Summer is fast approaching, temperatures are rising, and for some people, the heat could become bothersome in the upcoming months. If you don’t own an air conditioner or you’d rather not have it on for long hours every day to save energy, you might be excited to learn that there is a novel and very interesting solution to the heat problem.
Scientists recently developed an extremely white paint that reflects 98.1 percent of sunlight and cools itself by radiating heat into outer space. The novel formulation could become a cheap and green way to cool down buildings. All homeowners have to do is simply paint their roof. The ultra-reflective paint was developed by Xiulin Ruan, a professor of mechanical engineering at Purdue University in Indiana, and his colleagues. It is an improvement of a similar formula the team created last year, which reflected 95.5 percent of light.
The new paint’s extreme whiteness is due to very high levels of barium sulfate, a compound that occurs in the mineral barite. It is also a key ingredient in photographic paper and cosmetics. The chemistry of barium sulfate as a white pigment has been known since the 18th century, but Ruan and his team adjusted the particle size to create a substance that reflects heat better.
The barium sulfate particles present in the new paint are of different sizes, which is what gives it the broadest spectrum scattering of light and contributes to its high reflectibility.
The new and improved ultra-white paint also absorbs less than half of the amount of energy from the sun compared to the previous version developed by the lab. The amount of sunlight absorbed by the new paint is lower than the amount of energy it radiates through the atmosphere and into deep space, so the material coated with this novel paint actually becomes cooler than its surroundings.
The team hopes that this new technology can lower global carbon emissions by reducing the need for air-conditioning, as well as provide relief for those living in hot areas and are unable to afford air conditioning. According to Ruan, if the paint is used on a 930 square meter roof, the cooling effect of the paint is more powerful than that of an air conditioner. The paint also sends the energy away to outer space rather than leaving it trapped on Earth as an AC unit does. “Traditional air conditioners leave the heat on Earth’s surface, it’s just moved from the inside of your house to the outside,” Ruan said to New Scientist.
The painted surfaces will need to be kept clean of dust and dirt to retain their reflective properties, which is a challenge Ruan’s team is currently working on. Further testing of the product is still needed, but Ruan hopes that ultra-white paint could appear on the market in a year or two.
We will definitely continue following and updating you about the developments of this new technology, as it really has the potential of making a difference in the world.
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