Performance Analysis of a Thermochemical Energy Storage Reactor Based on SrBr2·6H2O

To improve the efficiency of thermochemical energy storage (TCES) systems, this study developed a three-dimensional multi-physics field coupling model for a closed SrBr₂·6H₂O reactor. The model integrates reaction kinetics with the conservation equations of mass, momentum, and energy to analyze the effects of fin structure and material porosity on energy charge/discharge performance. The results indicate that increasing fin number enhances heat transfer. When the fin number rises from 4 to 8, the thermochemical material (TCM) temperature during charging increases, shortening the charging time by 18.85% and boosting the charging power. During discharging, the TCM temperature drops, cutting the discharging time by 8.02% and increasing the discharging power. Fin thickness affects reactor performance in a similar yet weaker way. As the thickness increases from 1 mm to 3 mm, the charging time shortens by 10.47% and the charging power increases, while the discharging time decreases by only 4.22% with a slight power increase. Properly notched serrated fins can enhance reactor performance; compared with conventional longitudinal fins, serrated fins with 90% and 80% volume result in only a slight increase in energy charge/discharge time. However, excessive notching weakens the heat transfer enhancement effect. Increasing TCM porosity from 0.30 to 0.75 reduces the charging and discharging times by 32.98% and 18.84%, respectively, but significantly decreases the charge/discharge power. This study provides valuable references for the design and optimization of compact thermochemical energy storage devices.