Finite time thermodynamic optimization for performance of absorption energy storage systems

Abstract

Absorption energy storage (AES) has attracted worldwide attention due to the high energy storage density and environmental friendliness. To optimize the performance of the AES system, a finite time thermodynamic (FTT) model considering some influencing factors such as time, heat transfer area, heat transfer temperature difference, internal friction and dissipation has been developed in this paper. A new concept of ratio of charging and discharging time is proposed. The general relation of the energy storage efficiency, energy storage rate and energy release rate are induced based on FTT analysis. The distribution of the total thermal conductivity was optimized under the condition of a certain total thermal conductivity and the optimized maximum cooldown release rate has been increased by 14%. The optimal operating conditions of the AES system are obtained. Furthermore, the influences of the internal irreversibility, ratio of charging and discharging time and heat source temperatures on the performance of the AES system are analyzed. The research results can provide theoretical basis and guidance for the AES system design and optimization.