With emissions regulations getting tighter and stricter, car companies are constantly looking for new ways to reduce those nasty emissions and make cars better for the environment. One way to do this could be to use a newly developed, ultra-white paint that can keep the car’s cabin cool.
This new Ultra White paint can reduce the surface temperature of the cabin by 5–6 °C (41–43 °F), reflecting only 97.9 per cent of sunlight. This is with a thickness of 150 micrometres, which is about 30 micrometres thicker than the ones typically used on production cars.
The key ingredient to making this paint both thin and reflective is the use of hexagonal boron nitride nanoplatelets, which I will pretend to understand. Because of those fancy nanoplatelets, it only needs one coat to get the desired cooling effect.
To put this in perspective, Ziulin Ruan, a professor of mechanical engineering at Purdue University, and his colleagues developed a white paint designed to reflect sunlight. It used barium sulphate nanoparticles instead of the typical titanium dioxide nanoparticles used in most commercial reflective white colours. And it was able to reflect a lot of sunlight but with a thickness of 400 micrometres, more than twice the thickness of this new stuff.
Why is it important to reflect sunlight? Keeping the surface temperature low keeps the cabin temperature down, reducing the need for air conditioning. The use of less air conditioning makes any vehicle more efficient, which means less emissions.
Less air conditioning helps EVs use less battery juice, thus reducing their need to charge and sucking dirty energy from the grid. It may not seem like it makes much of a difference, but if such reflective paints are used collectively, it can have a big impact on overall emissions. So, ultimately, keeping the cabin cool helps keep the planet cool.