[Equest-users] 90.1 App G Fan Power and EER Calculations

[Steve Burley]

I'm sure this must have been asked before but I cannot find an answer in the archives - if there is one please point me to it.

I have interpreted the requirements of 90.1, App. G to split the EER of cooling equipment with a supply fan into its components to model the fan energy separately as follows:


1.       Say a space has a cooling load of 80,000Btu/h and the system is packaged single zone, EER - 11.2.

2.       Calculate airflow for 20°F temperature difference - 3708cfm

3.       Calculate fan bhp from Table G3.1.2.9 - 3.49bhp

4.       Calculate fan power as per G3.1.2.9 - 2972W

5.       Calculate gross input power from load and EER - 7143W

6.       Subtract 4 from 5 for compressor/condenser input power - 4171W

7.       Convert to EIR - 0.1779

This appears to make sense from reading App. G but ends up with high fan power consumption and low space cooling loads. Am I wrong here?

Thanks,

Steven Burley


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