Propane is to be compressed from 0.4 MPa and 360 K to 4 MPa using a two-stage compressor. An interstage cooler returns the temperature of the propane to 360 K before it enters the second compressor. The intermediate pressure is 1.2 MPa. Both adiabatic compressors have a compressor efficiency of 80%.

(a) What is the work required in the first compressor per kg of propane?

(b) What is the temperature at the exit of the first compressor?

(c) What is the cooling requirement in the interstage cooler per kg of propane?