November 27, 2008

Biomimicry captures imagination of green builders

SAUL CHERNOS

correspondent

Wind turbine blades modelled on whale flippers. Solar cells that resemble leaves on a tree. Apartment storeys that whirl with the wind. Condo towers enveloped by forest.

Whimsical flights of fancy, or down-to-earth practical?

Buildings that imitate nature aren’t entirely new. Our ancestors lived in caves, and igloos and mud huts have passed the test of time in certain geographies. Still, as we struggle to downsize our carbon footprint in the face of warnings about climate change, biomimicry is capturing the imagination of more than a few green builders.

Christopher Sweetnam-Holmes of EcoCité Developments offers up some of his favourite buildings.

Sweetnam-Holmes borrows a definition Janine Benyus coined in her 1997 book, Biomimicry — a science that studies nature’s best ideas and then imitates these designs and processes to solve human problems.

“It’s as simple a bird and an airplane,” he explained during a recent green building event in Toronto.

“But, it goes deeper than that. A classic example is Velcro, hook-and-loop fasteners modelled on the burrs a Swiss engineer’s dog picked up during a walk in the woods.”

While humans fight against nature and physically manipulate materials to achieve a desired outcome, this requires the input of energy and materials and often results in toxic outputs. Nature, on the other hand, represents billions of years of evolutionary development, Sweetnam-Holmes said. “It uses only the energy it needs, it doesn’t waste, it rewards co-operation, it curbs excesses from within, and it values diversity and local expertise. Form fits function.”

Sweetnam-Holmes pointed to some real-world examples, including one that anyone who watched the Olympics should recognise – the Bird’s Nest in Beijing. “A bird assembles small pieces and builds a strong structure,” he says.

The Adam Joseph Lewis Center for Environmental Studies at Oberlin College in Ohio uses wetlands to treat sewage, gardens to produce food, and solar systems to generate all the electricity the building needs. “It’s a great example of a systems approach,” Sweetnam-Holmes said. “It’s fully integrated. Literally, all the circuits of this building are closed. Nature recycles everything.”

In Dubai, the cylindrical Burj al-Taqa skyscraper — currently under construction — is designed to expose as little surface to the sun as possible. Inspired by the Hymenocallis, a flower widespread in the region, the tower will include more than 160,000 square feet of solar cells and a rooftop wind tower. “Each floor will be able to rotate independently, as the sun rises through the sky,” Sweetnam-Holmes said.

Researchers are working on other projects. Sweetnam-Holmes said wind turbine blades have been improved by modelling them on whale flippers. In Japan, the National Institute of Advanced Industrial Science and Technology has developed small solar cells based on leaves. “If one of them gets shaded it doesn’t influence the whole system, whereas if you get five percent shading in a traditional photovoltaic solar panel production declines significantly.”

In Milan, plans are underway for Bosco Verticale, or vertical forest – two 20-storey residential towers whose façades are to be completely surrounded and covered by trees, shrubs and bushes. “Depending on the face of the building, there will be a different kind of forest,” Sweetnam-Holmes explained.

Sweetnam-Holmes – who integrates natural features into his own projects in Ottawa and Montreal on an admittedly modest scale – said he’s convinced biomimicry has a future in building design. “Green buildings are good, but they’re only halfway between what we’re building now and where we need to be. Nature, imaginative by necessity, has already solved the problems we’re struggling with.”

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