Nissan this week showed off in Japan what it calls “cool paint” to keep the interior of vehicles cooler. The coating is six times thicker, making commercializing the innovation still a challenge.
The company’s announcement came as Japan was experiencing sweltering temperatures. Nissan tested the paint on vehicles driving through Tokyo’s Haneda Airport, a location with many unshaded areas (ideal for evaluating the technology).
The vehicles with the special paint looked like normal cars (in fact, they are white like any other) but the fresh paint reduced the temperature of the cars’ roof panels by 12 degrees and the interiors of the test vehicles were 5 degrees Celsius cooler, according to Nissan. These lower temperatures would be an advantage especially for electric cars, where the energy used by air conditioning affects range more.
Cooling materials are already used in buildings, where the material is applied with a paint roller. Nissan’s challenge was to make this specialized paint sprayable and clear-coatable, like regular car paint.
Nissan claims its cold paint contains a metamaterial (defines it as “synthetic composite materials with structures that exhibit properties not normally found in nature.” It consists of two types of particles in the paint.
- First particle: Reflects near-infrared rays from sunlight that would normally generate heat in the molecules of traditional paint.
- Second particle: Considered by Nissan as “the real breakthrough”, it creates electromagnetic waves that counteract the sun’s rays, redirecting the vehicle’s energy into the atmosphere.
Nissan has developed this innovation with Chinese company Radi-Cool, which created a film, fabric and coating that reduce heat. The company already works with other Japanese companies that offer hats and umbrellas that give a cooler feeling, but this is the first time it has partnered with a car manufacturer.
Susumu Miura, a manager at Nissan’s Research Center who led the project, said there were no discernible negative effects on people’s health from the electromagnetic waves emitted by the paint. Those waves are all around us, he said.
“My dream is to create cooler cars without consuming energy,” he said.
