This is Cool!!

[beecee]

https://phys.org/news/2021-04-whitest-hereand-coolest-literally.html

The whitest paint is here—and it's the coolest. Literally: 

In an effort to curb global warming, Purdue University engineers have created the whitest paint yet. Coating buildings with this paint may one day cool them off enough to reduce the need for air conditioning, the researchers say.

 

In October, the team created an ultra-white paint that pushed limits on how white paint can be. Now they've outdone that. The newer paint not only is whiter but also can keep surfaces cooler than the formulation that the researchers had previously demonstrated.

"If you were to use this paint to cover a roof area of about 1,000 square feet, we estimate that you could get a cooling power of 10 kilowatts. That's more powerful than the central air conditioners used by most houses," said Xiulin Ruan, a Purdue professor of mechanical engineering.

The researchers believe that this white may be the closest equivalent of the blackest black, "Vantablack," which absorbs up to 99.9% of visible light. The new whitest paint formulation reflects up to 98.1% of sunlight—compared with the 95.5% of sunlight reflected by the researchers' previous ultra-white paint—and sends infrared heat away from a surface at the same time.

extract:

 

What makes the whitest paint so white

Two features give the paint its extreme whiteness. One is the paint's very high concentration of a chemical compound called barium sulfate which is also used to make photo paper and cosmetics white.

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