Issue Warning Error on negative coil capacity sizing #11197
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…ative-coil-capacity-sizing
…ative-coil-capacity-sizing
| int constexpr SpeedCal{1}; | ||
| VariableSpeedCoils::InitVarSpeedCoil(*state, DXCoilNum, SensLoad, LatentLoad, fanOp, OnOffAirFlowRatio, SpeedRatio, SpeedCal); | ||
| EXPECT_TRUE(compare_err_stream_substring("entering air temperature is less than design outlet air temperature", true)); | ||
| EXPECT_TRUE(compare_err_stream_substring("This will yield negative coil capacity sizing", true)); |
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This unit test should fail. The old message used "will" and the new warning message above uses:
This would yield negative coil capacity sizing
| format("On design day {}, cooling coil entering air temperature {:.2R} is less than design supply air temperature {:.2R}. This would " | ||
| "yield negative coil capacity sizing for {}.", state.dataSize->FinalSysSizing(state.dataSize->CurSysNum).CoolDesDay, MixTemp, SupTemp, varSpeedCoil.Name)); | ||
| ShowContinueError(state, "Cooling capacity is set to zero during sizing; simulation continues."); | ||
| } |
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Coil sizing is based on enthalpy. Given the sneaky use of a standard capacity if enthalpies are not correct CoilCapAtPeak should never be negative here. I would like to see the 48000 removed (i.e., delete the else) since it just forces a non-zero coil capacity. There is nothing wrong with the coil sizing to 0 if FinalSysSizing conditions warrant that result.
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Yes! Not knowing where it came from, I was reticent to touch a "magic number."
tanaya-mankad
changed the title
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Our main energy modeler, Aaron, suggested that the client might like an even fuller description of the air state that causes a negative capacity, in the vein of this code, even though the eventual coil size = 0 will be valid. |
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@tanaya-mankad that would be a good fix for this issue. |
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Pull request overview
Description of the purpose of this PR
A client using a proprietary model in E+23.1 noticed that when the design day temperature was cooler than the cooling coil supply temperature, the simulation crashed. This behavior was inadvertently circumvented by a pre-condition check in the DXCoils CBF calculation, that exits early if airflow or total capacity are zero. However, the user is never warned that an input condition caused a negative total capacity to be calculated, which was then zeroed out for safety.
This PR creates a Severe Error to indicate the inverted temperature condition.
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