Optimización con el criterio de mínima generación de entropía de un ciclo Brayton no endorreversible con recuperación externa

Abstract

In order to be able to design better and more efficient systems, this article contributes to the development of the Brayton cycle including multiple internal and external irreversibilities, with external energy recovery using finite-time thermodynamics and especially optimizing the performance with the criterion of minimal entropy generated. The model proposed counts on the innovation of two heat exchangers external to the cycle, that act as energy recovery devices, one in the line of high HRX, which recovers the energy that was not well-spent by the fluid used in the exchanger HHE or source; and the other one in the line of low LRX, recovering the energy the fluid loses in the draining well or CHE exchanger. This energy recovered is properly used by an incompressible fluid, that, for this article, it has been taken as water and is it considered as flow in the process. Irreversibilities such as pressure drops within piping and heat exchangers, finite differences of temperature and finite conductance of heat transfer (U ⋅ A) have been taken into account in the cycle analysis, which contributes to the knowledge in this field. The variables of the system susceptible for optimizing were: compressor pressures relation, thermal capacitance of fluid used and the low-temperature fluid, ratio of specific heats of the fluid used, the distribution of total thermal conductance of the exchangers belonging to the cycle, such as the exchangers that work as recovery system. The numerical part was processed using the TOOLBOX of optimization of the program MATLAB