Carnot-like Heat Engine Research Articles

Optimal operation of finite-time tricycles with heat conduction losses

We consider the issue of in-principle limits to the finite-time operation of a cycling working fluid acting as an agent in the transfer of heat among three heat reservoirs. The set of feasible operations of such a heat engine is explicitly described and its boundary is characterized as the set of operations which allocate time optimally among the heat conduction branches for a wide variety of cost functions. One point on this boundary represents the operation that maximizes the heat output at the high-temperature heat reservoir. There is a natural notion of efficiency for such an operation and the result in this case generalizes the well known result of Curzon and Ahlborn for the efficiency of a Carnot-like heat engine at maximum power.

The theoretical efficiency limits for a combined cycle under the condition of maximum power output

Using the theory of finite-time thermodynamics, an optimal performance analysis of an internally and externally irreversible Carnot-like single heat engine was studied to determine the maximum power and the efficiency at the maximum power output. Based on this study, the maximum power and the efficiency at the maximum power output of an irreversible combined heat engine (two single irreversible heat engines in a cascade) were obtained for steady state operation. The optimal performance of the combined cycle was expressed in terms of two design parameters. The effects of these parameters on the performance of the combined cycle were examined. The upper and lower bounds to the maximum power and the efficiency at the maximum power were determined. These results were compared with those obtained for a single cycle. It was shown that it is possible to design a combined engine which generates more power and is more efficient than a single cycle.