A vapor-compression refrigeration system operates at steady state with propane as the working fluid and has a capacity of 5 tons. Saturated vapor at 0oF enters the compressor and exits as superheated vapor at 120 oF and 180 lbf/in2. Heat transfer from the compressor to its surroundings occurs at a rate of 3.5 Btu per lb of refrigerant passing through the compressor. Liquid refrigerant enters the expansion valve at 85 oF and 180 lbf/in2. The condenser is water-cooled with water entering at 65oF and leaving at 80 oF with a negligible change in pressure. Determine: (a) the compressor power input, in horsepower, (b) the mass flow rate of cooling water through the condenser, (c) the coefficient of performance, and (d) the coefficient of performance if the system is operated as a heat pump.