Performance in the Discharge Process of a Novel Zeolite-Water Adsorption Thermal Energy Storage System

In order to effectively recover low and medium grade heat energy, a novel combined cooling and heating storage system based on zeolite-water is proposed in this paper. The system coupled the zeolite-water adsorption process with the water evaporation refrigeration process during discharging process to realize generating cold energy and heat energy simultaneously. A more accurate kinetic model of zeolite and water adsorption is developed, and the thermodynamic performance of discharging process of the system is numerically analyzed. The results show the system has the higher energy conversion coefficient of 1.49 and the higher energy density of 1216.6 kJ/kg-zeolite. The change laws of system performances, such as energy generated, energy conversion coefficient and energy density, with key parameters during discharging process are revealed. The study provides a way for efficient utilization of low and medium grade heat energy.