A vapor-compression refrigeration system for a household refrigerator has a refrigerating capacity of 1000 Btu/h. Refrigerant enters the evaporator at 2108F and exits at 08F. The isentropic compressor efficiency is 80%. The refrigerant condenses at 958F and exits the condenser subcooled at 908F. There are no significant pressure drops in the flows through the evaporator and condenser. Determine the evaporator and condenser pressures, each in lbf/in.2, the mass flow rate of refrigerant, in lb/min, the compressor power input, in horsepower, and the coefficient of performance for (a) Refrigerant 134a and (b) propane as the working fluid.