Performance of sorption thermal energy storage in zeolite bed reactors: Analytical solution and experiment

Sorption thermal energy storage (STES) has the advantage of high energy storage density and low heat loss, which has been considered as one of the promising solutions to achieve carbon neutrality in buildings. An insight into the thermal energy storage performance of reactors enables the optimization of STES systems. In addition, the analytical solution is concise and understandable in physical significance. In the present work, the perturbation theory was introduced to derive the analytical solutions for the fluid and solid temperatures in the reactor during the discharging process. Subsequently, a zeolite 13X STES system was built to conduct charging and discharging experiments. Based on the derived analytical solution, the fluid temperature at different axial positions in the reactor and energy storage density (ED) of zeolite were calculated and compared with the measured data. The results showed that there was a good agreement between the experimental test and the analytical solution, in which the maximum deviation of the energy storage density was less than 4 %. The analytical solution could obtain specific functional expressions for STES performance parameter of ED and further receive the results quickly.