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Which measure provides me with the HVAC electrical consumption per hour for each thermal zone separately?

asked 2021-06-28 12:27:00 -0500

gspiridakis gravatar image

updated 2021-07-09 17:46:38 -0500

Hi, i am using Open Studio and modeling a pretty big building containing about 40 thermal zones. I have found a measure called "Facility Total HVAC Electric Demand Power" which gives me the HVAC consumption of the building as a whole, hourly in Watts. I can't seem to find a measure that gives me exact that but for each thermal zone separately.

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answered 2021-06-28 17:28:59 -0500

sashadf1 gravatar image

updated 2021-06-28 17:37:39 -0500

There is a similar issue in this question response by @Keigo.

"if you want to model the multiple zone and calculate each zone bill later, then you can utilize Zone Air System Sensible Heating Energy and Zone Air System Sensible Cooling Energy in order to calculate the percentage of energy use for each zone....Cooling Coil Electricity Energy (Fan energy too?) needs to be prorated according to the proportion of energy consumption in each zone because the model has only one heat source each for heating and cooling (Furnace for heating and DX Coil for cooling). For central HVAC system, energy fuels (Electricity and NaturalGas) are not consumed in zones, but consumed in the heat source. If you want to charge the consumed energy to each zone, the consumed energy needs to be prorated according to the proportion of energy distributed to each zone. If there are three zones (Zone A, B and C).

Zone A:Cooling Electricity Energy [J] = Cooling Coil Electricity Energy [J] × Zone A:Zone Air System Sensible Cooling Energy / (Zone A:Zone Air System Sensible Cooling Energy + Zone B:Zone Air System Sensible Cooling Energy + Zone C:Zone Air System Sensible Cooling Energy)"

This example is for three zones, but you could apply the same equation and extrapolate to 40 conditioned zones.

Are all 40 conditioned thermal zones in parallel on the supply side of the HVAC system, connected to the same demand side loop that is providing the conditioning equipment (coils, fan etc.)? If not, this equation would not apply. This may not apply for the given HVAC system you are using. Can you post your node diagram from OpenStudio?

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The default results summary that Open Studio provides, mentions the annual electricity consumption of each thermal zone so percentages were not a trouble to find. All i wanted to know was the electrical consumption of the HVAC system hourly for every single zone individually so i can understand better when and why the HVAC system is working and the correlation between HVAC consumtion per hour and indoor temperature per hour for each thermal zone.

The measures that you mentioned are the ones that i am looking for though. Thanks for the quick reply.

gspiridakis gravatar image gspiridakis  ( 2021-06-28 18:26:52 -0500 )edit

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Asked: 2021-06-28 12:27:00 -0500

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Last updated: Jun 28