Influence of heat interaction modelling on the efficiency of endoreversible closed regenerative solar Brayton cycles

Abstract

In endoreversible cycles, irreversibility is considered only between the systems and their surroundings. In this paper, the modelling of heat interaction with a solar regenerative Brayton cycle is studied with regard to various fidelities based on the first and second laws of thermodynamics. The effect of linearity and nonlinearity related to both convective and radiative heat interactions with the hot and cold reservoirs as well as radiation losses of the solar Brayton cycle have been studied, which is complementary to similar attempts for Carnot cycle. Total efficiencies are compared between various implemented models. The effect of temperature of six critical sections of the whole engine on the collector efficiency, cycle thermal efficiency and the system total efficiency has been studied. Besides, a comparison is done for a real example to show the importance of considering the nonlinearities for calculating thermal efficiency of a closed-loop Brayton cycle at different hot source temperatures, as well. These would help a more efficient analysis of the emerging power cycles that can accelerate progress toward low-carbon power production.