For humans, staying cool in the summer heat often means expending energy on air conditioners, fans, and other cooling devices. But scientists are exploring other, less energy-intense options for beating the heat. At a conference, researchers recently unveiled a plant-based bi-layer film that’s able to stay about 7 degrees Fahrenheit cooler than its surroundings while illuminated by the sun.
The film uses passive daytime radiative cooling, which means that it emits its heat into space (without getting absorbed by the air nearby) without any external power source. A square meter of the film generates over 120 watts of cooling power, comparable to many residential air conditioners. Even better, the films are built from layered cellulose, a sustainable and renewable resource, and can be made in a variety of colors.
The team hopes to transition their films to commercial manufacturing, where they can be incorporated into buildings and automobiles to provide some passive cooling, thereby limiting reliance on air conditioners. (Image and research credit: Q. Shen et al.; via Ars Technica)