Cooling panel sends excess heat back into outer space

Some diagrams and calculations

Scientists have found a way to cool houses without air conditioning — and without using any power at all.

Shanhui Fan, professor of electrical engineering at Stanford University, and graduate students, Aaswath Raman, and Eden Rephaeli, are working on a cooling panel that could possibly replace your air conditioner.

How? By radiating the vast majority of incoming sunlight into the outside world.

“The structure basically does two things: It radiates the heat out in the atmosphere into outer space, and the device reflects sunlight to ensure that the sunlight does not heat up the device itself,” explained professor Fan, a Ph.D. in physics from the Massachusetts Institute of Technology.

The device is a metal-dielectric photonic structure capable of radiative cooling in daytime outdoor conditions. The structure behaves as a broadband mirror for solar light, while simultaneously emitting strongly in the mid-infrared within the atmospheric transparency window. What that means: It reflects visible light, and also radiates heat back out with a frequency that allows the infrared waves to pass unimpeded through the atmosphere, back out into space. As a result, it achieves a net cooling power in excess of 100 watts per square meter at ambient temperature.

Furthermore, we’re told by the team that the panel will require no electrical input. Essentially, it will sit on the top of the roof of your house and keep you cool, even on the hottest of days, without drawing any power.

The three-member team recently published its findings, and hopes to roll out an experimental prototype within a few months. They’ve spent a year doing extensive simulations and theoretical calculations.

The initiative is supported by Department of Energy. “There’s been quite a bit of interest from companies,” Fan told VentureBeat, without disclosing any names.

Besides commercial use, the product could be put to good social use.

“We are building a prototype as we speak,” said Fan.

Image Credit: Prof. Shanhui Fan