Source side outlet tempearture calculation uses loadside heat tranfer rate #10628
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This code change impacts the water source heat pump performance. It uses the source heat transfer to determine the source side outlet temperature and the PLR adjustment calculation. I've included below a sample of cooling mode operation parameters plots to show the impact of the change. This change increased the cooling mode heater transfer (due to the addition of the power term) used to determine the source side outlet temperature. Hence, the cooling PLR or the cycling ratio is decreased to limit the source side outlet temperature at the user-specified limit of 50.0C. The Cycling Ratio was reduced since the heat pump operates at the minimum PLR. Where the Cycling Ratio was reduced, the load and source side outlet temperatures were also reduced. Compared to the developed branch, this branch's source side outlet temperature is well aligned with the user-specified source side maximum temperature limit of 50C.
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In heating mode, it is the opposite; the source side heat transfer rate is less than the load side by the amount of electric power usage rate. I've included below a sample of plots of heating mode operation parameters to show the impact of the change. This change decreases the heating mode source side heater transfer rate (due to the subtraction of the power term) used to determine the source side outlet temperature. Hence, a higher heating PLR can be tolerated before it exceeds the user-specified source side temperature limit. Where the branch's PLR exceeded the developed branch's PLR, source-side outlet temperatures are within the limit but lower than the Develop branch values. This branch's source side outlet temperature behaves as expected and never undershoots or overshoots the user-specified source side temperature limits of 2C/25C while sometimes delivering slightly higher hot water temperature.
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| @@ -486,13 +486,18 @@ void EIRPlantLoopHeatPump::calcAvailableCapacity(EnergyPlusData &state, Real64 c | |||
| } | |||
| } | |||
| if (this->heatRecoveryHeatPump) { | |||
| this->calcLoadSideHeatTransfer(state, availableCapacity); | |||
| this->calcPowerUsage(state); | |||
| Real64 sourceSideHeatTransfer = this->calcQsource(availableCapacity * partLoadRatio, this->powerUsage); | |||
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Adds the steps required to calculate the power usage so that the source side heat transfer is estimated correctly.
| Real64 const sourceMCp = this->sourceSideMassFlowRate * CpSrc; | ||
| Real64 const tempSourceOutletTemp = | ||
| this->calcSourceOutletTemp(this->sourceSideInletTemp, (availableCapacity * partLoadRatio) / sourceMCp); | ||
| Real64 const tempSourceOutletTemp = this->calcSourceOutletTemp(this->sourceSideInletTemp, sourceSideHeatTransfer / sourceMCp); | ||
| if (this->EIRHPType == DataPlant::PlantEquipmentType::HeatPumpEIRHeating && tempSourceOutletTemp < this->minSourceTempLimit) { |
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The source side outlet temperature is calculated using the source side heat transfer rate.
| EXPECT_NEAR(1672.07, thisCoolingPLHP->sourceSideHeatTransfer, 0.01); | ||
| EXPECT_NEAR(50.0, thisCoolingPLHP->sourceSideOutletTemp, 0.01); | ||
| } | ||
| } |
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Added a unit test to demonstrate the impact of the code changes.
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The code change impacted one example file only and the diffs are in the |
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OK, I'm buying it, this is a good addition. Thanks @Nigusse, merging. |
Pull request overview
NOTE: ENHANCEMENTS MUST FOLLOW A SUBMISSION PROCESS INCLUDING A FEATURE PROPOSAL AND DESIGN DOCUMENT PRIOR TO SUBMITTING CODE
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