Modeling of reactor bed of a thermochemical energy storage system

Purpose This study aims to develop a numerical model to simulate the thermochemical energy storage (TCES) process within a porous reactor bed containing potassium carbonate (K2CO3) salt hydrate, focusing on the impact of thermal diffusion and vapor transport length scales on reactant conversion for a prescribed reaction time scale. Design/methodology/approach Using a finite volume-based numerical technique to solve coupled nonlinear equations governing reaction kinetics, heat transfer and vapor transport, the model identifies critical thermal and vapor transport length scales that influence reactor performance during discharging (hydration) process. Findings The results confirm that beyond certain length scales, thermal and vapor transport rates limit reaction rates. Specifically, during the discharging process with a hydration time scale of 1500 s, the critical thermal diffusion (Xcr) and vapor penetration (Ycr) length scales were approximately 10 mm and 45 mm, respectively, for an inlet vapor pressure of 1500 Pa and a side wall temperature of 30°C. Increased inlet vapor pressure significantly extended the critical vapor penetration length scale, aligning with findings in recent literature. Practical implications These insights highlight key design parameters essential for optimizing reactor efficiency and scalability in practical applications of TCES systems. Originality/value The present paper highlights the impact of thermal diffusion and vapor transport length scales on reactant conversion within the reactor bed module for a prescribed reaction time scale.