Summer in Japan is getting hotter and hotter, the heat insulation ability of window film is no longer sufficient. Cars parked under the scorching sun become like huge ovens. in August, Nissan delivered the testing result of a new cooling paint, claiming it can reduce temperature by 5 to 12 degrees Celsius. This not only provides more comfort, but also reduces the energy consumption of air conditioners. 

New developments have progressed from the laboratory to workability testing. Since November 2023, Nissan has begun outdoor testing at Tokyo Haneda Airport, applying cooling paint to ANA’s airport service vehicles. These vehicles, which are Nissan NV100 models, frequently operate on the airport tarmac—an area with no trees, making it an ideal location for testing under high-temperature conditions.

Nissan demonstrated that the results of outdoor testing were promising: the temperature on the vehicles surface was reduced by 12 degrees Celsius, and the temperature inside the vehicles was reduced by 5 degrees Celsius. 

Nissan pointed out that the cooling coating is particularly effective on vehicles that parked under the sun for extended periods. People feel a noticeable chill upon entering these vehicles, reducing the needs to turn the air conditioner to a high setting. This helps minimize the load on engines or the electricity consumption in electric vehicles. 

Developing advanced materials while considering vehicle characteristics 

The new cooling paint is made from advanced materials known as metamaterials. These are a human-made structures with properties that natural materials do not possess. 

Nissan explained that cooling paint contains two types of microstructural particles. One type reflects near-infrared (NIR) rays from sunlight, reducing heat, while the other represents the main breakthrough technology in this development. It generates electromagnetic waves that counteract sunlight and transfer heat from the vehicle’s surface to the atmosphere. 

The new technology is developed through a collaboration between Nissan and Radi-Cool. According to an AP report, Radi-Cool is a Chinese company specializing in cooling films and fabrics. They collaborate with several Japanese companies on products like cooling hats and umbrellas, and Nissan is their sole partner for developing vehicle cooling paint.  

The development of the cooling paint is led by Shinichi Miura, Senior Manager of the Advanced Materials and Manufacturing lab at Nissan’s R&D center. Radiative cooling materials also widely used in building coatings. The focus of this development is not only to adapt the material for vehicle coatings but also to reduce the thickness of coating. Currently, the cooling paint sample is six times thicker than standard automotive coatings and needs to be reduced further to meet commercial standards. The team aims to apply this cooling paint to commercial vehicles, such as trucks and ambulances, that need to be driven nder the scorching sun for extended periods. 

References:
Nissan（2024.8.6），Nissan trialing cool paint technology
Japan economic news（2024.8.6），日産自、自動車用自己放射冷却塗装の実証実験を公開
AP（2024.8.6），Japan’s Nissan is developing ‘cool paint’ for cars to keep drivers cooler

Source: Environmental Information Center