A thermodynamic study and numerical analysis of Ericsson, Brayton, and Carnot cycles for the thermally regenerative electrochemical refrigerator

Abstract

Non-vapor-strand refrigeration, the zero-global-warming-potential cooling technologies, has garnered attraction in response to the ever-increasingly severe environmental issues. The thermally regenerative electrochemical refrigerator (TRER) is one of the promising candidates because of its superior performance theoretically. However, few thermodynamic cycles associated with electrochemical reactions have been developed to analyze this emerging work-to-heat technology. This study intends to fill this gap by investigating three typical thermodynamic cycles, i.e., Ericsson, Brayton, and Carnot cycles, based on the characteristics of thermodynamics and electrochemistry. The corresponding analytic models are derived and the core parameters are studied. The results reveal that the temperature coefficient has a huge and different impact on different cycles, that is, positive, negative, and negligible correlations to the coefficient of performance (COP) of the Carnot, Brayton, and Ericsson cycles, respectively. The specific heat capacity of the TRER would degrade the COP in Ericsson and Carnot cycles, while the curve of Brayton cycle shows a convex trend. The electrochemical refrigeration will not be workable if the internal resistance is more than a certain value. Furthermore, the performance of CECR can be improved by shortening the duration of its isentropic forward electrochemical phase. This study will provide useful insights into the selection and optimization of various thermodynamic cycles for TRER.