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Railways NTPC (Technical Ability) Refrigeration and Air-Conditioning Question Bank Refrigeration and Air-Conditioning

  • question_answer
    A refrigerating machine in heat pump mode has a C.O.P. of 4. If it is worked in refrigerating mode with a power input of 3 kW, what is the heat extracted from the food kept in a refrigerator?

    A) 180 kJ/min                    

    B) 360 kJ/min

    C) 540 kJ/min                    

    D) 720 kJ/min

    Correct Answer: C

    Solution :

    \[{{(COP)}_{HP}}=4\] \[{{(COP)}_{\text{Ref}}}={{(COP)}_{HP}}-1=4-1=3\]             \[\frac{Q}{W}=\frac{Q}{3}\] \[Q=9\,kW\,\,or\,\,540\,kJ/min\]


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