Design and optimization of large-scale thermochemical heat storage reactor and its application in integrated energy system

Thermochemical heat storage (THS), characterized by low-cost operation, high energy density, and minimal thermal losses, holds significant potential to mitigate renewable energy supply-demand imbalances and enable large-scale energy storage. This study investigates its integration into energy systems using multiscale modeling, coupling TRNSYS for system-level simulations with COMSOL Multiphysics for reactor-level analysis. Reactor simulations demonstrate that optimized gas inflow structures enhance heat storage/release rates, with flow rate reductions (attenuation ratio: 0.91–1.03) inducing <5 % outlet temperature variation at equivalent reaction conversions. High-precision models for medium-high temperature THS devices are developed via segmented function fitting of reaction rate and temperature-conversion curves (correlation coefficients >0.9996). Integrated system simulations reveal that the THS reactor substantially enhances energy storage capacity while improving operational efficiency. The technology achieves a 37.5 % increase in thermal energy output for hot steam supply systems, shifts energy consumption from peak/flat to off-peak periods, and reduces production costs by 24.0 %. Furthermore, systems integrating renewable energy devices with high-capacity storage demonstrate superior energy regulation, achieving 51.3 % lower electricity costs, a 30.6 % reduction in equivalent carbon emissions, and 88.6 % of grid power consumption shifted from off-peak to other periods. This study provides a theoretical foundation for industrial-scale THS deployment.