The dependence of power cycles' performance on their location relative to the andrews curve

Abstract

The adoption of the closed cycle and of working fluids other than steam or air gives the possibility of utilizing for power cycles regions of the temperature-entropy diagram which are inaccessible when the working media are water or combustion products and which enjoy some useful peculiarities. A number of fluids are presented which are suitable for industrial applications and which allow the organization of power cycles covering the liquid, gaseous, and hypercritical regions of the state diagram of a typical substance. Efficiency, specific work, heat transfer surfaces, dimensions of turbomachines, distribution of losses among the various components relating to different fluids and cycles are analyzed and reported. The results strongly support the conclusion that the nature of the working fluid is a powerful tool to adapt the characteristics of power cycles to the widely differing requirements encountered in technical applications.