There any many references that say COP improves with superheat in some gases and not in others. R12 was classically described as an improver with SH whilst R22 was said to have worse COP values as SH increased.

So far I have not been able to show this increase in COP and so ask if anyone knows of a good example/article that descibes it.

All I have seen is that SH pushes the compression cycle into flatter entropy zones and hence greater compression work plus it reduces the compressor efficiencies and both are bad for COP.

Also as SH increases so the quality increases which reduces the refrigeration effect. Combine all 3 effects and COP falls of very quickly with SH.

Thanks

Chef