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Nissan has launched a paint that reportedly keeps cars up to 12 degrees cooler as extremely high temperatures become the norm around the world.

The “cool paint” launched Tuesday promises to reduce both the outside and inside temperatures of cars, offering a potential solution to the discomfort and energy consumption associated with overheated vehicles as summers become longer and hotter.

The paint is six times thicker than standard automotive paint, a property that currently poses a challenge for mass production, but the company says the benefits are substantial.

Traditional commercial white paint, usually made with titanium dioxide nanoparticles, reflects 80-90 percent of sunlight but still absorbs some heat, limiting its cooling effect during the day. These paints are generally applied at a thickness of about 120 µm (0.12 mm or about 0.0047 inches).

Tests on vehicles at Tokyo’s Haneda Airport, a location known for its shadowless expanses, found that the paint could make the cars noticeably cooler.

The technology reduced the roof panel temperature by 12°C (22°F) and the interior temperature by 5°C (9°F).

Nissan’s new paint reflects sunlight more effectively and generates electromagnetic waves that deflect the sun’s rays, directing energy away from the car.

This approach can not only keep cars cooler, but can also reduce reliance on air conditioning and thus save energy.

Cooler vehicles can also reduce the load on engines and extend the life of electric vehicle batteries, an important consideration in today’s automotive industry.

Nissan’s paint was developed in collaboration with Radi-Cool, a Chinese company known for its cooling technologies. The paint is part of a broader initiative to integrate temperature-reducing materials into everyday products.

Radi-Cool has also developed coolants and coatings for various applications, including hats and sunshades. Nissan is currently the only Japanese automaker to work with Radi-Cool, marking a unique collaboration in the industry.

The announcement of the innovative technology comes at a crucial time, as Japan is experiencing one of the hottest summers on record. Global heat records are being broken every month, with the last 13 months being the hottest on record.

People who drive a lot outside in the heat find it increasingly difficult to cope with the temperatures. As a result, they use the air conditioning more often and therefore consume more energy.

Automakers have come up with innovative ideas to reduce the temperature inside vehicles without relying on traditional, energy-consuming methods. This is not only an environmental measure, but also a reason for public health.

Susumu Miura, manager at Nissan’s research center, emphasized the safety of the electromagnetic waves emitted by the paint, assuring that they have no harmful effects on health.

“My dream is to create cooler cars without consuming energy,” Miura said.

Toyota Motor Corp. is also experimenting with paints that lower cabin temperatures, focusing on colors that refract the sun’s rays.

In 2021, researchers at Purdue University created a white cooling paint using barium sulfate nanoparticles. The paint was able to reflect 98.1 percent of the sun’s rays and emit more infrared heat than it absorbed.

But the paint works best in a 400 µm thick layer, which is equivalent to 0.4 mm or about 0.016 inches, almost four times thicker than the typical 120 µm layer on vehicles.

Study researcher George Chiu said at the time that the paint “has the potential to cool the exterior of airplanes, cars or trains.”

“An aircraft sitting on the tarmac on a hot summer day doesn’t have to run the air conditioning as hard to cool the inside, which saves a lot of energy,” he said.

People living in warm climates have been painting buildings white for centuries to keep them cool. White or silver coatings reflect the sun’s heat-producing infrared rays.

In fact, cool roofs and house paints have become increasingly popular in countries like India. Also known as reflective roof coating or thermal insulation paint, these paints have successfully reduced temperatures in homes by 5C.

However, companies are struggling to make these paints more easily applicable to cars and more widely available at competitive prices.

Another type of paint was developed by Vantablack, a formula developed by researchers in the United Kingdom and used on a BMW X6 SUV in 2019. The paint is said to absorb up to 99 percent of the light that falls on it.

“To achieve this level of subambient radiative cooling, we had to apply a layer of paint at least 400 microns thick,” Purdue study lead researcher Xiulin Ruan said in a 2021 press release.

“That’s fine if you’re painting a sturdy, stationary structure, like the roof of a building. But in applications with precise size and weight requirements, the paint needs to be thinner and lighter.”

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Nissan’s “cool paint”

1. Metamaterials: The paint incorporates advanced metamaterials, which are synthetic composite materials with unique properties not typically found in nature. These materials are engineered to interact with light and heat in specific ways.
2. Reflecting Near-Infrared Rays: One of the key components of this paint is its ability to reflect near-infrared rays from the sun. Near-infrared rays are a significant source of heat, and by reflecting them, the paint reduces the amount of heat absorbed by the car’s surface.
3. Creating Electromagnetic Waves: The paint also contains particles that create electromagnetic waves. These waves counteract the sun’s rays by redirecting the energy away from the vehicle and into the atmosphere. This process helps to further reduce the heat buildup on the car’s exterior.
4. Temperature Reduction: As a result of these combined effects, cars treated with this paint can stay up to 12°C (21.6°F) cooler on the exterior and up to 5°C (9°F) cooler inside compared to those with traditional paint¹²³.
5. Energy Efficiency: By keeping the car cooler, the need for air conditioning is reduced, which is particularly beneficial for electric vehicles as it helps conserve battery life.

This innovative paint is still in the trial phase, but the results so far have been promising. It’s a great example of how technology can help us adapt to and mitigate the effects of climate change.

How Does Nissan Cool Paint Work

1. Temperature Reduction:

   • Cool Paint: Can reduce the exterior surface temperature of a car by up to 12°C (21.6°F) and the interior temperature by up to 5°C (9°F) compared to traditional paint¹²³.
   • Traditional Paint: Does not have significant temperature-reducing properties and can lead to higher heat absorption, making the car hotter both inside and out.

2. Energy Efficiency:

   • Cool Paint: By keeping the car cooler, it reduces the need for air conditioning, which is particularly beneficial for electric vehicles as it helps conserve battery life².
   • Traditional Paint: Higher interior temperatures often require more air conditioning, leading to increased energy consumption and reduced efficiency, especially in electric vehicles.

3. Material Composition:

   • Cool Paint: Uses advanced metamaterials that reflect near-infrared rays and create electromagnetic waves to counteract the sun’s heat¹².
   • Traditional Paint: Typically lacks these advanced materials and primarily focuses on aesthetics and basic protection against the elements.

4. Application and Durability:

   • Cool Paint: Currently thicker than traditional automotive paint (120 microns vs. 20 microns per layer), but Nissan is working on making it thinner while maintaining its cooling properties. It also shows resistance to chipping, peeling, scratching, and chemical reactions¹².
   • Traditional Paint: Generally thinner and more established in terms of application techniques and durability. It often includes a topcoat for added protection and aesthetic appeal.

5. Color and Aesthetics:

   • Cool Paint: Currently available in white, but Nissan aims to develop versions that can be applied in various colors and with a clear topcoat¹².
   • Traditional Paint: Available in a wide range of colors and finishes, including metallic and pearlescent options, with well-established topcoat applications for added shine and protection.