Volume 53

Numerical Analysis on Desorption Process of K2CO3 for Thermochemical Heat Storage Sitong Li, Zhuqing Li, Yu Chen, Hua Tian, Gequn Shu

Abstract

Energy storage technology can significantly enhance energy efficiency and conserve energy. Thermochemical adsorption heat storage based on salt hydrate is a crucial technology for long-term energy storage owing to its significant advantages of excellent energy storage density and minimal heat loss. K2CO3 is regarded as a prospective thermochemical heat storage material. In this work, a numerical model of the K2CO3 heat storage process is established using COMSOL based on the conservation of mass, momentum and energy, considering the variation of porosity with conversion degree and the flow of water vapor. Literature results confirm the validity of this model. The heat storage process is investigated, and the transient evolution of parameters such as temperature and concentration during the desorption process is described, elucidating the fundamental principles of the thermochemical heat storage process. The influence of various parameters on system performance is explored. The simulation results show that the porosity of the heat storage material shows obvious inhomogeneity in time and space. The porosity increases continuously with the progress of the reaction, which effectively promotes the progress of the reaction. Raising the heat flux and reducing heat loss can effectively decrease the reaction start-up time. This work offers insights into designing and optimizing thermochemical heat storage material and system.

Keywords Salt hydrate, K2CO3, thermochemical energy storage, numerical analysis, variable porosity