Investigation of a three-phase thermochemical reactor through an experimentally validated numerical modelling

Highlights: • The paper presents a numerical model for a three-phase thermochemical reactor. • Model validation is conducted with experimental results. • Key parameters are analysed with the validated numerical model. -- Abstract: For some renewable energy such as solar energy, the mismatch between the side of generation and demand should be tackled by thermal energy storage techniques with high energy density and low thermal losses. Thermochemical energy storage is a promising technology to meet these requirements. Within a thermochemical energy storage system, reactor is one of the critical components to achieve the optimal performance. While few studies have investigated the three-phase reactor applied in open thermochemical system in building's application. This study presents a numerical description of a three-phase thermochemical reactor with air, solid thermochemical material and water flow. Zeolite 13X has been selected as the working thermochemical material and experimental tests have been conducted to obtain the temperature profiles in both the charging and discharging processes. A two dimensional numerical model of the reactors has been developed, verified and validated. A good agreement has been obtained by comparing the numerical and experimental results with the root mean square percent error ranging from 6.02% to 12.29%. Additionally, parameters sensitivity analysis has been conducted for reference diffusivity, heterogeneity factor, and initial water uptake of the zeolite. The numerical model and the investigation provide the tool for reactor design optimisation, charging and discharging processes evaluation and reactor performance improvement.