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Presenting the ‘whitest paint’ that is literally the coolest, too

By PINKY S. ICAMEN Published Apr 21, 2021 7:56 pm

According to researchers, this white may be the closest equivalent to the blackest black, “Vantablack.”

In an effort to curb global warming, engineers at the Purdue University in Indiana spent six years creating the whitest paint yet that can drop the temperature in buildings, which would make them cool enough to rely less on air conditioning.

According to lead researcher Xiulin Ruan, professor of mechanical engineering at Purdue, if the paint is used to cover a roof area of about 1,000 square feet, it is estimated one could get a cooling power of 10 kilowatts, which is more powerful than the central air conditioners used in most houses.

The recently unveiled whitest paint is said to reflect up to 98.1% of sunlight that sends infrared heat away from a surface at the same time, compared to the typical commercial white paint that is designed to reject heat that only reflects 80 to 90% of light.

Researchers consider this paint as the closest equivalent to Vantablack—developed by Surrey NanoSystems in 2014 for aerospace purposes—which absorbs 99.9% of visible light.

An infrared camera shows how a sample of the whitest white paint (right mage) actually cools the board below ambient temperature, something that not even ‘heat rejecting’ paints do. Photo from Purdue University/Joseph Peoples

One of the things that makes the whitest paint extremely white is the high concentration of a chemical compound called barium sulfate, which is also used to make photo paper and cosmetics white.

Because of its extreme aesthetic quality, researchers said that the paint is also the coolest on record.

In their tests, researchers found that when the paint is used to cover the roof, it can reduce the surface temperatures of buildings by 4.5 degrees Celsius below the ambient temperature. It can also cool surfaces 8 degrees Fahrenheit below their surroundings under strong sunlight at noon.

The researchers also found that the paint is effective as it worked in the middle of winter. “During an outdoor test with an ambient temperature of 43 degrees Fahrenheit, the paint still managed to lower the sample temperature by 18 degrees Fahrenheit.”

The research team has already filed a patent for the whitest paint’s formulation through the Purdue Research Foundation Office of Technology Commercialization.