Design and performance optimization of thermochemical energy storage reactor integrated high-thermal-conductivity porous structures

Thermochemical energy storage (TCES) systems are pivotal for mitigating the intermittency of renewable energy and recovering industrial waste heat. However, their medium-to-high-temperature application is hindered by sluggish reaction kinetics, inefficient heat/mass transfer, and structural instability under extreme conditions. This study addresses these challenges by proposing an optimized high-thermal-conductivity porous packed-bed reactor based on Co₃O₄/CoO redox system, aiming to enhance energy density, power scalability, and operational robustness. A validated multiphysics model coupling chemical kinetics, transient heat and mass transfer, and non-Darcy fluid dynamics was developed to analyze the interplay of critical parameters, including porosity, temperature, and pressure gradients. Key findings demonstrate that increasing the inlet temperatures to 1273 K boosts peak heat storage power by 33.59 W and reduces reaction time by 90 %, enabling effective operation under fluctuating solar inputs. Higher porosity (0.8–0.9) accelerates oxygen release, delivering peak thermal power outputs up to 61.95 W, whereas lower porosity (0.5–0.7) enhances thermal conduction but prolongs reaction duration. Elevated pressure gradients improve heat transfer but introduce additional mechanical stress. Additionally, a trade-off emerges in oxygen transport. Low porosity increases the central O₂ partial pressure by 25 %, which inhibits late-stage reactions due to gas retention. Notably, optimal thermal efficiency is achieved within 913–1233 K, striking a balance between rapid redox kinetics and controllable thermal power output. These insights provide actionable design principles and establish a scalable modeling framework to advance TCES technology for renewable energy integration and industrial waste heat recovery.