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HtfCycle.cpp
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HtfCycle.cpp
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/*-------------------------------------------------------------------------------*/
/* SOLAR - The solar thermal power plant simulator */
/* https://github.com/bbopt/solar */
/* */
/* Miguel Diago, Sebastien Le Digabel, Mathieu Lemyre-Garneau, Bastien Talgorn */
/* */
/* Polytechnique Montreal / GERAD */
/* sebastien.le-digabel@polymtl.ca */
/* */
/* This program is free software: you can redistribute it and/or modify it */
/* under the terms of the GNU Lesser General Public License as published by */
/* the Free Software Foundation, either version 3 of the License, or (at your */
/* option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, but WITHOUT */
/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License */
/* for more details. */
/* */
/* You should have received a copy of the GNU Lesser General Public License */
/* along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* */
/*-------------------------------------------------------------------------------*/
#include "HtfCycle.hpp"
/*----------------------------------------------------------------*/
/* constructor #1 */
/*----------------------------------------------------------------*/
HtfCycle::HtfCycle ( double receiverTemp ,
double storageHeight ,
double storageDiameter ,
double insulationThickness ,
double exchangerExitTemp ,
Powerblock * powerblock ,
double apertureHeight ,
double apertureWidth ,
double receiverTubesDin ,
double receiverTubesThickness ,
int receiverNbTubes ,
int timeInterval ) :
// Mechanical components:
_centralReceiver ( &_centralReceiverInlet ,
&_centralReceiverOutlet,
apertureHeight ,
apertureWidth ,
insulationThickness ,
receiverTubesDin ,
receiverTubesThickness ,
receiverNbTubes ) ,
_hotStorage ( &_centralReceiverOutlet ,
&_steamGeneratorInlet ,
storageHeight ,
storageDiameter ,
insulationThickness ) ,
_coldStorage ( &_steamGeneratorOutlet ,
&_centralReceiverInlet ,
1.2*storageHeight ,
storageDiameter ,
insulationThickness ) ,
_steamGenerator ( &_steamGeneratorInlet, &_steamGeneratorOutlet, powerblock ) ,
// MoltenSalt conditions:
_centralReceiverInlet ( exchangerExitTemp, P_ATM, 0.0 ) ,
_centralReceiverOutlet ( receiverTemp , P_ATM, 0.0 ) ,
_steamGeneratorInlet ( receiverTemp , P_ATM, 0.0 ) ,
_steamGeneratorOutlet ( exchangerExitTemp, P_ATM, 0.0 ) ,
_timeInterval ( timeInterval ) {
_steamGenOutletMsRate.reserve ( 1440 * _timeInterval ); // 1440=24x60
_steamGenOutletTemp.reserve ( 1440 * _timeInterval );
_storageHeat.reserve ( 1440 * _timeInterval );
_minColdStorageTemp = exchangerExitTemp;
_minHotStorageTemp = receiverTemp;
_minSteamGenOutletTemp = exchangerExitTemp;
}
/*----------------------------------------------------------------*/
/* constructor #2 */
/*----------------------------------------------------------------*/
HtfCycle::HtfCycle ( double receiverTemp ,
double storageHeight ,
double storageDiameter ,
double insulationThickness ,
double exchangerExitTemp ,
Powerblock * powerblock ,
double apertureHeight ,
double apertureWidth ,
double receiverTubesDin ,
double receiverTubesThickness ,
int receiverNbTubes ,
int timeInterval ,
double exchangerTubesDin ,
double exchangerTubesDout ,
double exchangerTubesLength ,
double exchangerTubesSpacing ,
double baffleCut ,
int nbOfBaffles ,
int exchangerNbOfTubes ,
int exchangerNbOfPassesPerShell ,
int exchangerNbOfShells ) :
