Entransy analysis of irreversible Carnot-like heat engine and refrigeration cycles and the relationships among various thermodynamic parameters

Abstract

Because of the energy needs of the world and the issues involved with global warming, analyzing andoptimizing power cycles have increased in importance. In this paper, the concepts of entransy dissipation,entropy generation, power output, exergy output, energy, exergy efficiencies for irreversible heat enginecycles and entransy dissipation, entropy generation, power inputs, exergy input, entropy generation, COPand the exergy of efficiency for the irreversible refrigeration cycle are applied as a means of analyzingthem. The results are obtained numerically, and the optimum or critical values are determined for adimensionless temperature ratio and a dimensionless heat conductance ratio. Finally, recommendationson the design and range of operating conditions for the cycles are presented. Values ofTC/TE(x), can beselected between 0.5 and 0.55 and values ofkE/kC(y) in the range of 0.3–0.5 can be selected for high per-formance and low losses in a heat engine. Choosing values ofTC/TE(x) andkC/kE(y) as low as possible forhigh performance, besides low thermodynamic losses (entropy generation and entransy dissipation) forthe refrigeration cycle.