Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    8
    ReputationRep:
    A refrigerator is designed to make ice at –10 °C from water initially at room temperature.The energy needed to make 1.0 kg of ice at –10 °C from water initially at room temperatureis 420 kJ. The refrigerator has a coefficient of performance of 4.5.
    (i) Calculate the power input to the refrigerator if it is required to make 5.5 kg of iceevery hour.

    ii) Calculate the rate at which energy is delivered to the surroundings of the refrigerator.

    For i) I think that the energy required to cool the ice is 420 x 103 x 5.5 = 2.31 x 106. Coefficient of performance = 4.5 and COP = Qout / Work done to cause the heat transfer.

    Is Qout the energy required to cool the ice down, if so then I I assume I just divide Qout by the COP and divide by 3600.

    For ii) Can I do Qin = Qout + Work done and divide the answer by 3600

    thanks
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Are unpaid trial work shifts fair?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.