Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
A couple of thoughts: 1) EER and COP do NOT affect loads. They affect the energy used to meet the loads. eg, the building cooling load (amount of cooling required) might be 100kW. The electric power needed by a chiller (COP = 3) to meet that load is 100/3 = 33.3 kw.
2) The conversion of chiller COP to EER is simple - as mentioned by Luis. For "packaged" equipment (fan, compressor, coil, condenser all in one piece of equipment), the USA rating agency (AHRI) defines the EER as a composite efficiency that includes compressor power AND fan power. Fan power, however, is assumed to be at a standard laboratory condition and normally is NOT the same as the actual fan power.
Confusing? Yes :)
For DX coils (those used in packaged equipment), E+ conveniently does the math to derive the manufacturer's EER for you in the background, but YOU must derive the compressor-only EER (which is what E+ uses), since the manufacturer uses the composite AHRI value. This is not too difficult once you understand the background assumptions made by AHRI. It's very helpful to have the calculations represented in a spreadsheet and I know that many modelers have done this.
If you would like my version of such a spreadsheet, please message me privately and I'll be happy to share it.
ps, kudos to you for working to understand the underlying assumptions!
