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Incorrect accounting for zone multipliers in the Outdoor Air Details report #10799

Open mdahlhausen opened 1 month ago

mdahlhausen commented 1 month ago

Issue overview

When zone multipliers are used with zone multipliers, incorrect values show up in the Mechanical Ventilation Parameters by Zone table in the Outdoor Air Details Report. This may only be occurring for some, not all system types.

In this example model DOAS_WSHP_multipliers.zip, CORE_MID ZN (and other MID zones) have a zone multiplier of 10. CORE_MID ZN has the same load assumptions as CORE_BOTTOM ZN and CORE_TOP ZN. CORE_BOTTOM ZN and CORE_TOP ZN have a zone multiplier of 1.

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Average Number of Occupants,Nominal Number of Occupants,Zone Volume [m3], and Zone Area are the same for all CORE zones. Design Zone Outdoor Airflow - Voz [m3/s] and Minimum Dynamic Target Ventilation - Voz-dyn-min [m3/s] are different, apparently already accounting for the zone multiplier. In the Total Facility line, the MID zone multipliers are applied again to calculate the total, giving incorrect totals for Design Zone Outdoor Airflow - Voz [m3/s] and Minimum Dynamic Target Ventilation - Voz-dyn-min [m3/s]. The code here fails to account for the zone multipliers already being included in the total.

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Checklist

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mjwitte commented 1 month ago

@mdahlhausen It might be useful to add a column for zone multiplier to help keep things clear. Would you prefer to see the last two columns report the values with or without multipliers?

mdahlhausen commented 1 month ago

The tables in the Outdoor Air Summary Report has a footnote on the tables: "Values shown for a single zone without multipliers". For the Outdoor Air Details tables I think a good option would be to show the values without zone multipliers, add the footnote "Values shown for a single zone without multipliers", and then add a column of zone multipliers.

mdahlhausen commented 3 weeks ago

This appears to be impacting the Zone Sensible Cooling and Zone Sensible Heating tables as well. The User Design Load is accounting for the zone multiplier in the numerator by not the denominator.