Dual-objective topology optimization design for latent heat storage systems using composite phase change materials

Latent heat storage, as an efficient energy storage technology, holds great potential in the context of a low-carbon and clean energy supply framework. However, the auxiliary heat transfer enhancement techniques for latent heat storage materials still require further investigation. This study introduces a novel design approach for two-dimensional radial and axial topological optimization structures based on composite phase change materials, applied to horizontal latent heat storage devices. Initially, the types of nanoparticles and their volume fractions in the composite phase change material are determined. Subsequently, two-dimensional radial and axial topological structures are designed with optimization goals aimed at minimizing average temperature and thermal conductivity dissipation. These structures are incorporated into a three-dimensional phase change heat transfer model, which takes into account the effects of natural convection heat transfer. The results show that the fractal fins in the topological structures facilitate rapid heat exchange between the cold and hot fluids at the center and the composite phase change material. The analysis indicates that the radial topology optimized for minimizing average temperature significantly outperforms traditional annular fins, reducing the melting and solidification times of the composite phase change material by 48.24 % and 52.17 %, respectively, and improving the single heat cycle rate by 102.52 %. Finally, fractal dimension analysis confirms the biomimetic characteristics of the topological structures, revealing a high similarity to the natural fractal optimal solutions found in leaf veins and tree branches. This innovative combined optimization design provides valuable guidance for the optimization of efficient latent heat storage devices.