Professor Shanhui Fan presented his latest advances in radiative cooling at annual energy sector conference. Shanhui's radiative cooling harvests electricity from the coldness of the universe, which in turn, can be harvested on Earth for several renewable energy applications. For millennia, humans in regions where the ambient temperature never falls below freezing have used the concept to make ice by burying water at night.

Radiative cooling could have a significant impact on lowering electricity use and boosting output of renewables, but it will require advances in blackbody emitters, materials that absorb heat and radiate the heat at frequencies that send it into space.

"This requires a good blackbody emitter," said Shanhui, "but we can cool objects to a temperature 13 degrees Celsius (55 degrees Fahrenheit) below the ambient temperature with no electricity; it's purely passive cooling."

Radiative cooling systems could, for example, reduce the electricity required for air conditioning by 10 percent to 15 percent, he said. Such systems at night could also generate enough electricity for LED lighting in homes, which would be a significant development for the billion humans without electricity.

Other Stanford faculty research presented includes,

• Professor Yi Cui, discussed new horizons for energy and climate research as part of a panel. To Cui, the big issue is energy storage to enable greater use of intermittent solar and wind power.
• Professor Reihold Dauskardt's Spray-on Solar cells
• Professor Arun Majumdar discussed gigaton-scale solutions for getting to zero greenhouse gas emissions globally from human activity.

Excerpted from Precourt Institute "Stanford at CERAWeek: energy storage, net-zero GHG, radiative cooling and perovskite solar cells"