The high-temperature heat source for a cyclic heat engine is a steady-flow heat exchanger where R-134a enters at 80?C, saturated vapor, and exits at 80?C, saturated liquid, at a flow rate of 5 kg/s. Heat is rejected from the heat engine to a steady-flow heat exchanger, where air enters at 150 kPa and ambient temperature 20?C and exits at 125 kPa, 70?C. The rate of irreversibility for the overall process is 175 kW. Calculate the mass flow rate of the air and the thermal efficiency of the heat engine.
