A novel multi-reactor system for thermochemical heat storage through detailed modeling of K₂CO₃ particles

Thermochemical energy storage (TCES) is becoming increasingly important in the energy transition, as it can effectively bridge the gap between renewable energy supply and demand. In this study, the reaction kinetics of K₂CO₃ were characterized and validated. Based on this kinetic model, a numerical model of a packed bed of particles was developed using a coupled CFD-DEM approach. The results of the model were validated against experimental data of a particle bed, showing good agreement. The reaction rate of the system was found to be limited by the diffusion of water vapor into the material, which led to unsatisfactory performance on the bed scale due to significant temperature drop-offs. Although reducing particle size was found to be an effective way to improve system performance, practical concerns such as agglomeration and bed permeability limited its effectiveness. As an alternative, a multi-reactor system with adaptive flow rates was proposed, which improved system performance without the limitations of reducing particle size. The proposed modular system is capable of delivering 10 kW power at the temperature of 45 degrees for a duration of 19.5 h.