Optimized Dissipative Heat Engine With Finite-Sized Heat Reservoirs

Abstract

Dissipative heat engine with finite-sized heat reservoirs in which the maximum efficiency is set to be and the minimum efficiency (the efficiency at maximum power) is set to be is optimized under considerations of dissipations. The study analytically investigated the dissipative heat engine with finite-sized heat reservoirs under the finite-time two isothermal processes. During the isothermal expansion, the working substance is thermalized with a hot reservoir to absorb heat and then attached to a cold reservoir during which it release some amount of heat. By employing a unified criterion for energy converters, the objective function (the difference of effective useful energy and lost useful energy) is subjected to optimization with respect to period. From the optimized period, quantities of importance: power and efficiency were found. These quantities were scaled with their values at the maximum power. Efficiency-wise the optimized efficiency is better than its value at maximum power; however, power-wise the maximum power is greater than the optimized power. The figure of merit which shows the overall performance of the heat engine is evaluated by taking the product of scaled power and scaled efficiency. It has a mixed advantage and disadvantages.