The efficiency of the Carnot cycle with arbitrary gas equations of state

The derivation of the efficiency of the Carnot cycle is usually done by calculating the heats involved in two isothermal processes and making use of the associated adiabatic relation for a given working substance's equation of state, usually the ideal gas. We present a derivation of the Carnot efficiency using the same procedure with the Redlich–Kwong gas as a working substance to solve calculation difficulties raised by Agrawal and Menon ( 1990 Eur. J. Phys. 11 88–90 ). We also show that using the same procedure, the Carnot efficiency may be derived regardless of the functional form of the gas equation of state.