Consider an ideal gas refrigerator, using air, acting between 1 and 3 bar pressure. Assume that the temperature at the turbine entrance is 300 K and the temperature at the compressor entrance is 260 K.
a) Using a cold air-standard analysis with specific heat specified at 300 K, what is the thermal efficiency if the compressor and turbine are isentropic?
b) Repeat the above analysis, but with an isentropic efficiency of 80.4 percent at the turbine.