New Car Technology Could Offer Relief from Australian Summers
Australia, famed for its sunshine, is also known for its blistering summer heat. Car owners, in particular, often face the challenge of entering vehicles that feel like ovens.
With 2023 declared the hottest year on record and predictions for 2024 to potentially break those records, many Australians are bracing themselves for another season of extreme heat. The combination of direct sunlight, metal, and glass transforms cars into heat traps, making the driving experience uncomfortable, even in the cooler months.
However, this could be about to change.
The Science Behind the Cool Car
The promise of a vehicle that remains substantially cooler than its surroundings, even before the air conditioning is switched on, is a very appealing prospect.
One way to achieve this is by preventing the car from absorbing as much heat in the first place.
Studies have shown that using white paint can help. According to a 2010 study by Berkeley Lab, white and silver cars consistently stayed up to 6°C cooler than similar black vehicles, resulting in about a 2% reduction in fuel costs due to lower air conditioning use.
However, conventional paint still absorbs some heat, and metals conduct it. Most heat comes from the sun through invisible infrared radiation; current paint technology struggles to deal with this.
New Paint Technology
Nissan is planning to introduce a new type of paint that could revolutionize this problem.
Traditionally, car paint comprises a pigmented base coat, a layer of acrylic polyurethane enamel, and a clear topcoat. Infrared radiation penetrates these layers, causing molecular vibrations that generate heat.
Nissan’s new paint incorporates “synthetic composite materials with structures that exhibit properties not usually found in nature.” In essence, these artificial metamaterials either bounce infrared radiation back into the environment or deflect heat that has already been generated.
This concept is comparable to the function of sunscreen, which both absorbs and reflects UV rays. The new paint utilizes similar materials to sunscreen, such as titanium oxide.
Nissan began a 12-month feasibility study in November. The new paint was applied to a Nippon Airways Nissan NV100 van that spends much of its time parked on the hot tarmac at an airport in Tokyo, which was also outfitted with temperature sensors. While the study is not yet complete, Nissan reports that, when parked alongside another NV100 with regular white paint, the painted van was up to 12°C cooler to the touch on the outside and 5.5°C cooler inside.
Potential Drawbacks?
Dr. Susumu Miura of Nissan’s Advanced Materials and Processing Laboratory, stated, “My dream is to create cooler cars without consuming energy. This is especially important in the EV era, where the load from running air-conditioning in summer can have a sizeable impact on the state of charge.”
One of the drawbacks has been the limited color options, with white being currently the only available choice for the heat-reflective paint. Additionally, this new paint is six times thicker than standard car paint, which could increase the vehicle’s weight.
Despite these minor disadvantages, the new paint offers significant improvements over existing heat-reflective paints used for buildings. Nissan, along with Radi-Cool, is working towards thinner coatings, cheaper application, and integration of the metamaterials in a clear topcoat to offer a wider spectrum of colours.
Miura claims most common challenges for car paintwork, such as resistance to salt, chipping, peeling, and scratching, have already been overcome and meet current commercial standards. Therefore, this new technology could make its way to Australian shores soon, offering a much-needed upgrade to the driving experience during the hot summer months.
