(a) A reversible heat pump is used to maintain a temperature of 0c in a refrigerator when it rejects the heat to the surroundings at 25c. If the heat removal rate from the refrigerator is 1440 kj/min, determine the C.O.P. of the machine and work input required.
(b) If the required input to run the pump is developed by a reversible engine which receives heat at 380c and rejects heat to atmosphere, then determine the overall C.O.P. of the system.