Optimal configuration of a class of irreversible heat engines. I

We determine the optimal configuration for a class of heat engines with finite cycling times. The engines studied are those for which irreversible process occur through the coupling of the engine to the environment, while the working fluid in the engine is assumed to undergo reversible transformations. For the case in which the only irreversible process is heat conduction, we derive the optimal configuration of these engines for two different operating goals: maximum average power output and maximum efficiency. We suggest figures of merit based on these optimal configurations which may be more useful than those based on reversible processes.