Question

A cylinder/piston contains saturated vapor R-22 at 10°C; the volume is 10 L. The R-22 is compressed to 2 MPa, 60°C in a reversible (internally) polytropic process. If all the heat transfer during the process is with the ambient at 10°C, calculate the net entropy change. 

Answer 1

 Notice:

n = 1.03, k = 1.17 n < k 

C.V. R-22 of constant mass m₂ = m₁ = m 

out to ambient. Energy Eq. m(u₂ − u₁) = ₁Q₂ − ₁W₂ 

Heat transfer from energy equation