Could a paint help cool a building so much that it wouldn’t need air conditioners?
Scientists from Perdue University say yes with the development of new white paint, which is claimed to keep surfaces up to 7.7°C cooler than their ambient surroundings.
The offering, which was designed to remove the need for air conditioners and reduce their impact on climate change, is claimed to absorb nearly no solar energy while reflecting heat away from the building.
While normal paint absorbs sunlight, making buildings warmer, the new acrylic, which was developed with calcium carbonate fillers, rejects sunlight and radiates heat into space, according to the study that was published in Cell Reports Physical Science.
Calcium carbonate is an earth-abundant compound, commonly found in rocks and seashells. These calcium carbonate fillers absorb almost no ultraviolet rays due to their atomic structure.
The researchers also note commercial ‘heat-rejecting paints’ currently on the market reflect only 80% to 90% of sunlight and cannot achieve temperatures below their surroundings while the new paint reflects 95.5% sunlight and radiates infrared heat.
Infrared is a type of radiant energy, which is invisible to human eyes but can be felt as heat.
Xiangyu Li, a Postdoctoral Researcher at the Massachusetts Institute of Technology, said: “We’re not moving heat from the surface to the atmosphere. We’re just dumping it all out into the universe, which is an infinite heat sink.”
Joseph Peoples, a Purdue Ph.D. Student in Mechanical Engineering and a Co-Author of the work, commented: “This paint is basically creating free air conditioning by reflecting that sunlight and offsetting those heat gains from inside your house.”