An air standard cycle is executed in a closed system and is composed of the following four processes: (1) 1-2: v = constant during heat addition from 15 psia and 85oF in the amount of 320 Btu/lbm, (2) 2-3: p = constant during heat addition to 3500oR, (3) 3-4: Isentropic expansion to 15 psia, (4) 4-1: p = constant during heat rejection to initial state.
(a) Calculate the amount of heat addition in the cycle and
(b) Determine the thermal efficiency (ηth). Use the IG model.