange between a single tank node and water line (derived from heatExchangerEffectiveness).
double nodeHeatExchangerEffectiveness;

}; //end of HPWH class

class HPWH::HeatSource {
Expand Down Expand Up @@ -1350,6 +1358,11 @@ inline HPWH::DRMODES operator|(HPWH::DRMODES a,HPWH::DRMODES b)

template< typename T> inline bool aboutEqual(T a,T b) { return fabs(a - b) < HPWH::TOL_MINVALUE; }

/// Generate an absolute or relative temperature in degC.
inline double convertTempToC(const double T_F_or_C,const HPWH::UNITS units,const bool absolute){
return (units == HPWH::UNITS_C) ? T_F_or_C : (absolute ? F_TO_C(T_F_or_C) : dF_TO_dC(T_F_or_C));
}

// resampling utility functions
double getResampledValue(const std::vector<double> &values,double beginFraction,double endFraction);
bool resample(std::vector<double> &values,const std::vector<double> &sampleValues);
Expand Down
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