How would you like to not ever need air conditioning in your car? Even in 100-degree heat? A new paint formula recently created could help buildings and cars rely much less on air conditioning.
Purdue University engineers have come up with revolutionary paint. It’s the whitest white ever made. Now researchers are saying that with this paint applied to cars or buildings it lessens the need for air conditioning.
The ultra-white paint formulation keeps anything it is painted on much cooler
The ultra-white paint formulation that Purdue came up with keeps anything it is painted on much cooler. “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,” Xiulin Ruan told Scitechdaily. He’s a Purdue professor of mechanical engineering. “That’s more powerful than the central air conditioners used by most houses.”
Remember “Vantablack?” It is that black paint that absorbs 99% of visible light. Well, this whitest white paint is the exact opposite of Vantablack. That is, it reflects 98.1% of the sun’s rays.
It took six years of research to come up with the whitest white paint. It actually has its origins from research done in the 1970s. Back then the research was being conducted on developing radioactive cooling paint.
This is the complete opposite of how most white paint reacts
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Infrared heat is directed away from whatever is painted with the whitest white. That’s completely the opposite of how typical white paint reacts. It gets warmer instead of cooler unless specially designed to reject heat.
That specially formulated white paint still only reflects between 80-90% of sunlight. And it doesn’t cool the surface it is painted onto. It also means it doesn’t cool what is surrounding that kind of paint.
So, what makes this whitest white so extremely white? It is the barium sulfate that increases its cooling properties. Barium sulfate is also used in making photo paper and also what makes certain cosmetics white.
Using barium sulfate makes things more reflective
“We looked at various commercial products, basically anything that’s white,” said Xiangyu Li, a Purdue Ph.D. student in Ruan’s lab. “We found that using barium sulfate, you can theoretically make things really, really reflective. That means that they’re really, really white.”
Another reason that his white paint is so reflective is that the barium sulfate particles are of different sizes. The larger barium sulfate particles scatter light better. So a range of particle sizes helps to scatter more of the sun’s light spectrum.
Concentrating particles in the paint is best for making white so reflective
Concentrating the particles in the paint is best for making the white so reflective. But the downside is that higher particle concentrations make for an easier-to-peel paint. So from a practical standpoint, it is not particularly good at being white paint.
It was found that the paint keeps the surfaces it is painted on cooler. At night the paint keeps surfaces 19-degrees cooler than anything else surrounding the painted object. In extreme heat, it cools the surface 8-degrees lower than surrounding objects.
We wonder how much lower temperatures could be reduced with more experimentation? If these experiments in white paint could reduce heat even further it could render air conditioning obsolete. Or, at least reduce the need to crank up the air in your car or house.