Numerical multiphysics simulation of a thermochemical energy storage device

This study presents a numerical investigation of a thermochemical energy storage device employing a CaCl2-expanded vermiculite composite as the active material. The simulation focuses on the discharging phase, during which cold and humid air flows through the system and water vapour is captured by the solid matrix, releasing thermal energy via an exothermic reaction. The model has been implemented in the COMSOL Multiphysics 6.1 software, which incorporates coupled physics for fluid flow, heat transfer in moist air, and water vapor transport in porous media. The sorption process is represented by a heat source term that is dependent on the local vapour concentration. The obtained results demonstrate a peak outlet temperature of 34.7°C for an inlet of 24°C, along with a significant decrease in vapour concentration through the bed, thereby confirming effective heat release and moisture uptake. Spatial maps have been utilised to illustrate the progression of the hydration front. The simulation provides a detailed view of the thermal and sorption dynamics during discharge and opens up interesting perspectives for future experimental validation and system optimisation.