You might think that ultra white paint is white paint. Nothing special, just white paint that has multiple uses in all sorts of situations. However, Xiulin Ruan, a professor of mechanical engineering at Purdue University, has made a new type of white paint. He believes it could significantly cool down buildings without the need for huge levels of electrical consumption that air conditioning requires. That sounds like a fantasy, but an intriguing one.
In 2020, Dr. Ruan and his team unveiled their creation: a type of white paint that can act as a reflector, bouncing 95 percent of the sun’s rays away from the Earth’s surface, up through the atmosphere, and into deep space. A few months after the initial launch, they announced an even more potent formulation that increased sunlight reflection by 98 percent.
The paint’s properties are almost unbelievable. It can make surfaces as much as eight degrees Fahrenheit cooler than ambient air temperatures at midday, and up to 19 degrees cooler at night, reducing temperatures inside buildings, and decreasing air-conditioning needs by as much as 40 percent. It is cool to the touch, even under a blazing sun and, unlike air-conditioners, the paint doesn’t need any energy to work, and it doesn’t warm the outside air. You might think it has to be blindingly white, but it isn’t because it scatters light.
While the paint was originally envisioned for use on rooftops, manufacturers of clothes, shoes, cars, trucks, and even spacecraft, have shown interest.
Last year, Dr. Ruan and his team announced that they’d come up with a more lightweight version that could be used on vehicles to reflect heat. This could reduce the part of fuel consumption that is presently expended on air conditioning units in vehicles.
“We weren’t really trying to develop the world’s whitest paint,” Dr. Ruan said in an interview. “We wanted to help with climate change, and now that it’s more of a crisis, and getting worse, it is even more important. We wanted to see if it was possible to help save energy while cooling down the Earth.”
The paint is at least a year from being ready for commercial production, and work is underway to increase its durability and dirt resistance. Dr. Ruan said the Purdue team has partnered with a company, but can’t yet name it. The team is also developing colored paints that use the ultrawhite as a base. “They will work less ideally than the white, but better than current commercial colors.
White paint has long been used in such hot and picturesque places as Santorini, in the Mediterranean, and the aptly named Casablanca, to cool dwellings, and municipalities are increasingly looking to paint rooftops white. However, Dr. Ruan claims that commercial white paints generally reflect 80 percent to 90 percent of sunlight. This means they still absorb 10 percent to 20 percent of the heat, which in turn warms surfaces, and the ambient air. The Purdue paint, by comparison, absorbs so much less solar heat and radiates so much more heat into deep space that it cools surfaces to below-ambient temperatures.
Geoengineering, like this development of ultra-white paint, has been criticized as a distraction from the root problem: Humans must stop burning fossil fuels to avoid catastrophic effects of climate change.
However, this is part of the usual human trend of seeking THE solution instead of taking advantage of all possible solutions. Waiting for THE solution to materialize wastes valuable time, and only kicks the can down the road. It is also a great excuse not to do anything now. Even if all fossil fuel use stopped immediately, climate disasters would continue to unfold because of the amount of greenhouse gases that are already trapped in the atmosphere. So, yes, we need to work hard on removing those greenhouse gases, and restricting the production of more. However, developments like ultra-white paint could be something we can do now to mitigate some of the problems of global warming. Every little bit helps and, probably more importantly, it could get all of us involved now in addressing the problem instead of sitting back and expecting governments to solve the problem for us. As the old saying goes, the really bad news is, “We’re from the government, and we’re here to help!”
