In case of engine the performance is judged the EFFICIENCY of the engine. That is – Efficiency = WORK Done / Heat Supplied .

And in case of REFRIGERATION the process is first reversed that is we have to supply work to obtain lower temperature or say for that removal of heat. Thus performance of refrigeration is just reversed . That is – N/W

Where – N = The rate of heat ABSTRACTED from the body in given time technically called “Net Refrigeration Effect” and W = Work Done .

Thus COP = Net Refrigeration Effect / Work Done Supplied . This is Called Theoretical COP .

In case of engine the performance is judged the efficiency of the engine. That is – Efficiency = Work Done / Heat Supplied .

And in case of refrigeration the process is first reversed that is we have to supply work to obtain lower temperature or say for that removal of heat. Thus performance of refrigeration is just reversed . That is – N/W

Where – N = The rate of heat abstracted from the body in given time technically called “Net Refrigeration Effect” and W = Work Done .

Thus COP = Net Refrigeration Effect / Work Done Supplied . This is Called Theoretical COP .