Maximum Power Point Characteristics of Generalized Heat Engines with Finite Time and Finite Heat Capacities

Abstract EN

We revisit the problem of optimal power extraction in four-step cycles (two adiabatic and two heat-transfer branches) when the finite-rate heat transfer obeys a linear law and the heat reservoirs have finite heat capacities.

The heat-transfer branch follows a polytropic process in which the heat capacity of the working fluid stays constant.

For the case of ideal gas as working fluid and a given switching time, it is shown that maximum work is obtained at Curzon-Ahlborn efficiency.

Our expressions clearly show the dependence on the relative magnitudes of heat capacities of the fluid and the reservoirs.

Many previous formulae, including infinite reservoirs, infinite-time cycles, and Carnot-like and non-Carnot-like cycles, are recovered as special cases of our model.