A team of engineers at Indiana’s Purdue University have created an “ultra-white” paint that is capable of reflecting up to 98.1% of sunlight, that could potentially negate the need for air conditioning and even reduce carbon emissions if used on a mass scale.
Developed as part of a six-year project, the researchers say that if the paint covered a 93sqm roof area it would be able to create a cooling power to ten kilowatts, far more powerful than domestic air conditioners.
The paint is made with a chemical compound called barium sulfate, that is used within cosmetics and photo paper to make them white. The barium sulfate particles are made up of different sizes which scatter sunrays and are able to cool immediate surrounding surfaces. The size of the particle determines how much light it scatters, so a wider range of particle sizes allows the paint to scatter more of the light spectrum from the sun.
Using high-accuracy temperature reading equipment called thermocouples, the researchers demonstrated outdoors that the paint can keep surfaces -7 degrees C cooler than their ambient surroundings at night. It can also cool surfaces -13 degrees C below their surroundings under strong sunlight during noon hours.
The researchers said the new white paint was so white it was the equivalent of the blackest black, "Vantablack," which absorbs up to 99.9% of visible light.
Xiangyu Li, a postdoctoral researcher at the Massachusetts Institute of Technology, who worked on this project as a Purdue Ph.D. student in Ruan’s lab, says that after looking at various products and their elements that barium sulfate would be perfect for the revolutionary paint.
“We looked at various commercial products, basically anything that’s white,” he says.
“We found that using barium sulfate, you can theoretically make things really, really reflective, which means that they’re really, really white.”
Patent applications for the paint formulation have recently been filed through the Purdue Research Foundation Office of Technology Commercialization. The research program was supported by the Cooling Technologies Research Center at Purdue University and the Air Force Office of Scientific Research. The research was performed at Purdue’s FLEX Lab and Ray W. Herrick Laboratories and the Birck Nanotechnology Center of Purdue’s Discovery Park.
Text & images: CNN