A vapor-compression refrigeration system for a household refrigerator has a refrigerating capacity of 1500 Btu/h and uses R-12 as the refrigerant. The refrigerant enters the evaporator at 21.422 lbf/in2 and exits at 5oF. The isentropic compressor efficiency is 70%. The refrigerant condenses at 122.95 lbf/in2 and exits the condenser as subcooled at 90oF. There are no significant pressure drops in the flows through the evaporator and condenser. Determine
(a) The mass flow rate of refrigerant in lb/min,
(b) The compressor power input in horsepower and
(c) The coefficient of performance.