Integrated heat and cold storage enabled by high-energy-density sorption thermal battery based on zeolite/MgCl2 composite sorbent

Abstract

Thermal energy storage (TES) plays a critical role in renewable energy utilization, waste heat recovery, and heating/cooling applications. However, low energy density is a long-standing challenge for conventional TES systems based on sensible heat and latent heat methods, and thus impedes the widespread deployment of heat storage and cold storage. Herein, a novel high-power/energy-density sorption thermal battery (STB) is developed for realizing integrated heat and cold storage by using zeolite 13X-based composite sorbent-water working pair. The zeolite 13X is firstly treated with MgCl2 salt to improve water uptake and regulate sorption equilibrium characteristics. The results demonstrate that the energy density of zeolite 13X/MgCl2 can be improved by 15.1% when compared to zeolite 13X. The STB exhibits the distinct capability of realizing high-power/energy-density heat storage and cold storage, and the working temperature can be changed according to different demands. The average power densities for heat storage and cold storage are 279.66 W/kg and 242.95 W/kg, respectively. Meanwhile, the average energy densities for heat storage and cold storage are as high as 686.86 kJ/kg and 597.13 kJ/kg, respectively, superior to the current sensible/latent heat energy storage. The proposed zeolite/MgCl2-based sorption thermal battery offers a promising route to realize high-density heat storage and cold storage simultaneously based one thermal energy storage device.