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Why Does the Air-Cooled Chiller Show a Higher COP Than the Water-Cooled One?

I'm comparing the COP of air-cooled and water-cooled chillers using the COMNET EIRFPLR curves

I plotted both chillers' COP using Desmos for both scroll type chillers:

image description

Given that both chillers have the same nominal COP (1 in this case), I expected the water-cooled chiller to perform better. However, the curve suggests that the air-cooled chiller has a higher COP across all part-load conditions.

This seems counterintuitive since water-cooled chillers are generally known to be more efficient. Am I misunderstanding something about the EIRFPLR curves, or is there another explanation for this result?

I want with this post suggestion for converting EIRFPLR to COP using this post

Would love to hear your insights! 🚀