The whitest color in the world – seen in this year’s edition of the Guinness World Records and “The Late Show With Stephen Colbert” – makes the surface cool enough that they can reduce the need for air conditioning. Now, Purdue University researchers who developed paint (The world’s cleanest paint is now thinner than ever) have developed a new, thin, lightweight system that’s perfect for drawing heat away from cars, trains and airplanes.
“I’ve been contacted by everyone from airplane designers to architects to clothing and shoe companies,” said Xiulin Ruan, a Purdue engineering professor and graphic designer. “They usually have two questions: where can I buy it and can you make it thinner?”
The world’s purest paint (The world’s cleanest paint is now thinner than ever) uses barium sulfate nanoparticles to reflect 98.1% of sunlight, making the surface cooler by 4.5°C below ambient temperature. Cover your roof with this color and you can cool your house with less air conditioning, but there is a problem.
“To achieve this level of air cooling below room temperature, we have to add a layer of at least 400 microns,” Ruan said. “It’s good if you’re painting a solid structure, like a roof. But in applications that have a large size and weight requirement, the color will be small and light.
That’s why Ruan’s team started experimenting with other materials, making the ends of the materials not radiate sunlight. Their new formulation is a nanoporous paint that includes hexagonal boron nitride as a pigment, a material commonly used in lubricants. This new color achieves almost the same signal of the sun (97.9%) with a single coat of 150 micron color.
Their research has been published in Cell Reports Physical Science.
“Hexagonal boron nitride has a high index of refraction, which results in the ability to scatter sunlight,” said Andrea Felicelli, a Purdue mechanical engineering doctoral student working on the project. “The particles of this material also have a special shape, which we call nanoplatelets.”
Ioanna Katsamba, another engineering PhD student at Purdue, conducted computer simulations to understand whether nanoplatelet morphology provides benefits. “The models showed us that nanoplatelets are more efficient at absorbing solar radiation than the spherical nanoparticles used in previous cooling systems,” Katsamba said.
The paint also encases air spaces, making it porous at the nanoscale. This low density, combined with thinness, gives another great advantage: reduce weight. The new paint costs 80% less than barium sulfate paint, but achieves similar solar reflectivity.
“This light weight opens the door to all kinds of applications,” said George Chiu, a Purdue engineering professor and inkjet printing expert. “Now this paint can cool the outside of an airplane, bus or train. An airplane sitting on the tarmac on a hot summer day won’t run its air as well hard to cool the room, thus saving a lot of money. energy. The aircraft should also be as light as possible, and this drawing can be one of them.
As for the big question again – where can I buy paint? – Ruan explains. “We are in discussions now to bring it to market,” he said. “There are still a few problems to solve, but progress is being made.”
Either way, these Purdue researchers are excited about what paint can accomplish. “Using this color will help cool the face and reduce the need for cold air,” Ruan said. “This not only saves money, but also reduces energy consumption, which reduces greenhouse gas emissions. And unlike other cooling methods, this color increases all the heat in the deep space, which makes our world cool instantly. It’s amazing that graphics can do everything.
