Sizing:System fixes and docs updates#11431
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| \paragraph{Field: Fraction of Autosized Heating Design Capacity}\label{field-fraction-of-autosized-heating-design-capacity} | ||
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| Enter the heating capacity as a fraction of the autosized heating capacity. This input field is required when the Heating Design Capacity Method is \emph{FractionOfAutosizedHeatingCapacity}. This input field may be left blank if a heating coil is not included in the zone HVAC equipment or the Heating Design Capacity Method is not \emph{FractionOfAutosizedHeatingCapacity}. The program calculates the heating capacity from the design autosized cooling capacity and user specified fraction. Design day sizing run must be specified. | ||
| Enter the heating capacity as a fraction of the autosized heating capacity. This input field is required when the Heating Design Capacity Method is \emph{FractionOfAutosizedHeatingCapacity}. This input field may be left blank if a heating coil is not included in the zone HVAC equipment or the Heating Design Capacity Method is not \emph{FractionOfAutosizedHeatingCapacity}. The program calculates the heating capacity from the design autosized heating capacity and user specified fraction. Design day sizing run must be specified. |
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"Heating", right?
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It does appear this word should be heating, however, heat pumps, if both coils are DX, size the heating coil based on cooling coil size. It's probably OK like this because the HP heating capacity would be based on cooling capacity, and the heating capacity would be multiplied by this fraction. So I guess leave as-is.
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@rraustad By as-is, you mean leave these fields as "... The program calculates the heating capacity from the design autosized cooling capacity and user specified fraction. ..."?
| \paragraph{Field: Fraction of Autosized Cooling Design Capacity}\label{field-fraction-of-autosized-cooling-design-capacity-1} | ||
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| Enter the cooling capacity as a fraction of the autosized cooling capacity. This input field is required when the Cooling Design Capacity Method is \emph{FractionOfAutosizedCoolingCapacity}. This input field may be left blank if a cooling coil is not included in the zone HVAC equipment or the Cooling Design Capacity Method is not \emph{FractionOfAutosizedCoolingCapacity}. The program calculates the cooling capacity from the design autosized cooling capacity and user specified fraction. Design day sizing run must be specified. | ||
| Enter the cooling capacity as a fraction of the autosized cooling capacity. This input field is required when the Cooling Design Capacity Method is \emph{FractionOfAutosizedCoolingCapacity}. This input field may be left blank if a cooling coil is not included in the airloop or the Cooling Design Capacity Method is not \emph{FractionOfAutosizedCoolingCapacity}. The program calculates the cooling capacity from the design autosized cooling capacity and user specified fraction. |
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None of the other fields had "Design day sizing run must be specified"; copy-paste error?
(This is Sizing:System. Should it mirror DesignSpecification:ZoneHVAC:Sizing?)
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Not a copy-paste error. An autosized value cannot be calculated without a sizing run. The field above for Cooling Design Capacity Per Floor Area doesn't need a sizing run because floor area would already be known.
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Sorry, I meant copy-paste error from DesignSpecification:ZoneHVAC:Sizing -> Sizing:System.
But based on your response, it sounds like we should add "Design day sizing run must be specified." to the following fields for Sizing:System:
- Cooling Design Capacity
- Fraction of Autosized Cooling Design Capacity (already has it)
- Heating Design Capacity
- Fraction of Autosized Heating Design Capacity
| \paragraph{Field: Fraction of Autosized Heating Design Capacity}\label{field-fraction-of-autosized-heating-design-capacity-1} | ||
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| Enter the heating capacity as a fraction of the autosized heating capacity. This input field is required when the Heating Design Capacity Method is FractionOfAutosizedHeatingCapacity. This input field may be left blank if heating coil is not included in the airloop or the Heating Design Capacity Method is not FractionOfAutosizedHeatingCapacity. The program calculates the heating capacity from the design autosized cooling capacity and user specified fraction. | ||
| Enter the heating capacity as a fraction of the autosized heating capacity. This input field is required when the Heating Design Capacity Method is \emph{FractionOfAutosizedHeatingCapacity}. This input field may be left blank if a heating coil is not included in the airloop or the Heating Design Capacity Method is not \emph{FractionOfAutosizedHeatingCapacity}. The program calculates the heating capacity from the design autosized heating capacity and user specified fraction. |
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"Heating", right?
| bool errorsFound = false; | ||
| HeatingCapacitySizer sizerHeatingCapacity; | ||
| sizerHeatingCapacity.overrideSizingString(SizingString); | ||
| state.dataSize->DataFracOfAutosizedHeatingCapacity = heatingCapacityMultiplier; |
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Variable heatingCapacityMultiplier was suspiciously assigned but unused previously.
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It appears you have validated this with the airflow network example file so this should be OK. It's just that I am very careful where/how these Data* global variables are used. This does seem correct.
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I did some local testing using AirflowNetwork_MultiZone_House_OvercoolDehumid.idf (which contains both AirLoopHVAC:UnitaryHeatCool and Sizing:System objects), and indeed this bugfix seems to do what we want: Nominal Heating Capacity for AirLoopHVAC:UnitaryHeatCool now takes into account However, it doesn't appear any of the existing unit or regression tests cover this particular situation. Is local testing enough, or should I introduce a new unit test or sample file? |
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A unit tests is probably preferred, though if you're able to modify the AirflowNetwork_MultiZone_House_OvercoolDehumid.idf test file without sacrificing other aspects, then that may also be an option. |
…d.idf so we can test Sizing:System autosized heating fraction with AirLoopHVAC:UnitaryHeatCool.
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…design day sentence for applicable Sizing:System fields.
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Pull request overview
AirLoopHVAC:UnitaryHeatCool#10292.Description of the purpose of this PR
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