Bioinspired all-day adaptive radiative cooler with high-power cooling and efficient suppressing overcooling

This research presents a design in the bionic on-off switch layer and thermal insulation layer, crucial for the cooling power adjustment of the radiative cooler. The design features a change in the upper surface area of the on-off switch layer, inspired by the unfolding and folding behaviors of pinto peanut leaves in day and night, which enables high-power cooling during the day and suppresses overcooling at night. The introduction of a bulge-pit structure in the thermal insulation layer reduces the heat exchange between the cooler and the outside. The novelty of this research lies in the integration of a bionic design, an innovative bulge-pit structure, and an optimized polyacrylonitrile spinning layer on the surface of green balsa wood. The study examines the cooling properties of the cooler under simulated day and night conditions. Key findings reveal that day subambient radiative cooling of 6.6( degrees )C, which is slightly better than a passive radiative cooler. At night, it elevates the ambient temperature by 3.4 C-degrees compared to a passive radiative cooler. The total energy savings applied in a specified area for all day are estimated to reach up to 770 kJ. This design marks a significant advancement in the radiative cooling field.