US scientists have created the world’s whitest shade of white paint — and it could help combat global warming, the researchers claim.
Engineers at Purdue University in Indiana developed an ultra-white paint they say reflects 95.5 percent of sunlight to keep surfaces up to 18 degrees Fahrenheit cooler than their surroundings.
The team hopes the creation could reduce the need for air conditioning while consuming zero energy.
“It’s very counterintuitive for a surface in direct sunlight to be cooler than the temperature your local weather station reports for that area, but we’ve shown this to be possible,” Purdue mechanical engineering professor Xiulin Ruan said last week while announcing the discovery.
An infrared camera confirmed that the new paint drops below the temp of both its surroundings and its commercial counterpart, the researchers said. Other paints that reflect sunlight only divert between 80 to 90 percent and can’t get to temps below their surroundings.
Formulation of the as-yet-to-be-named acrylic paint was a six-year process that ultimately used calcium carbonate — a compound found in rocks and seashells — as the paint’s filler.
It can even send the reflected ultraviolet light into deep space, according to a paper published in the journal Cell Reports Physical Science.
“Compared to conventional air conditioners that consume electricity and only move heat from the inside of the space to the outdoors, passive radiative cooling not only saves but it also combats global warming since the heat is directly lost to the deep space,” the study reads.
Scientists believe Earth’s surface would cool if the technology — which looks the same as commercial paint — was applied to roads, rooftops and cars across the world. It’s even cheaper than commercial paint and could save about $1 a day in electricity used to cool down a one-story home, according to the Purdue University team.
“Your air conditioning kicks on mainly due to sunlight heating up the roof and walls and making the inside of your house feel warmer,” said Joseph Peoples, a Purdue mechanical engineering student and co-author of the study. “This paint is basically creating free air conditioning by reflecting that sunlight and offsetting those heat gains from inside your house.”
Fewer air conditioners in use equates to less energy produced by coal, which may lead to reduced carbon dioxide emissions, Peoples said.
Additional studies at Purdue are ongoing to evaluate those potential benefits, university officials said.