Optimization and performance analysis of directional heat injection in thermally activated energy-storage composite walls

To address the capacity mismatch between heat injection and thermal diffusion in thermally activated walls, this study proposes an enhanced thermally activated wall (ETAW) design to improve energy-storage efficiency and energy-saving potential. A dynamic heat transfer model is developed to compare the thermal performance of ETAW with that of conventional thermally activated walls (CTAW) and conventional energy-saving walls (CW). Local sensitivity analysis is conducted to investigate the economic impacts of fin parameters, climate conditions, and insulation thickness. Results demonstrate that ETAW exhibits significantly superior dynamic thermal performance relative to CTAW and CW, although the degree of improvement depends on the heat injection mode. Increases in trunk fin size and branch fin size both effectively reduce total operating energy consumption and costs, with the branch fin size exhibiting a more pronounced influence. Adopting a smaller branch-fin inclination angle (e. g. 60°) and a left-oriented installation can reduce operating costs and energy consumption by approximately 10.9% and 10.7% respectively. Insulation thickness shows strong correlations with energy efficiency and economic performance; recommended reduction rates should not exceed 40% in severe cold zones and may be extended to up to 60% in hot-summer zones.