Extremal work of an endoreversible system with two finite thermal capacity reservoirs

Abstract

Extremal work of two finite thermal capacity reservoirs is determined. It is obtained by using optimal control theory. It is shown that the temperature of driving fluid changes exponentially with respect to flow velocity and process duration. The extremal work for heat engine mode is different from that for heat pump mode. The obtained results are compared with those obtained with infinite low temperature heat reservoir. The model and analysis in this paper provide a means for improved evaluation of the mechanical energy limits in practical systems. © 2009 Energy Institute.