Daytime radiative cooling of single-board computer in nearly enclosed unmanned surface vehicle

The dramatic boost in work efficiency of computers has led to miniaturized electronics being used in harsh outdoor environments. For example, single-board computers (SBCs) are expected to function stably in near-enclosed surroundings. The traditional heat dissipation strategies of thermal conduction and convection cannot remove heat from an enclosure. In this study, we employ the concept of daytime radiative cooling (DRC) for effective thermal management of the central processing unit (CPU) of SBCs. Metaparticles composed of multiple ceramic materials display high broadband emissivity (>0.95) in mid-wavelength infrared (MWIR) to long-wavelength infrared (LWIR) ranges, as well as solar reflectance of greater than 0.97. When the SBCs were operated in a sealed space, the metaparticles lowered the temperature of the CPU by more than 10 °C under intense solar irradiance (ca. 1000 W/m²) and by 5–7 °C during the night. Compared with SBCs operated without DRC strategies, the metaparticles led to a 60–70 % improvement in the performance of the image frame rates of the visual identity system of an enclosed SBC integrated into an unmanned surface vehicle (USV) under sunny weather. Thus, by passively cooling the CPU, the metaparticles significantly improved the efficiency of SBCs and maintained the reliability of USVs.