A three-material chimney-like absorber with a sharp cutoff for high-temperature solar energy harvesting

For high-temperature solar absorbers, the inconspicuous cutoff in absorptivity gives rise to substantial selfradiation loss, reducing the heat transfer efficiency of solar energy conversion systems. To further improve thermal efficiency, we designed a broadband (300-1500 nm) absorber with a sharp cutoff based on chimney-like metamaterials. The design involves three different materials, each with unique optical properties, which work together to achieve the desired absorption spectrum. The proposed absorber provides a high absorptivity over 0.95 at 340-1400 nm with a narrow cutoff bandwidth of less than 300 nm. Additionally, this design can maintain good absorption performance over a wide angular range and at high temperatures. Based on theoretical calculations, the proposed absorber achieves an excellent thermal efficiency of 91.62% under 1200 K and 1000 solar concentrations, which is better suited for high-temperature solar energy harvesting.

Automated summary

This study proposes a highly efficient solar absorber with a broad absorption spectrum, significantly improving the thermal conversion efficiency.