Aaswath Raman is Getting Free Cooling Straight from the Sky

Aaswath Raman is joining the Department of Electrical and Systems Engineering next month. He’s also the co-founder and chief scientific officer of SkyCool Systems. There, his background in optics and materials science have allowed him take an ancient idea and apply it to a pressing, modern-day problem.

Between air conditioning, food storage, and keeping powerful computers from melting down, cooling represents a huge and growing slice of the humanity’s energy budget. But prior to the advent of electricity, people all over the world used radiative cooling to turn water into ice, even when ambient temperatures on the ground never drop below the freezing point. At night, icehouses with specialized architecture and materials caused heat to radiate upwards into colder parts of the sky, cooling water inside enough to freeze.

Raman’s research into nanoscale photonic structures allowed for the same process to occur during the day, by developing artificial optical materials that don’t absorb sunlight, and at the same time emit thermal radiation in the long-wave infrared part of the electromagnetic spectrum.

“When you do that, it can stay up to 50 degrees colder than the air temperature, even if the sun is shining on it,” Raman said. “So what we have then is a completely non-evaporative, zero electricity way of getting below the air temperature — essentially, free cooling.”

Last month, Raman described this approach at the New York Times’ ClimateTECH conference, “a groundbreaking summit that brings together influential leaders from key industries to assess bold, cutting-edge technologies that could help keep global warming below the two-degree threshold — the widely acknowledged danger zone for the planet.”

Raman is one of the thirty new faculty members who have or will join Penn Engineering in a two year span.

“I’m excited to join Penn and explore how we can harness light and heat in new, unexpected ways to enable more sustainable and efficient technologies,” he said.