A domestic refrigerator is rated to remove heat continuously from the food compartment.
(i) The refrigerator operates with a coefficient of performance of 2.5. If the same machine is run in reverse so that it delivers heat to the kitchen air, calculate its COP as a heat pump.
(ii) While running as a refrigerator it extracts 1.2×105J of heat per minute from the food compartment. Determine the mechanical power input to the compressor.
(iii) Using your result from part (i), find the rate at which heat would be delivered to the kitchen air if the door were opened and the motor continued to run under the same conditions.