Researchers have created a new type of cement tile inspired by elephant skin that could help buildings stay cooler without relying on air conditioning.
The simple, low-cost material captures water and slowly releases it through evaporation, naturally lowering surface temperatures and reducing the need for energy-intensive cooling.
The research, led by scientists at the University of Pennsylvania and published in Advanced Materials, takes inspiration from an unexpected source.
Although elephants live in some of the hottest environments on Earth, they do not sweat like humans. Instead, their deeply wrinkled skin contains networks of tiny cracks that trap water after the animals spray themselves.
As the water slowly evaporates, it carries away heat and helps keep the elephants cool.
The researchers wondered whether buildings could use the same natural cooling strategy.
Modern buildings consume enormous amounts of energy for heating and cooling. In the United States alone, buildings account for about 40% of primary energy use, with nearly half of that going toward heating, cooling and ventilation. Traditional air conditioners also release heat outdoors, making cities even warmer during heatwaves.
The new cement tiles work differently. Rather than cooling indoor air with electricity, they cool the building’s outer surface by storing water and allowing it to evaporate slowly over many hours.
To create the material, the team mixed ordinary Portland cement with diatomaceous earth, a naturally porous material made from the fossilized remains of tiny algae. After the mixture was formed into thin tiles, it was carefully dried so that a controlled pattern of tiny cracks developed across the surface.
Normally, cracks in concrete are seen as signs of damage. In this case, however, the researchers deliberately engineered them to improve performance.
The microscopic pores inside the material quickly soak up water, while the crack network spreads that water evenly across the surface. Instead of droplets running off immediately, the water is absorbed within milliseconds and moves through the interconnected channels, even across sloping surfaces. The special honeycomb-like crack pattern forces the water to travel sideways instead of simply draining away, helping keep the surface wet for much longer.
As the stored water gradually evaporates, it removes heat from the tiles in the same way that sweat cools human skin. In laboratory tests, the cooling effect lasted for up to 20 hours after watering.
The results were impressive. Under infrared heating, the temperature beneath the new tiles remained at about 32°C (89.6°F). By comparison, conventional cracked stucco reached around 42°C (107.6°F), while standard stucco without cracks climbed to about 52°C (125.6°F). Overall, the new material lowered surface temperatures by roughly 6 to 11°C (10 to 20°F) compared with traditional building finishes.
The researchers believe the technology could be practical as well as affordable. The cement mixture can be sprayed onto large building panels using existing construction equipment, making it suitable for large-scale installation without expensive manufacturing methods.
Looking ahead, the team hopes to combine the cooling tiles with smart watering systems that use weather forecasts to apply only the amount of water needed before periods of extreme heat. Such systems could maximize cooling while conserving water.
As heatwaves become more frequent and severe around the world, the researchers believe that working with natural processes rather than fighting them could help create cooler, more energy-efficient and more comfortable cities.
The study was published in Advanced Materials.
