Biomimetic hierarchical structure for enhancing concentrated solar energy converting and utilizing efficiency

Concentrated solar technology has the problems of local overheating, inadequate light absorption, and insufficient diffusion of solar irradiation energy flow. In this study, the idea of using biomimetic hierarchical structure is proposed to solve these problems through radiation regulating and photon managing, thereby enhancing the conversion and utilization efficiency of concentrated solar energy. The performance of uniform porous structure and biomimetic hierarchical structure are comparatively investigated. The geometrical parameters (diameters, ratio, and filling factor) of the biomimetic hierarchical structure are investigated and optimized by finite-difference time-domain (FDTD) method combined with particle swarm optimization algorithm. The results indicate that the biomimetic hierarchical structure can enhance the effective light absorption and energy flow diffusion efficiency of concentrated solar energy, an increasing pore size is better for the biomimetic hierarchical structure than a decreasing pore size, and the feature sizes which serve as the boundary between large and small pores are found. For the effective light absorption, the biomimetic hierarchical structure has an enhancement of 3.4%, and for the energy flow diffusion efficiency, this structure has an enhancement of over 25%, compared with the uniform porous structure. This research can provide general and valuable guidance for enhancing solar energy utilizing efficiency of high-temperature solar thermochemical reactors, solar cells, and photocatalytic carriers, based on the biomimetic hierarchical structure.