Consolidate code in CorrectZoneHumRat #6415
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…Remove-a-section-with-ZoneMassFlowRate
| A = AirflowNetworkExchangeData( ZoneNum ).SumMHr + AirflowNetworkExchangeData( ZoneNum ).SumMMHr + SumHmARa( ZoneNum ); | ||
| } | ||
| C = RhoAir * Zone( ZoneNum ).Volume * Zone( ZoneNum ).ZoneVolCapMultpMoist / SysTimeStepInSeconds; | ||
| ZoneOABal = MDotOA( ZoneNum ); |
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What is MDotOA? I only see it used in the moisture prediction/correction, but I don't find it in the temperature calculations.
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@mjwitte MDotOA is defined as Airbalance MASS FLOW rate in DataHeatBalFanSys, The equivalent item of MDotOA in the temperature calculation is MDotCPOA defined as Airbalance MASS FLOW * AIR SPECIFIC HEAT.
In order to avoid large differences in an example file, the following two lines of correction are used:
ZoneOABal = MDotOA( ZoneNum );
if ( ZoneMassFlowRate <= 0.0 ) ZoneOABal = 0.0;
However, the temperature calculation uses MDotCPOA as is without modification. Therefore, in order to be consistent with energy calculation, the correct may be removed.
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@lgu1234 I still don't understand what "Airbalance mass flow rate" is. Where does it come from?
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@mjwitte Let me dig deeper to find out "MDotOA".
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@mjwitte "MDotOA" is calculated with Air Balance Method = Quadrature in the ZoneAirBalance:OutdoorAir. It should be independent of ZoneMassFlowRate and calculated every time step. Therefore, the code in temperature calculation is correct, while the following two lines should be removed in moisture calculation, even though large differences are observed in SingleFamilyHouse_TwoSpeed_ZoneAirBalance.idf:
ZoneOABal = MDotOA( ZoneNum );
if ( ZoneMassFlowRate <= 0.0 ) ZoneOABal = 0.0;
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@lgu1234 Thanks. I forgot about that feature. I would be good to expand the comment for MDotOA where it's declared. Please go ahead and make this correction and remove the unused variables than I'll give it one final review.
| @@ -4682,6 +4682,7 @@ namespace ZoneTempPredictorCorrector { | |||
| int ADUNum; | |||
| int ADUInNode; | |||
| int ADUOutNode; | |||
| Real64 ZoneOABal; | |||
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Looks like ExhMassFlowRate and TotExitMassFlowRate (a few lines up) are not used for anything. Can these be deleted?
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@mjwitte If you agree with my changes, I will remove these two variables: ExhMassFlowRate and TotExitMassFlowRate.
I also notice that this issue also happens in CorrectZoneContaminants of the ZoneContaminantPredictorCorrector module.
mjwitte
changed the title
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@mjwitte The equivalent section is located in CalcZoneSums. Theoretically, the code after cleanup should not show differences. However, some calculations entered the section with MassFlowRate <=0. This should not happen. Therefore, if we use consistent code in both moisture and temperature, we may see some differences, but the revision is correct. |
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@mjwitte I uploaded the branch a while ago. Here is what I have done:
Test run shows differences in SingleFamilyHouse_TwoSpeed_ZoneAirBalance as expected. It is ready for final review. |
Pull request overview
Addresses #6233. Remove a surplus section of code for ZoneMassFlowRate <= 0.0 in moisture balance equation. The coefficient calculations in moisture balance equation are consistent with energy balance equation.
Small differences are found for an example file of GSHP-GLHE-CalcGFunctions.idf in local computer runs.
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