Numerical study on enhanced radiation cooling characteristics of Ti-GE-W microstructure surfaces

•A metamaterial model based on Ti-Ge-W materials was proposed for radiation cooling.•Adding metal strips horizontally could meet better results.•The structure had a perfect emissivity in the atmospheric window range. Surfaces with high infrared emission characteristics in the atmosphere window range (8–13 μm) play a pivotal role in radiation cooling. In this paper, a Ti-Ge-W based metamaterial was proposed as a cooling surface and the influence of its geometric parameters on the emissivity was analyzed as well. Studies of the physical mechanism showed that: The spectral emissivity of the single structure can reach over 80% in the range of 9–13 μm. In contrast, the expansion of more Ti strips in the horizontal direction can effectively broaden the emission spectrum and enhance the radiation performance. Due to the coupling effect between the surface plasmon polaritons (SPPs) and magnetic polarizations (MPs), the structures showed strong absorption properties, leading to strong emissivity according to Kirchhoff's Law. This research provides a new idea in radiation cooling, which is of great value in building cooling, aerospace refrigeration, and other fields.