// Mechanical components:
_centralReceiver ( &_centralReceiverInlet ,
&_centralReceiverOutlet,
apertureHeight ,
apertureWidth ,
insulationThickness ,
receiverTubesDin ,
receiverTubesThickness ,
receiverNbTubes ) ,
_hotStorage ( &_centralReceiverOutlet,
&_steamGeneratorInlet ,
storageHeight ,
storageDiameter ,
insulationThickness ) ,
_coldStorage ( &_steamGeneratorOutlet,
&_centralReceiverInlet,
1.2*storageHeight ,
storageDiameter ,
insulationThickness ) ,
_steamGenerator ( &_steamGeneratorInlet ,
&_steamGeneratorOutlet ,
powerblock ,
exchangerTubesLength ,
exchangerTubesDin ,
exchangerTubesDout ,
exchangerTubesSpacing ,
baffleCut ,
nbOfBaffles ,
exchangerNbOfTubes ,
exchangerNbOfPassesPerShell,
exchangerNbOfShells ) ,
// MoltenSalt conditions:
_centralReceiverInlet ( exchangerExitTemp, P_ATM, 0.0 ) ,
_centralReceiverOutlet ( receiverTemp , P_ATM, 0.0 ) ,
_steamGeneratorInlet ( receiverTemp , P_ATM, 0.0 ) ,
_steamGeneratorOutlet ( exchangerExitTemp, P_ATM, 0.0 ) ,
_timeInterval ( timeInterval ) {
_steamGenOutletMsRate.reserve ( 1440 * _timeInterval ); // 1440=24x60
_steamGenOutletTemp.reserve ( 1440 * _timeInterval );
_storageHeat.reserve ( 1440 * _timeInterval );
_minColdStorageTemp = exchangerExitTemp;
_minHotStorageTemp = receiverTemp;
_minSteamGenOutletTemp = exchangerExitTemp;
}
/*----------------------------------------------------------------------*/
/* This function generates one full iteration of the HTF cycle for */
/* a whole time interval for a given energy input. The cycle goes as: */
/* 1- Determine receiver's outlet properties (mass flow/temperature) */
/* 2- Determine inflow requirements for the steam generator */
/* 3- Determine hot storage level and temperature at interval end */
/* 4- Determine cold storage level and temperature at interval end */
/*----------------------------------------------------------------------*/
void HtfCycle::fOperateCycle ( int timeInSeconds ,
double energyFromField ,
double requiredPowerOutput ,
bool low_fid ) {
double hotMass_i, hotMass_f, hotMass_avg;
double hotTemp_i, hotTemp_f, hotTemp_avg, hotTemp_avg2;
double hotLevel_i, hotLevel_f, hotLevel_avg;
double U_i, U_f; // U_avg;
double Q_dot_i, Q_dot_avg; // Q_dot_f
double availableMass;
double hotMassFlow_in, hotMassFlow_out, hotMassFlow_out2;
double hotTemp_in, hotTemp_out;
double heatedMass;
double temperaturePrecision = 0.01 / timeInSeconds;
size_t cas, count;
int steamGeneratorModel = _steamGenerator.get_exchangerModel();
double Cp = HEAT_CAPACITY;
double minimumHotMass = 0.05*MS_DENSITY*_hotStorage.get_heightOfStorage()
*PI*pow(_hotStorage.get_diameterOfStorage() / 2.0, 2.0);
hotMassFlow_in = _centralReceiver.computeEnergyToFluid ( energyFromField );
hotMass_i = _hotStorage.get_storedMass();
Q_heat_hot = 0.0;
Q_heat_cold = 0.0;
if ( hotMassFlow_in == 0.0 && hotMass_i == 0.0 ) { cas = 1; }
else if ( hotMassFlow_in == 0.0 && hotMass_i > 0.0 ) { cas = 2; }
else if ( hotMassFlow_in > 0.0 && hotMass_i == 0.0 ) { cas = 3; }
else if ( hotMassFlow_in > 0.0 && hotMass_i > 0.0 ) { cas = 4; }
else if ( hotMassFlow_in == 0.0 && hotMass_i < 0.0 ) { hotMass_i = 0.0; cas = 1; }
else if ( hotMassFlow_in > 0.0 && hotMass_i < 0.0 ) { hotMass_i = 0.0; cas = 3; }
else {
std::ostringstream oss;
oss << "error in the full iteration of the HTF cycle: hotMassFlow_in = "
<< hotMassFlow_in << " hotMass_i = " << hotMass_i;
throw Simulation_Interruption ( oss.str() );
}
switch ( cas ) {
case 1:
hotTemp_i = 0.0;
hotLevel_i = 0.0;
hotMassFlow_out = 0.0;
availableMass = 0.0;
