Design of radiative cooling covers for automobiles with maximized cooling power

Due to the capability of cooling objects without energy consumption by emitting thermal radiation into outer space, radiative cooling technologies have found broad applications in different scenarios. Despite the high demand for cooling automobiles under sunlight, there is no specialized design of a radiative cooling cover for automobiles. This paper demonstrates the first specialized radiative cooling cover for automobiles. As the overall cooling power is linearly proportional to the surface area, we designed a conch-shaped foldable radiative cooling film car cover to maximize the surface area within a limited space, resulting in a total cooling power of 5,726.8 W. As a result, the maximum temperature drop can reach 27 °C under strong solar irradiance (800 Wm−2). In addition, we further demonstrate the effects of the surface coverage on the cooling performance by measuring the temperature drop at different surface coverages (100 %, 90 %, 40 %, and 10 %). It is found that the radiative cooling cover can effectively cool the inner temperature of a car even with a small surface coverage. In addition, it confirms that enlarging surface area is an effective way to improve cooling performance. Our results open new possibilities in designing radiative cooling covers that can achieve large cooling power within a limited footprint. The design principle can be extended and generally applied to other radiative cooling devices for various applications.