What is COP in refrigeration and how is it calculated?

COP (Coefficient of Performance) measures the efficiency of a refrigeration system, defined as the ratio of desired cooling effect to the work input. For a refrigerator, COP = Qc/W where Qc is heat removed from cold space and W is compressor work. For a heat pump, COP = Qh/W where Qh is heat delivered to hot space. Higher COP indicates better system efficiency, with typical values ranging from 2-6 for air conditioners.