Xiulin Ruan is a professor of mechanical engineering at Purdue University, and he and his team have developed an extraordinary white paint that could become one of the major tools to help reflect sunlight back into space, and cool our planet.
With astounding reflective properties, the paint can dramatically cool outdoor surfaces that are normally heated from the sun. It’s literally the coolest paint on the planet.
The Quest for Ultra-White Paint
For years, scientists have sought to develop materials that can reflect sunlight effectively, thereby reducing heat absorption and cooling the surrounding environment. As the demand for cooling solutions in buildings continues to rise, the need for more energy-efficient and sustainable alternatives becomes increasingly urgent. Purdue University’s breakthrough comes as a ray of hope in this relentless pursuit.
The Science Behind the Whitest Paint
The innovative paint developed by Purdue’s research team utilizes a novel formulation to achieve its ability to reflect so much sunlight. Traditional white paints typically contain titanium dioxide, a pigment that reflects a significant portion of the incoming sunlight. However, the world’s whitest paint takes this concept further by incorporating barium sulfate, which help it become ultra-effective at bouncing the sun rays back into space. These reflective properties don’t heat the surrounding air either, unlike traditional cooling devices, like air conditioning.
The New York Times describes the impressive attributes of this paint:
“The paint’s properties are almost superheroic.
It can make surfaces as much as eight degrees Fahrenheit cooler than ambient air temperatures at midday, and up to 19 degrees cooler at night, reducing temperatures inside buildings and decreasing air-conditioning needs by as much as 40 percent.
It is cool to the touch, even under a blazing sun, Dr. Ruan said. Unlike air-conditioners, the paint doesn’t need any energy to work, and it doesn’t warm the outside air.”
The potential cooling benefits of Purdue’s white paint are immense. When applied to the exterior of buildings, it can significantly reduce indoor temperatures by reflecting a substantial amount of the sun’s energy back into space. The paint’s ability to maintain lower surface temperatures than traditional coatings, even in direct sunlight, holds the promise of reducing the need for air conditioning in buildings, thereby slashing energy consumption and utility costs.
Mitigating the Urban Heat Island Effect
Beyond cooling individual buildings, the widespread adoption of the world’s whitest paint could also have a collective impact on entire urban environments. Cities are particularly prone to a phenomenon known as the “urban heat island” effect, where urbanized areas experience higher temperatures than their rural counterparts due to the concentration of concrete and asphalt, which absorb heat. By coating urban surfaces such as roofs and walls with Purdue’s ultra-white paint, the heat absorbed by these surfaces would be minimized, leading to a cooling effect on a city-wide scale.
“We weren’t really trying to develop the world’s whitest paint,” Dr. Ruan said in an interview. “We wanted to help with climate change, and now it’s more of a crisis, and getting worse. We wanted to see if it was possible to help save energy while cooling down the Earth.”
The implications are awesome. Take, for instance, a large commercial roof, or even a residential roof. If painted with this ultra-reflective paint, the entire building could benefit from cooling, reducing or even eliminating the need to use air conditioning.
Imagine this paint on car roofs, or even highways painted white instead of black. The possibilities are practically endless, and the benefits of the cooling properties are immense.
Dr. Ruan says that he and Purdue are in discussions with a major paint producer, and hope to bring this product to the commercial market within the next one to two years.