What Do Zebras and Termites Have in Common? Green Ideas for Innovation in Air Conditioning

Very little on the surface, but if you’re looking for ideas to live in a temperate climate, without the cost or environmental impact of air conditioning, they provide some cool answers. There have been many improvements in the heating and air conditioning industry, specifically reducing and eliminating the use of ozone damaging chlorofluorocarbons (CFCs). Even before the Montreal Protocol or the Kyoto Agreement, this industry voluntarily began to improve their products. The main improvement is the replacement of CFCs with Hydrofluorocarbons (HFCs) because of their safety, performance, and lack of effect on ozone depletion. In other words, they have less global warming potential.

Kudos to them. They’re going in the right direction. But here’s a greener approach: Instead of adding machinery to cool air, re-design the architecture so that it cools itself. Enter the zebra. The black and white stripes, according to biologist Benyus, create variations in air temperature just above the skin’s surface to create an air current and natural cooling system that surrounds the animal.

Let’s run with this idea. Could we paint stripes on buildings to achieve the same effect? Treat this as a seed of an idea before you pitch it. Before you envision an optical nightmare of numerous black and white striped buildings existing everywhere, open up your mind to considering similar ideas where a removable skin could be applied only in the hottest months. The skin could have other more eye-pleasing shapes of differing colors. Or perhaps movable reflectors that can be added to surfaces where the solar energy can be re-directed to darker areas that need light while reflecting heat away from hotter areas.

If you don’t like this direction in thinking, look toward termites. They are natural farmers that farm their own food source of fungus. The challenge is that some termites live in 100-degree weather yet their fungus must be kept at exactly 87 degrees. It’s not a problem for the termites though. Their towers are built to contain a series of heating and cooling vents that suck in air at the lowest part of the termite mound, down into their muddy wall enclosures and then back up to the peak. They constantly dig new vents and plug up the old ones throughout the day to regulate temperature.

At first glance, that isn’t an appealing idea because of all of the effort involved every day. But if you take it as only the seed of an idea, there’s a lot to work with. Architect Mick Pearce did exactly that. He designed the Eastgate Shopping Center in Harare, Zimbabwe, using both these ideas in a passive cooling system. This system works by storing heat in the day and venting it at night as temperatures drop. At the start of day, the building is cool. As the day gets warmer, and machines, people and the sun generate heat, the heat is absorbed by a fabric in the building, so that the temperature inside increases but not greatly.
In the evening, the temperatures outside drop and the warm internal air is vented through chimneys and fans, drawing in denser cool air at the bottom of the building. At night this process continues, the cold air flow in through cavities in the floor slabs until the building’s fabric has reached the ideal temperature to start the next day.

Eastgate uses only 10% of the energy needed saving millions each year and is completely environmentally friendly.

See what happens when you keep an open mind?


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