Consider the heat engine described in Problem 74.
Consider a heat engine that is not reversible. The engine uses 1.000 mol of a diatomic ideal gas. In the first step (A) there is a constant temperature expansion while in contact with a warm reservoir at 373 K from P1 = 1.55 × 105 Pa and V1 = 2.00 × 10−2 m3 to P2 = 1.24 × 105 Pa and V2 = 2.50 × 10−2 m3 . Then (B) a heat reservoir at the cooler temperature of 273 K is used to cool the gas at constant volume to 273 K from P2 to P3 = 0.91 × 105 Pa. This is followed by (C) a constant temperature compression while still in contact with the cold reservoir at 273 K from P3 , V2 to P4 = 1.01 × 105 Pa, V1 . The final step (D) is heating the gas at constant volume from 273 K to 373 K by being in contact with the warm reservoir again, to return from P4, V1 to P1, V1.
(a) For each step in the cycle, find the work done by the gas, the heat flow into or out of the gas, and the change in internal energy of the gas.
(b) Find the efficiency of this engine.
(c) Compare to the efficiency of a reversible engine that uses the same two reservoirs.