Elephant ears play a crucial role in keep the giant animals cool. Elephants don’t have significant sweat glands. Instead, they rely on their large ears to regulate body temperature. Their ears make up 20% of their body’s surface area. The ears act like a natural air conditioner, making use of a network of blood vessels close to the surface that help dissipate heat when it’s hot and absorb heat when it’s cold.
Researchers at Drexel University have developed a new approach to passive heating and cooling that has the potential to make buildings more energy efficient. The idea, published in the Journal of Building Engineering, embeds the equivalent of a vascular network within cement-based building materials. The network, when filled with paraffin-based material, can help passively regulate the surface temperature of walls, floors, and ceilings.
Building energy demand contributes almost 40% of the production of greenhouse gas from energy use, and about half of building energy use is spent maintaining comfortable temperatures.
The new temperature regulation method puts a grid of paraffin-filled channels in the surface of building concrete. When temperatures drop, the paraffin transitions from liquid to solid and releases heat energy. When ambient temperatures rise, the paraffin absorbs heat energy, producing a cooler surface. This is essentially the same way elephants as well as jack rabbits regulate their temperatures with their large ears.
The Drexel study was a proof-of-concept effort, but the results are promising enough to warrant further work. With additional testing and scaling, it has the potential to make a significant contribution to ongoing efforts to improve the energy efficiency of buildings.
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Photo, posted September 1, 2016, courtesy of Nane Kratzke via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
