No more thermostats? Color-changing coating inspired by chameleons could revolutionize building construction

WASHINGTON — Scientists have developed a new, cost-effective coating that can adjust the temperature of buildings without using additional energy. Inspired by a desert-dwelling chameleon, this energy-efficient solution could be a game-changer for future building materials.

Traditional heating and cooling systems are notoriously energy-intensive and often rely on fossil fuels. In search of greener alternatives, researchers at the Harbin Institute of Technology in China turned to nature for inspiration.

Many desert-dwelling species have evolved unique adaptations enabling them to endure the extreme and rapidly changing temperatures of their harsh environments, researchers explain in a media release.

For instance, the Namaqua chameleon has the ability to change its color to regulate its body temperature in response to varying environmental conditions. The scientists explain that the chameleon’s adaptation is an example of “passive temperature control,” which could be applied to create more energy-efficient buildings.

color-changing building inspired by chameleons
Inspired by the temperature-adaptive skin color of a chameleon, scientists efficiently combined temperature-adaptive solar absorption and PDRC technology to achieve “warm in winter and cool in summer.” (Credit: Nano Letters)

To develop the coating, the team combined thermochromic microcapsules, specialized microparticles, and binders to create a suspension that could be sprayed or brushed onto metal surfaces. The term “thermochromic” refers to materials that change color in response to temperature changes.

The coating starts to change color from dark to light grey when heated to 68 degrees Fahrenheit. At 86 degrees Fahrenheit, the light-colored film can reflect up to 93 percent of solar radiation. Researchers say the material remained undamaged even when exposed to temperatures exceeding 175 degrees Fahrenheit for a whole day.

The team compared the new material with three conventional options — regular white paint, a passive radiative cooling paint, and blue steel tiles — in outdoor tests on small, doghouse-sized buildings over all four seasons. In the summer, the new coating was significantly cooler than white paint and steel tiles. In the winter, it was slightly warmer than the passive radiative cooling system. During spring and fall, the coating was the only system capable of adapting to fluctuating temperature changes throughout the day.

The findings indicate that this new technology could save a considerable amount of energy in regions that experience multiple seasons. Moreover, the material is cheap and easy to manufacture.

Scientists emphasize that during the transitional seasons of spring and fall, the innovative coating was unique in its ability to adapt to the broad swings in temperature, seamlessly transitioning between heating and cooling throughout the day.

The study is published in the journal Nano Letters.

South West News Service writer Stephen Beech contributed to this report.

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