Fix 10168 zone multiplier incorrectly applies to water heater tank losses #11240
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…lies-to-water-heater-tank-losses
…lies-to-water-heater-tank-losses
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@mjwitte this looks OK to me, but I'd defer to you on it. |
| if (state.dataHeatBal->Zone(ZoneNum).numSpaces > 1) { | ||
| gainFrac = state.dataHeatBal->space(spaceNum).FloorArea / state.dataHeatBal->Zone(ZoneNum).FloorArea; | ||
| } | ||
| if (std::find(AdjustTankLossMultipliers.begin(), AdjustTankLossMultipliers.end(), IntGainCompType) != AdjustTankLossMultipliers.end()) { |
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The method here is sound, but a comment line to explain would be helpful here.
But should this be done at the space level instead of here? At this point, only zone-level internal gain types call SetupSpaceInternalGain directly, so no multiplier adjustment is necessary. However, if at some point in the future the tank loss allows specifying a Zone Name or Space Name, then this adjustment will not get applied.
I think it would be better to move this into SetupSpaceInternalGain.
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Added a comment and moved to SetupSpaceInternalGain
| gainFrac = state.dataHeatBal->space(spaceNum).FloorArea / state.dataHeatBal->Zone(ZoneNum).FloorArea; | ||
| } | ||
| if (std::find(AdjustTankLossMultipliers.begin(), AdjustTankLossMultipliers.end(), IntGainCompType) != AdjustTankLossMultipliers.end()) { | ||
| int multiplier = state.dataHeatBal->Zone(ZoneNum).Multiplier * state.dataHeatBal->Zone(ZoneNum).ListMultiplier; |
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Nit picking, this can be const
| int RetNodeNum = 0 // for return air heat gains | ||
| ); | ||
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| // Multipliers are double counted for tank losses - these are the internal gains that need adjust for this |
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It's not that the multipliers are double counted, but rather the loss should be distributed across the multiplied zones/spaces. Not sure how to say that more simply.
| static constexpr std::array<DataHeatBalance::IntGainType, 4> AdjustTankLossMultipliers = { | ||
| DataHeatBalance::IntGainType::WaterHeaterMixed, | ||
| DataHeatBalance::IntGainType::WaterHeaterStratified, | ||
| DataHeatBalance::IntGainType::ThermalStorageChilledWaterMixed, | ||
| DataHeatBalance::IntGainType::ThermalStorageChilledWaterStratified}; |
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If I'm following this correctly, any gain that comes from HVAC, electrical, refrigeration, etc. (anything other than the zone gains like lights, people, etc) should be included in this list. @shorowit ?
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I did it this way so we could easily add/remove other gains as needed, but beyond water heaters I wasn't sure what to add.
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I guess this is because the tanks have an ambient zone specified, right?
Doing a quick search for "Ambient Temperature Zone Name" in the IDD shows the following components:
Chiller:Electric:ASHRAE205
WaterHeater:Mixed
WaterHeater:Stratified
ThermalStorage:ChilledWater:Mixed
ThermalStorage:ChilledWater:Stratified
ThermalStorage:HotWater:Stratified
Pipe:Indoor
Searching "Ambient Zone Name" shows these:
ZoneHVAC:ForcedAir:UserDefined
AirTerminal:SingleDuct:UserDefined
Coil:UserDefined
PlantComponent:UserDefined
Duct:Loss:Conduction
Do these get handled here too?
Also, we can put a 📌 in this, but we should probably unify these.
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I'll try to test these out and see if any should be added to the list.
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Opened #11365 to address other components with ambient temperature zones
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@mitchute , we'd like to prevent this PR from expanding in complexity more than the Issue it was created to resolve, so there's a new issue documenting your concerns so we don't lose track of them. In the meantime, this particular set of changes is ready to finalize.
…lies-to-water-heater-tank-losses
…lies-to-water-heater-tank-losses # Conflicts: # tst/EnergyPlus/unit/WaterThermalTanks.unit.cc
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@kevin-moos it has been 28 days since this pull request was last updated. |
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Pull request overview
Description of the purpose of this PR
Fix a defect in which zone multipliers are incorrectly applied to water heater tank losses. Add unit test to show correctly adjusted space gain fraction.
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