A cooling automotive paint

Car manufacturer Nissan developed an automotive paint that helps lower the vehicle’s ambient cabin temperature in summer, reducing the energy usage of the air conditioning system.

If you have ever stepped into a car in summer, you know the car interior can get hot. To cool the vehicle, the quickest way, especially in newer cars, is to turn on the air conditioning.

To both help lower the temperature and reduce energy usage, Nissan developed their cooling paint. The coating incorporates synthetic composite materials with structures that exhibit properties not usually found in nature. This metamaterial features two microstructure particles that react to light. One particle reflects near-infrared rays in the sunlight that would typically cause molecular level vibrations within the resin of traditional paint to produce heat.

The paint was developed in partnership with Radi-Cool, a specialist in radiative cooling products. While still in the testing phase, the initial results already show some promise. Parked side-by-side under the sun, a vehicle treated in Nissan’s cool paint has shown yields of up to a 12-degree Celsius reduction in exterior surface temperatures and up to 5-degree Celsius cooler interior, compared to a vehicle featuring traditional automotive paint. The second creates electromagnetic waves that counteract the sun’s rays, redirecting the energy away from the vehicle into the atmosphere. Combined, the particles in Nissan’s cool paint reduce the transfer of heat into surfaces such as the roof, hood, doors and panels.

Paint for radiant cooling isn’t new per se. However, this is the first time a paint was developed for the automotive industry. The paint had to be appliable via a spray gun rather than a roller and be able to incorporate a clear top coat.

Not all hurdles have been taken yet, though, Currently, the paint has a thickness of 120 microns, which is six times thicker than typical automotive paint.

Photos: Nissan