Ultra-white paint: The sustainable way to cool homes

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  Quantumrun Foresight
• November 3, 2022

Insight summary

One of the most severe effects of climate change is global warming, leading to heat waves and increased demand for carbon-emitting air conditioners. However, a group of researchers has discovered a cooling white paint that might be more effective at cooling entire structures. The long-term implications of this discovery may include increased research for cooling innovation and governments mandating newer buildings to adopt environment-friendly features.

Ultra-white paint context

Global warming occurs when carbon dioxide and other air pollutants accumulate in the atmosphere and absorb sunlight and solar radiation that enter Earth’s surface. Typically, radiation would escape into space, but these pollutants may linger for centuries, trap heat and make the planet warmer. Since the Industrial Revolution, the global average temperature has risen by about 1 degree Celsius (or 2 degrees Fahrenheit).

From the start of accurate recordkeeping in 1880 until 1980, the global average temperature rose by 0.07 degrees Celsius (0.13 degrees Fahrenheit) per decade. However, since 1981, this rate has more than doubled. On average, the global temperature rose by 0.18 degrees Celsius (0.32 degrees Fahrenheit) every decade. 

Aside from limiting the use of fossil fuels, companies are exploring more practical ways to cope with global warming, for instance, using paint on buildings. White paints that are heat-reflective are generally composed of titanium dioxide, which reflects particular wavelengths of light but doesn’t block the sun’s ultraviolet (UV) radiation; this gap enables surfaces to heat up. 

Since 2015, Purdue University researchers have been working with materials that could reflect the sun’s UV rays rather than just trying to improve existing paint varieties that only absorb the rays. The team tried about 100 different materials, eventually deciding on barium sulfate. This component is a recognized UV-reflecting substance used in cosmetics, reflective photo paper, oil paints, x-ray examinations, and other applications. 

Disruptive impact

In 2020, the Purdue University mechanical engineers announced that they had succeeded in creating the whitest paint in existence. The group produced ultra-white paint that reflects up to 98.1 percent of sunlight and simultaneously radiates infrared heat away from a surface. The team hopes that coating buildings with this paint may one day be able to cool them off enough to reduce the need for air conditioning.

According to mechanical engineering professor Xiulin Ruan, ultra-white paint can achieve a cooling power of 10 kilowatts if painted on a roof area of about 1,000 square feet. These numbers are more than what average air conditioning units can provide. 

The ultra-white paint’s two key features are its high concentration of barium sulfate and its production process. The paint’s whiteness also implies that it is the coolest, according to thermocouples’ high-accuracy temperature reading equipment. The researchers tested outside at night and found that the paint can keep surfaces -7 degrees Celsius (19 degrees Fahrenheit) cooler than their ambient environment. In comparison, most commercial white paints available become warmer instead of cooler. Commercial white paints are designed to reject heat, only reflect 80 to 90 percent of sunlight, and cannot make surfaces cooler than their surroundings.

Implications of ultra-white paint

Wider implications of ultra-white paint may include: 

• The transportation and logistics industry using ultra-white paint to cool vehicle fleets, including cars, buses, trains, ships, and airplanes.
• Governments mandating new buildings use ultra-white paint to assist in cooling cities and urban centers.
• The commercialization of ultra-white paint, leading to different companies formulating other versions of the product, which can increase consumer choice and lower prices.
• Ultra-white paint and solar panel manufacturers collaborating to offer package deals for homeowners as solar panels work best in lower temperatures.
• Decreasing production of air-conditioning units for countries with cooler climates. However, air conditioners might still experience high-demand for locations near the equator.
• Residential and commercial property developers incorporating ultra-white paint into building designs, enhancing energy efficiency and reducing reliance on artificial cooling systems.
• Paint manufacturers facing shifts in supply chain dynamics, as demand for ultra-white paint ingredients surges, impacting global raw material markets.
• Urban planners integrating ultra-white paint in public infrastructure projects to mitigate heat island effects, leading to improved urban climate conditions.

Questions to consider

• How else can ultra-white paint be used beyond building infrastructures and transportation? 
• How else can the ultra-white paint encourage researchers to develop materials that combat global warming?