A system consists of 2 kg of CO2 gas initially at state 1 where P1 = 1 bar and T1 = 300 K. The system undergoes a power cycle consisting of the following processes:
Process 1-2: constant volume to P2 = 4 bars
Process 2-3: expansion with P*v^1.28 = constant
Process 3-1: constant pressure compression
Assuming ideal gas behavior, show the process on a P-v diagram and calculate the thermal efficiency of the cycle, where thermal efficiency is defined as the net work out divided by the heat in.