If you walk up to the top of the Grocery Outlet in Stockton, California in the middle of summer and lay your hand on the weird glossy black panels you find there, you’ll be surprised to find them so cold to the touch like an underground fuse box. .
Installed by a company called SkyCool Systems, they are the first of a new type of cooling technology that radiates heat through the atmosphere and lowers the ambient temperature by about 10°F.
Radiant cooling is what happens when electromagnetic waves, which we call heat, leave an object. This is a phenomenon that exposes you to heatstroke in the desert by day and hypothermia by night; the absorbed heat evacuates the landscape at sunset and leaves Earth’s atmosphere into space without water vapor trapping it.
A UCLA scientist argues that if a certain spectrum of warming rays were emitted into the atmosphere during the day, whatever was left would cool off and potentially provide an alternative to traditional air conditioning.
About 7% of global greenhouse gas emissions are caused by cooling systems for residential buildings and transportation, but as global temperatures continue to rise, the use of cooling systems for homes and businesses is expected to triple in the coming years. .
SkyCool’s luminous panels can absorb all the sunlight that creates heat, and instead of returning it to a rotating cauldron with gas that heats the planet, they eject it into space.
Aaswath Raman, a materials scientist at the University of California, Los Angeles, found that radiative cooling technologies such as sheets and special reflective varnishes had previously been studied but were later abandoned as impossible.
The idea is that if something gives off heat even in broad daylight, it can save thousands of cooling costs. Raman decided to apply for a grant to the Agency for Advanced Research Projects-Energy or ARPA-E, a branch of the Department of Energy.
Despite the layers of material and all the water vapor and CO2 that make up the atmosphere, 8 to 13 microns of infrared radiation penetrates it as if it were light that no one can leave the atmosphere to ensure that the heat is dissipated, not a problem for anyone else.
With colleagues from Stanford’s engineering department, led by Shanhui Fan, he created ultra-thin sheets of silica, glass and hafnium dioxide, a coating agent used in optics, one meter long and two meters wide.
Placed on the roof, they found that their prototype panels were getting warmer in the sun’s shadow – a counter-intuitive reaction to what to expect because the radiation was blocked by the shading material. Plus, the panels feel cool under the hot summer sun.
When the film is attached to the hood, it not only reflects the sun’s rays, but also radiates some of the engine’s heat. When placed above the point where the water pipe runs through the building, it cools the water inside and reduces the load on the air conditioning system.
After a trip to Mumbai, India showed the growth rate of the domestic air conditioning market, Raman needed to make sure panels and foils were cheap enough for use in developing countries near the tropics, where they are most common.
In Stockton, Grocery Outlet spends $40,000 a year cooling off between frozen islands and its deli. SkyCool panels are placed on the roof and now save about $5,800 a year.
The Washington Post reports that Raman and SkyCool Systems are seeking grants as part of a project to replace all school air conditioners to see if their own special film can be the building’s primary coolant, while National Geographic adds that several scientists have created a model suggesting that if only 1.5% of the world were covered with these panels and that if these panels could be held long enough, will reflect all the additional heat created by the climate crisis.