A gas refrigerator operating on the reversed Brayton cycle using air is required to produce a cooling of 50 kW. Air enters the compressor at 275K and 1 bar. Air exits the compressor at 3.2 bar, passes through the condenser and enters the turbine at 310K. Both the turbine and compressor have 100% efficiency. Determine: 1. The temperature of air exiting the compressor. 2. Coefficient of performance. 3. The flow rate of air needed to operate the system 4. The entropy change of the air in the evaporator.