Work

A High-Power, Flexible, and Magnetically Attachable Radiative Cooling Film

Year: 2024

Type: article

Abstract: Radiative cooling is an environmentally friendly passive cooling technology without energy consumption. Current research mainly focuses on optimizing the optical properties of radiative cooling films to improve their cooling performance. In practical applications, thermal contact between the radiative cooling film and the object plays a crucial role in determining the ultimate cooling performance. However, achieving optimal thermal contact has received limited attention. Here, we propose and experimentally demonstrate a high-power flexible and magnetically attachable and dettachable radiative cooling film consisting of polymer metasurface structures on a flexible magnetic layer. The monolithic film design can be conveniently attached to or detached from steel or iron surfaces enabling optimal thermal contact with minimal thermal resistance enabling uniform temperature distribution. Our magnetic radiative cooling film exhibits superior cooling performance compared to non-magnetic ones. It can reduce the temperature of stainless-steel plates under sunlight by 15.2 ℃, which is 3.6 ℃ more compared to that of non-magnetic radiative cooling film. The radiative cooling power can reach 259 W/m2 at a working temperature of 70 ℃. Unlike other commonly used attachment methods with thermal grease or one-off tape, our approach allows for detachment and reusability of the cooling film according to practical needs, enabling great simplicity, flexibility and cost-effectiviness, promising for broad applications, particularly for non-horizontal irregular surfaces, which were previously deemed challenging.

Source: Engineering

DOI: 10.1016/j.eng.2024.08.026