heatedMass = 0.0;
break;
case 2:
heatedMass = 0.0;
availableMass = hotMass_i;
hotTemp_i = _hotStorage.get_storedTemperature();
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow ( requiredPowerOutput, hotTemp_i);
else
hotMassFlow_out
= _steamGenerator.fComputeRequiredMoltenSaltMassFlow (requiredPowerOutput, hotTemp_i, availableMass / timeInSeconds);
hotLevel_i = _hotStorage.fComputeStorageLevel(hotMass_i);
U_i = hotMass_i* Cp * hotTemp_i;
Q_dot_i = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_i);
hotTemp_out = hotTemp_i;
hotMassFlow_out2 = 0.0;
if ( availableMass < timeInSeconds*hotMassFlow_out ||
availableMass - timeInSeconds*hotMassFlow_out < minimumHotMass ||
hotMassFlow_out == 0.0 ) {
hotMass_f = hotMass_i;
hotLevel_f = hotLevel_i;
hotMassFlow_out = 0.0;
hotMassFlow_out2 = 0.0;
U_f = U_i - timeInSeconds*Q_dot_i;
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
count = 0;
if ( !low_fid ) {
while ( fabs(hotTemp_avg2 - hotTemp_avg) > 0.001 && count < 15 ) {
hotTemp_avg2 = hotTemp_avg;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_i);
U_f = U_i - timeInSeconds*Q_dot_avg;
hotTemp_f = U_f / (Cp * hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
++count;
}
}
}
else {
hotMass_f = hotMass_i - timeInSeconds * hotMassFlow_out;
hotMass_avg = (hotMass_i + hotMass_f) / 2.0;
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
U_f = U_i - timeInSeconds*(hotMassFlow_out*Cp*hotTemp_out - Q_dot_i);
hotTemp_f = U_f / (Cp * hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
if ( steamGeneratorModel == 1 )
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out
= _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
count = 0;
if ( !low_fid ) {
while ((fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision ||
fabs(hotMassFlow_out2 - hotMassFlow_out) / hotMassFlow_out > 0.001) &&
count < 15) {
hotTemp_avg2 = hotTemp_avg;
hotMassFlow_out2 = hotMassFlow_out;
hotMass_f = hotMass_i - timeInSeconds*hotMassFlow_out;
hotMass_avg = (hotMass_f + hotMass_i) / 2.0;
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
U_f = U_i - timeInSeconds*(Cp*hotMassFlow_out*hotTemp_avg + Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
if ( steamGeneratorModel == 1 )
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
++count;
}
}
// Removed 2022-12-15:
// hotMassFlow_out*timeInSeconds > availableMass ? hotMassFlow_out = 0.0 : 0;
// and replaced by:
if ( hotMassFlow_out*timeInSeconds > availableMass )
hotMassFlow_out = 0.0;
hotMass_f = hotMass_i - timeInSeconds*hotMassFlow_out;
}
// Set final conditions for the flows and storage
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_avg);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
break;
case 3:
hotTemp_in = _centralReceiverOutlet.get_temperature();
hotTemp_i = hotTemp_in;
hotLevel_i = 0.0;
hotMass_i = 0.0;
availableMass = hotMassFlow_in*timeInSeconds - minimumHotMass;
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_i);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_i, availableMass / timeInSeconds);
hotMass_f = hotMass_i + timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
hotLevel_f = _hotStorage.fComputeStorageLevel(hotMass_f);
if ( timeInSeconds*hotMassFlow_in < minimumHotMass ) {
hotMass_f = 0.0;
Q_dot_avg = 0.0;
hotMassFlow_out = 0.0;
hotMass_f = timeInSeconds*hotMassFlow_in;
//thermal losses are neglected for these intervals
//Setting final conditions
_hotStorage.set_storage(hotMass_f, hotTemp_i);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
