The same way a white t-shirt is better to wear than black on a hot summer’s day because it keeps you fresh, buildings with reflective white paint on their exterior also keep them cool. Now, a team of material scientists from the University of California, Los Angeles (UCLA), have produced a new kind of white paint that reflects almost 100% of incoming radiation from the sun.
Over the past years, scientists have explored how white paint could be used to cool down buildings and their surrounding microclimate. In 2012, a NASA study found that white coatings in New York City could drop peak roof temperatures by an average of 43°F (24°C).
Researchers continue to investigate the possibilities in this area. So far, the best-performing white paints on the market reflect 85% of the sun’s heat while absorbing the rest. The UCLA team decided to advance on this by making a few improvements to the formula.
Titanium oxide is the main ingredient in the existing cooling white paints, as it’s very effective at reflecting visible and near-infrared light. However, it absorbs ultraviolet and violet light at the same time, which is something the team wanted to change.
The scientists explored several alternative materials until they found a few successful ones in substituting titanium oxide; among them were barite, polytetrafluoroethylene, and Teflon. They also used fewer polymer binders in the paint, which are typically served to absorb heat.
After the changes were made to the formula, the result was a super white paint with ultra-high cooling capabilities that reflect up to 98% of the sun’s heat. This paint could play a significant role in reducing the use of air conditioners and cutting down the cooling costs of buildings.
Jyotirmoy Mandal, a co-author on the research and UCLA postdoctoral scholar, said, “The potential cooling benefits this can yield may be realized in the near future because the modifications we propose are within the capabilities of the paint and coatings industry.”
The UCLA team published the research on May 29, 2020, in the journal Joule.
