Purdue researchers Ziulin Ruan (left) and Joseph People showing infrared cameras on white paint samples on the roof.
Purdue University Photo / Jared Pike
Ultra-black coatings and ventablake-like paints Has gained a lot of attention in recent years. Now what the world needs is cooling (we’ve hit an unprecedented point in global warming), and new white paint developed by Purdue University engineers can help.
Purdue said in a statement this week that the paint reflects 95.5% of sunlight and can “keep the surface 18 degrees Fahrenheit colder than the area around them.” It’s something that commercial heat-reflecting white paint couldn’t achieve.
The researchers published their findings in the journal Cell Reports Physical Science.
“Mainly because sunlight heats ceilings and walls and makes the interior of your home feel warm. Your air conditioning kicks in. This paint basically creates free air conditioning by reflecting that sunlight and compensating for those heat benefits from inside your home.” Study author Joseph Peoples.
Developing paint was a multi-year process that involved many tests of various paint formulations. Primarily as a component, the team eventually struck up calcium carbonate (a compound found in chalk, limestone and the Seychelles).
The radiative cooling paint developed at Purdu appears purple on the left, showing a lower temperature in direct sunlight than the commercial white paint sample on the right.
Purdue University Image / Joseph Peoples
Engineers compared the new paint to commercial white paint by looking at samples with infrared cameras. The radiative cooling paint appears purple in the image, indicating that it stays cool in direct sunlight.
The team is waiting for the future where the paint can be applied to houses, roofs, cars and even roads. It can help reduce the demand for energy-hungry air conditioning in buildings.
“Paint will send heat not only away from the surface, but also from Earth into deep space where heat travels at the speed of light indefinitely. In this way, heat in the atmosphere will not be trapped and will contribute to global warming,” Purdue said.
The project is a new entry into the field focused on developing cooling materials, coatings and paints. A passive cooling film, created by researchers at the University of Colorado Boulder, does the same thing by dissolving heat and cooling substances in the atmosphere at lower temperatures, like Purudu paint.
The team is also investigating whether it can create other colors with similar cooling properties. Now the new paint just needs a compelling name like Vantablake. How about Winterhite?
