Performance Analysis of Composite Sorbents in Thermal Energy Storage System

Composite adsorbents, prepared by impregnating hygroscopic salt into silica gel pores are considered as promising storage materials in space heating for their high specific storage density and low regenerating temperature. In this paper, a numerical model of the adsorber heat exchanger was developed. Four kinds of composite adsorbents were tested under different conditions. The experiments were conducted to investigate the effect of their nature, the regenerating temperature, the air flow rate and number of transfer unit on the thermal storage performances. The results reveal that thermal storage performances increases significantly with CaCl₂ concentration ranged from 10% to 40%. COP declines with the regenerating temperature and air flow rate, ranged from 80°C to 90°C and 4 m³/min to 6 m³/min respectively, while NTU is another case. The optimization of thermal performance of TES can be achieved by compromising between the above factors.