Design a reversed Brayton cycle closed-loop heat pump system. The isentropic efficiency of the turbine is 0.80 and the isentropic efficiency of the compressor is 0.78. The gas is to leave the...

Design a reversed Brayton cycle closed-loop heat pump system. The isentropic efficiency of the turbine is 0.80 and the isentropic efficiency of the compressor is 0.78. The gas is to leave the high-temperature heat exchanger at a temperature of 30°C after delivering 150 kW of heat to the warm space. The gas can exit the cold heat exchanger at a temperature no higher than 0°C. The mass flow rate of the gas can be no larger than 2 kg/s. Choose the gas to be used, and the pressures and temperatures entering and exiting the turbine and compressor. Determine the necessary mass flow rate and the coefficient of performance of the cycle as a heat pump. Justify your choices of design parameters.