heatedMass = timeInSeconds*hotMassFlow_in;
break;
}
else if ( hotLevel_f <= _hotStorage.get_heightOfStorage() && timeInSeconds*hotMassFlow_in > minimumHotMass ) {
availableMass = timeInSeconds*hotMassFlow_in - minimumHotMass;
if (timeInSeconds*hotMassFlow_out > availableMass)
hotMassFlow_out = 0.0;
hotMass_f = timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
hotMass_avg = hotMass_f / 2.0;
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
Q_dot_i = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_avg);
U_f = timeInSeconds*(hotMassFlow_in*Cp*hotTemp_in - hotMassFlow_out*Cp*hotTemp_in - Q_dot_i);
hotTemp_f = U_f / (Cp*hotMass_f);
if ( hotTemp_f < MELTING_POINT ) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
count = 0;
if ( !low_fid ) {
while ( fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision
&& count < 15 ) {
hotTemp_avg2 = hotTemp_avg;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
U_f = timeInSeconds*(hotMassFlow_in*Cp*hotTemp_in - hotMassFlow_out*Cp*hotTemp_avg - Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i - hotTemp_f) / 2.0;
++count;
}
}
//setting final conditions
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_avg);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
heatedMass = timeInSeconds*hotMassFlow_in;
}
else if (hotLevel_f > _hotStorage.get_heightOfStorage() && hotMassFlow_out == 0.0) {
hotLevel_f = _hotStorage.get_heightOfStorage();
hotMass_f = MS_DENSITY*hotLevel_f * PI*pow(_hotStorage.get_diameterOfStorage(), 2.0) / 4.0;
U_i = hotMass_f * hotTemp_i * Cp;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_f);
U_f = U_i - timeInSeconds*Q_dot_avg;
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotMassFlow_in = 0.0;
//Setting final conditions
heatedMass = hotMass_f;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(0.0);
_steamGeneratorOutlet.set_massFlow(0.0);
break;
}
else if (hotLevel_f > _hotStorage.get_heightOfStorage()) {
hotLevel_f = _hotStorage.get_heightOfStorage();
hotMass_f = MS_DENSITY*hotLevel_f * PI*pow(_hotStorage.get_diameterOfStorage(), 2.0) / 4.0;
hotTemp_f = hotTemp_in;
hotMassFlow_in = hotMassFlow_out;
//Setting final conditions
heatedMass = hotMass_f + timeInSeconds*hotMassFlow_out;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_in);
break;
}
else if (hotMassFlow_out == 0.0) {
hotMassFlow_out = 0.0;
hotMass_f = hotMassFlow_in*timeInSeconds;
hotMass_avg = hotMass_f / 2.0;
hotLevel_f = _hotStorage.fComputeStorageLevel(hotMass_f);
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
U_i = 0.0;
Q_dot_i = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_avg);
U_f = timeInSeconds*(hotMassFlow_in*Cp*hotTemp_i - Q_dot_i);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
count = 0;
if ( !low_fid ) {
while (fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision && count < 15) {
hotTemp_avg2 = hotTemp_avg;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
U_f = timeInSeconds*(hotMassFlow_in*Cp*hotTemp_in - Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
++count;
}
}
heatedMass = hotMassFlow_in*timeInSeconds;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(0.0);
_steamGeneratorOutlet.set_massFlow(0.0);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
}
else {
hotMass_f = timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
hotTemp_f = hotTemp_i;
//losses are neglected for this time frame in this case just like in the case
//where the tank is full. The temperature of the fluid being outputed is considered
//equal to the entrance temperature.
