A two-stage compressor is used to compress air from 100 kPa at 298 K to 900 kPa at a rate of 0.5 kg/s. After the first stage compressor, an intercooler isobaric ally cools the air to 350 K before entering the second compressor stage. The pressure ratios across each compressor stage are equal and each compressor is adiabatic with an isentropic efficiency of 86%. An accurate value for the power required to drive the two-stage compressor is required, therefore solve the problem using the variable specific heats assumption.
i) Draw an equipment diagram, labelling all heat transfer and work interactions.
ii) Determine the pressure after the first stage compressor in kPa.
iii) Show the process on a P-v (pressure-specific volume) diagram labelling all significant points in the process and the direction of the process.
iv) Determine the heat transfer from the intercooler in kW.
v) Determine the total power required to drive the two-stage compressor in kW.