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