//setting final conditions
heatedMass = timeInSeconds * hotMassFlow_in;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_f);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
break;
}
break;
case 4:
hotMass_i = _hotStorage.get_storedMass();
hotTemp_i = _hotStorage.get_storedTemperature();
hotTemp_in = _centralReceiverOutlet.get_temperature();
hotLevel_i = _hotStorage.fComputeStorageLevel(hotMass_i);
availableMass = hotMass_i + timeInSeconds*hotMassFlow_in;
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_i);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_i, availableMass / timeInSeconds);
if ( availableMass - timeInSeconds*hotMassFlow_out < minimumHotMass ) {
/*hotMassFlow_out = availableMass / timeInSeconds;*/
if (availableMass > minimumHotMass) {
hotMassFlow_out = 0.0;
hotMass_f = availableMass - timeInSeconds*hotMassFlow_out;
}
else {
hotMassFlow_out = 0.0;
hotMass_f = availableMass;
}
U_i = hotMass_i * Cp * hotTemp_i;
hotMass_avg = (hotMass_i + hotMass_f) / 2.0;
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
Q_dot_i = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_avg);
U_f = U_i + timeInSeconds*(hotMassFlow_in * Cp * hotTemp_in - hotMassFlow_out * Cp * hotTemp_i - Q_dot_i);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
count = 0;
if ( !low_fid ) {
while (fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision && count < 15) {
hotTemp_avg2 = hotTemp_avg;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
U_f = U_i + timeInSeconds*(hotMassFlow_in * Cp * hotTemp_in - hotMassFlow_out * Cp * hotTemp_avg - Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
++count;
}
}
//in this case, thermal losses will be neglected
heatedMass = timeInSeconds*hotMassFlow_in;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature((hotMass_i*hotTemp_i + hotMassFlow_in*hotTemp_in*timeInSeconds) / availableMass);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
break;
}
hotMass_f = hotMass_i + timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
hotMass_avg = (hotMass_i + hotMass_f) / 2.0;
hotLevel_f = _hotStorage.fComputeStorageLevel(hotMass_f);
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
if (hotLevel_f > _hotStorage.get_heightOfStorage()) {
hotLevel_f = _hotStorage.get_heightOfStorage();
hotMass_f = MS_DENSITY*hotLevel_f*PI*pow(_hotStorage.get_diameterOfStorage(), 2.0) / 4.0;
hotLevel_avg = hotLevel_f;
hotMass_avg = hotMass_f;
hotMassFlow_in = (hotMass_f - hotMass_i + hotMassFlow_out*timeInSeconds) / timeInSeconds;
hotTemp_in = _centralReceiverOutlet.get_temperature();
hotTemp_f = (hotTemp_i*hotMass_i + hotMassFlow_in*hotTemp_in - hotMassFlow_out*hotTemp_i) / hotMass_f;
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
hotTemp_avg2 = 0.0;
hotMassFlow_out2 = 0.0;
count = 0;
if ( !low_fid ) {
while ((fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision
|| fabs(hotMassFlow_out2 - hotMassFlow_out) / hotMassFlow_out > 0.001)
&& count < 15) {
hotTemp_avg2 = hotTemp_avg;
hotMassFlow_out2 = hotMassFlow_out;
