Limitations of Carnot Vapor Compression Systems:
Though in theory, the Carnot vapour compression cycle contain the highest COP; this is not appropriate for use in practical refrigeration systems. It is because this is virtually not possible to compress the refrigerant isothermally from state 2 to state 3 in a fixed time interval. To offset this complexity, we may follow the alternate path 1'-3-4-5. Although, this results in other problems.