Hybrid rooftop device to harvest solar energy and passively cool buildings at the same time

Air conditioners are major energy hogs, and with global temperatures on the rise the problem is only set to get worse. When we first looked at the radiative cooling system being developed by Fan and his associates in 2013, it was suggested the passive rooftop panels could be used in place of solar panels used to generate electricity to run AC systems, or to cool buildings in off-grid areas. But now the team has found an even better solution, in a dual-purpose device that means passive cooling doesn’t have to mean sacrificing electricity generation for rooftop real estate.

“We’ve built the first device that one day could make energy and save energy, in the same place and at the same time, by controlling two very different properties of light,” says Fan.

The hybrid device takes the form of a double-layered solar panel, with the upper sun-facing layer consisting of the same semiconductor materials used on existing rooftop solar panels, while the bottom layer is made of materials that convert a building’s thermal heat into a particular wavelength of infrared light that is able to pass directly through the atmosphere, allowing it to be beamed into space.

Keep reading on New Atlas