Texts: A gas cooling cycle with a pressure ratio of 3 uses helium as a working fluid. The temperature of helium is -10 °C at the compressor inlet and 50 °C at the turbine inlet. Assuming isentropic efficiencies of 80 percent for both the turbine and the compressor, determine a) the minimum temperature in the cycle, b) the coefficient of performance, and c) the mass flow of helium for a cooling load of 18 kW.