A vapor-compression refrigeration system, with a capacity of 15 tons, has superheated Refrigerant R-134a vapor entering the compressor at 15oC, 4 bar and exiting at 12 bar. The compression process can be taken as polytrophic, with n = 1.01. At the condenser exit, the pressure is 11.6 bar and the temperature is 44oC. The condenser is water-cooled, with water entering at 20oC and leaving at 30oC with a negligible change in pressure. Heat transfer from the outside of the condenser can be neglected. Determine
(a) The compressor power input in kW,
(b) The coefficient of performance (COPR) and