hotMassFlow_in = (hotMass_f - hotMass_i + hotMassFlow_out*timeInSeconds) / timeInSeconds;
U_i = hotMass_i*Cp*hotTemp_i;
U_f = U_i + timeInSeconds*(Cp*hotMassFlow_in*hotTemp_in - Cp*hotMassFlow_out*hotTemp_avg - Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
++count;
}
}
hotMassFlow_out*timeInSeconds > availableMass ? hotMassFlow_out = 0. : 0;
hotMassFlow_in = (hotMass_f - hotMass_i + hotMassFlow_out*timeInSeconds) / timeInSeconds;
//setting final conditions
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_avg);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
heatedMass = hotMassFlow_in*timeInSeconds;
break;
}
hotTemp_in = _centralReceiverOutlet.get_temperature();
Q_dot_i = _hotStorage.fComputeEnergyLosses(hotTemp_i, hotLevel_avg);
U_i = hotMass_i * Cp*hotTemp_i;
U_f = U_i + timeInSeconds*(Cp*hotMassFlow_in*hotTemp_in - Cp*hotMassFlow_out*hotTemp_i - Q_dot_i);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
hotTemp_avg2 = 0.0;
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
hotMassFlow_out2 = 0.0;
count = 0;
if ( !low_fid ) {
while ((fabs(hotTemp_avg2 - hotTemp_avg) > temperaturePrecision
|| fabs(hotMassFlow_out2 - hotMassFlow_out) > 0.001)
&& count < 15) {
hotTemp_avg2 = hotTemp_avg;
hotMassFlow_out2 = hotMassFlow_out;
hotMass_f = hotMass_i + timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
hotMass_avg = (hotMass_i + hotMass_f) / 2.0;
hotLevel_avg = _hotStorage.fComputeStorageLevel(hotMass_avg);
Q_dot_avg = _hotStorage.fComputeEnergyLosses(hotTemp_avg, hotLevel_avg);
U_f = U_i + timeInSeconds*(Cp*hotMassFlow_in*hotTemp_in - Cp*hotMassFlow_out*hotTemp_avg - Q_dot_avg);
hotTemp_f = U_f / (Cp*hotMass_f);
if (hotTemp_f < MELTING_POINT) {
Q_heat_hot = (MELTING_POINT - hotTemp_f) * Cp * hotMass_f;
hotTemp_f = MELTING_POINT;
}
hotTemp_avg = (hotTemp_i + hotTemp_f) / 2.0;
if (steamGeneratorModel == 1)
hotMassFlow_out = _steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg);
else
hotMassFlow_out =
_steamGenerator.fComputeRequiredMoltenSaltMassFlow(requiredPowerOutput, hotTemp_avg, availableMass / timeInSeconds);
++count;
}
}
hotMass_f = hotMass_i + timeInSeconds*(hotMassFlow_in - hotMassFlow_out);
//Final conditions
heatedMass = hotMassFlow_in * timeInSeconds;
_hotStorage.set_storage(hotMass_f, hotTemp_f);
_centralReceiverInlet.set_massFlow(hotMassFlow_in);
_centralReceiverOutlet.set_massFlow(hotMassFlow_in);
_steamGeneratorInlet.set_massFlow(hotMassFlow_out);
_steamGeneratorInlet.set_temperature(hotTemp_avg);
_steamGeneratorOutlet.set_massFlow(hotMassFlow_out);
break;
}
//Now evaluate the cold storage
double coldTemp_i, coldTemp_f, coldTemp_avg, coldTemp_avg2;
double coldMass_i, coldMass_f, coldMass_avg;
double coldLevl_i, coldLevl_avg;
double coldMassFlow_in, coldMassFlow_out;
double coldTemp_in;
double maxColdMass;
coldMass_i = _coldStorage.get_storedMass();
coldTemp_i = _coldStorage.get_storedTemperature();
coldLevl_i = _coldStorage.fComputeStorageLevel(coldMass_i);
coldMassFlow_in = _steamGeneratorOutlet.get_massFlow();
coldMassFlow_out = heatedMass / timeInSeconds;
coldTemp_in = _steamGeneratorOutlet.get_temperature();
