An air-standard cycle with variable coefficients is executed in a closed system and is composed of the

Question:

An air-standard cycle with variable coefficients is executed in a closed system and is composed of the following four processes:
1-2 v = constant heat addition from 100 kPa and 27°C to 300 kPa
2-3 P = constant heat addition to 1027°C
3-4 Isentropic expansion to 100 kPa
4-1 P = constant heat rejection to initial state
(a) Show the cycle on P-v and T-s diagrams.
(b) Calculate the net work output per unit mass.
(c) Determine the thermal efficiency.