Question

A compressor receives R-134a at –10°C, 200 kPa with an exit of 1200 kPa, 50°C. What can you say about the process?

Answer 1

Properties for R-134a are f

Inlet state: si = 1.7328 kJ/kg K

Exit state: se = 1.7237 kJ/kg K

Steady state single flow:

Since * decreases slightly and the generation term can only be positive, it must be that the heat transfer is negative (out) so the integral gives a contribution that is smaller than -sgen.