//preliminary approximation
coldMass_f = coldMass_i + timeInSeconds*(coldMassFlow_in - coldMassFlow_out);
// coldLevl_f = _coldStorage.fComputeStorageLevel(coldMass_f);
_coldStorage.fComputeStorageLevel(coldMass_f);
coldMass_avg = (coldMass_i + coldMass_f) / 2.0;
coldLevl_avg = _coldStorage.fComputeStorageLevel(coldMass_avg);
Q_dot_i = _coldStorage.fComputeEnergyLosses(coldTemp_i, coldLevl_i);
if (Q_dot_i < 0.0)
Q_dot_i = 0.0;
U_i = coldMass_i * Cp * coldTemp_i;
U_f = U_i + timeInSeconds*(coldMassFlow_in*Cp*coldTemp_in - coldMassFlow_out*Cp*coldTemp_i - Q_dot_i);
coldTemp_f = U_f / (Cp*coldMass_f);
coldTemp_avg = (coldTemp_i + coldTemp_f) / 2.0;
coldTemp_avg2 = 0.0;
count = 0;
if ( !low_fid ) {
while ( fabs(coldTemp_avg2 - coldTemp_avg) > temperaturePrecision && count < 15) {
coldTemp_avg2 = coldTemp_avg;
Q_dot_avg = _coldStorage.fComputeEnergyLosses(coldTemp_avg, coldLevl_avg);
U_f = U_i + timeInSeconds*(coldMassFlow_in*Cp*coldTemp_in - coldMassFlow_out*Cp*coldTemp_avg - Q_dot_avg);
coldTemp_f = U_f / (Cp*coldMass_f);
if (coldTemp_f < MELTING_POINT) {
Q_heat_cold = (MELTING_POINT - coldTemp_f) * Cp * coldMass_f;
coldTemp_f = MELTING_POINT;
}
coldTemp_avg = (coldTemp_i + coldTemp_f) / 2.0;
++count;
}
}
maxColdMass = _coldStorage.get_heightOfStorage() *
PI * pow(_coldStorage.get_diameterOfStorage()/2.0,2.0) * MS_DENSITY;
coldMass_f = maxColdMass - _hotStorage.get_storedMass();
_coldStorage.set_storage(coldMass_f, coldTemp_f);
// Data gathering:
_steamGenOutletMsRate.push_back( _steamGeneratorOutlet.get_massFlow() );
_steamGenOutletTemp.push_back ( _steamGeneratorOutlet.get_temperature() );
if (_hotStorage.get_storedTemperature() != 0.0
&& _hotStorage.get_storedTemperature() < _minHotStorageTemp)
_minHotStorageTemp = _hotStorage.get_storedTemperature();
if (_coldStorage.get_storedTemperature() != 0.0
&& _coldStorage.get_storedTemperature() < _minColdStorageTemp)
_minColdStorageTemp = _coldStorage.get_storedTemperature();
if (_steamGeneratorOutlet.get_temperature() < _minSteamGenOutletTemp)
_minSteamGenOutletTemp = _steamGeneratorOutlet.get_temperature();
_storageHeat.push_back(Q_heat_cold + Q_heat_hot);
}
/*--------------------------------------------*/
void HtfCycle::initiateColdStorage ( void ) {
/*--------------------------------------------*/
double volume = PI*pow(_coldStorage.get_diameterOfStorage() / 2.0, 2.0)*_coldStorage.get_heightOfStorage();
double storedMass = volume * MS_DENSITY;
double storedTemperature = _minColdStorageTemp;
_coldStorage.set_storage(storedMass, storedTemperature);
}
/*---------------------------------------------------------------------------------*/
void HtfCycle::setStorage ( double percentHot, double tempHot, double tempCold ) {
/*---------------------------------------------------------------------------------*/
double H = _hotStorage.get_heightOfStorage();
double cold_H = _coldStorage.get_heightOfStorage();
_hotStorage.set_storage2(H*(percentHot / 100.0), tempHot);
_coldStorage.set_storage2(cold_H - (H*percentHot / 100.0), tempCold);
}