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LEED Baseline G3.1.2.1: EER and COP with fan energy

asked 2018-03-16 04:35:56 -0500

Gio gravatar image

updated 2018-03-16 04:37:21 -0500

Hi, I'm trying to break down the fan power from the System 4 performance. I've read this answer:

I use the Ashrae 2007 SI edition and if I use the following data (as an example): Cooling 39 kW (autosize) so I consider a power of 40 kW that is 136486 btu/h Considering the table 6.8.1B I have a COP of 3.16 (as of 1/1/2010)

I apply the formula: 7.8410^-8EERQ+0.338EER = 7.8410^-83.16136486+0.3383.16 = 1.10

So I get a COP of 1,10 that seems very low. Is there a mistake? Is it correct to level up the cooling power to the higher interval (39 kW to 40 kW)?

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answered 2018-03-20 09:11:46 -0500

updated 2018-03-20 09:15:08 -0500

The issue is the use of the COP where the expression requires EER. Using the COP of 3.16 you reference, that is an EER of 10.78. NOTE: my IP 90.1-2007 has slightly different EER ratings than what you are referencing. It has EER= 10.6 which is a COP of 3.1067. Minor, but may impact answer.

COP_nfcooling = 7.84e-8(10.78)*(136480)+0.338(10.78) = 0.115 + 3.644 = 3.759 where "nf" = no fan I believe.

Unsure why you bumped the cooling capacity from 39 kW to 40kW. any reason?

The expressions in the post you linked from @"Anna Osborne Brannon" should work for the heating COP as well.

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Hi, finally I solved it using an IP 90.1 version I found, but I was not sure about the result. I got the same results as yours and now I'm sure about it, thank you!

About bumping the capacity from 39 to 40, I just found it in this document ( page 39: the reason why is not explained, so I think I won't do it.

Gio gravatar image Gio  ( 2018-03-21 10:05:40 -0500 )edit

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Asked: 2018-03-16 04:35:56 -0500

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Last updated: Mar 20 '18