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

Question:

An air-standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes:
1-2 v = constant heat addition from 14.7 psia and
80°F in the amount of 300 Btu/lbm
2-3 P = constant heat addition to 3200 R
3-4 Isentropic expansion to 14.7 psia
4-1 P = constant heat rejection to initial state
(a) Show the cycle on P-v and T-s diagrams.
(b) Calculate the total heat input per unit mass.
(c) Determine the thermal efficiency.