Question

Calculate the reversible work and irreversibility for the process , cylinder with a piston restrained by a linear spring contains 2 kg of carbon dioxide at 500 kPa, 400°C. It is cooled to 40°C, at which point the pressure is 300 kPa.  assuming that the heat transfer is with the surroundings at 20°C.

Answer 1

Linear spring gives 

= 293.15 x 2[ 0.99 ln(313/673) - 0.1889 ln(300/500)] - 45.72 + 623.9 = -387.8 - 45.72 + 623.9 = 190.4 kJ