1. Refrigerant 134a as saturated vapor at 210°C enters a compressor operating at steady state with a mass flow rate of 0.3 kg/s. At the compressor exit the pressure of the refrigerant is 5 bar. Stray heat transfer and the effects of motion and gravity can be ignored. If the rate of exergy destruction within the compressor must be kept less than 2.4 kW, determine the allowed ranges for (a) the power required by the compressor, in kW, and (b) the exergetic compressor efficiency. Let T0 5 298 K, p0 5 1 bar.
2. For the turbine-compressor arrangement of Problem 6.164, determine the exergetic efficiency for (a) the turbine, (b) the compressor, (c) an overall control volume enclosing the turbine and compressor. Let T0 5 300 K.