Scientists have created a new ultra-white paint that can reflect 95.5 percent of the sunlight that reaches its surface. This incredible property allows something coated in this paint, like a building, to cool below the temperatures of its surroundings even under direct sunlight. An incredible technical achievement that could go towards combatting global warming.
Reporting in the journal Cell Reports Physical Science, the team tested the paint over the course of two days. When the Sun was at its highest point in the sky, the surface covered in the new paint was at least 1.7°C (3.06°F) below that of surrounding objects. At night, it stayed 10°C (18°F) below ambient temperatures.
"It is a persistent task to develop a below-ambient radiative cooling solution that offers a convenient single-layer particle-matrix paint form and high reliability," senior author Professor Xiulin Ruan, from Purdue University, said in a statement. "This is critical to the wide application of radiative cooling and to alleviate the global warming effect."
The ability to cool down objects and buildings is certainly exciting and beneficial to many industries in our warming world. Not just for residential and commercial buildings to keep ambient temperatures cool, but it could help warehouses where perishable products are kept and even data centers preserve their goods. A building covered in this paint would have a lower indoor temperature, reducing the amount of air conditioning needed, too.
The paint is acrylic with a calcium carbonate component. Lacking a metallic component allows the paint to also be used on telecommunication equipment that is kept outdoors, which would help to keep it cool without interfering with signals.
"Our paint is compatible with the manufacturing process of commercial paint, and the cost may be comparable or even lower," added Ruan. "The key is to ensure the reliability of the paint so that it is viable in long-term outdoor applications."
The team is currently planning investigations into how reliable this paint is in terms of environmental factors. It will be exposed to ultraviolet light, dust, water, and detergent, as well as being tested on realistic materials to assess how well it sticks to surfaces to gauge if it has the right properties to replace existing paints.
This is not the only ultra-white paint in the works. Early this summer another ultra-white paint development was announced which is currently being investigated for commercial use.