Eli Goldstein, a fresh-faced cofounder of SkyCool Systems, pulled open the garage door on the side of the Stanford spinout’s cramped workspace in Burlingame, California, and rolled a set of square silver panels into the parking lot.

They were tilted toward the sun, covered in what looked like perfectly creaseless aluminum foil and attached to a metal frame holding an array of pipes, tubes, and thermometers.

Temperatures reached 104 ˚F on the San Francisco Peninsula that day, the start of a rare and scorching Bay Area heat wave. Stepping in front of the panels felt like walking past an open oven.

Which is precisely the point. SkyCool’s panels are essentially high-tech mirrors, designed to cool buildings far more efficiently than traditional air-conditioning systems by exploiting an odd quirk of optics that allows a narrow band of radiation to escape into space (see “The Sky May Hold the Secret to Efficient Air-Conditioning”). Depending on the application and climate conditions, the technology could cut the energy used to cool structures by 10 to 70 percent, shrinking one of the biggest single demands on the U.S. grid and reducing greenhouse-gas emissions accordingly.

View this article in full at: MIT Tech Review