Question

A piston-cylinder assembly undergoes a cycle consisting of the following three processes:

 • Process 1-2: Compression with constant internal energy

 • Process 2-3: Constant-volume cooling to p3 = 100 kPa, V3 = 0.1 m³

 • Process 3-1: Constant-pressure expansion with W₃₁ = 12 kJ

 Sketch the cycle on a p-V diagram, labeling each of the states and indicating the process directions with arrows. If the work for the entire cycle is W_cycle = -20 kJ and changes in kinetic and potential energy are negligible, determine:

 a) The volume at state 1 [0.2 m³]

 b) The work and heat transfer for process 1-2 [30 kJ, 30 kJ]

 c) Is this cycle a power cycle or a refrigeration cycle? Explain.

Answer 1

(c) Since the net work is negative. It is a refrigeration cycle.