[Equest-users] Cooling EIR

Daniel Kaler DanielK at mepassociates.com
Tue Feb 7 10:39:15 PST 2012


Hi All,

I don't mean to ask questions back to back days here, but I ran into roadblock. I found an equation for the compressor EIR to be:

Cooing EIR=(1/EER-0.012167)/(1/3.413-0.012167)

Has anyone tried to derive this, or know of a document that has done so? I seem to be missing something in my derivation as follows:


*         EER=Cooling Output (Btuh)/(Supply Fan Input (W) + Compressor Input (W))

*         1/EER=Supply Fan Input/Cooling Output + Compressor Input/Cooling Output

*         Compressor Input/Cooling Output = 1/EER - Supply Fan Input/Cooling Output

At ARI condition supply fan is rated at 365W/CFM & 400CFM/Ton
So Supply Fan Input/Cooling Output = 0.146 kW/Ton or .012167 W/Btuh


*         Compressor Input/Cooling Output = 1/EER - 0.012167


*         Compressor Input/Cooling Output (Btu/Btu) = 3.413*(1/EER - 0.012167)

i.e.

EER=11
Compressor EIR = 3.413*(1/11 - 0.012167) = 0.2687 (should be 0.2580)

Is there something that I am missing?

Thank in advance,

Daniel Kaler
Energy Engineer, EIT


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