Photo credit: Purdue University / Jared Pike
Purdue University researchers have created the whitest paint yet, and one practical use would be to use it on buildings to help them cool them off enough to reduce the need for air conditioning. This is a followup to the ultra-white paint they unveiled last October, but builds upon it by keeping surfaces cooler than the formulation that the researchers had previously demonstrated. Think of this as the opposite of “Vantablack,” the blackest black material which absorbs up to 99.9% of visible light. Read more for a video and additional information.
The new whitest paint formula is capable of reflecting up to 98.1% of sunlight, compared to the 95.5% of sunlight reflected by previous formulation, and it also sends infrared heat away from a surface at the same time. One component this paint uses is a chemical compound called barium sulfate, which is also used to make photo paper and cosmetics white. The second feature is varying the barium sulfate particles, which means how much each particle scatters light depends on its size, thus having multiple particle sizes allows the paint to scatter more of the light spectrum from the sun.
Infrared camera shows how a sample of the whitest white paint (the dark purple square in the middle) actually cools the board below ambient temperature, something that not even commercial “heat rejecting” paints do. (Purdue University/Joseph Peoples)
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.
