Sun, Dec 13, 2009 - Page 8 News List

Nature has answers to problems

By Bruno Walther

two recent editions of the Taipei Times had articles on how green buildings may save energy and resources (“Greening Asia’s buildings” Nov. 28, page 9, and “Living in a greener Big Apple,” Nov. 29, page 9). However, while the articles reported on some interesting developments and made a good economic argument for efficient buildings, descriptions of new ideas coming from science and engineering were a bit thin on the ground (this being a rather nice pun for a lack of insulation).

As buildings account for about one-third of global energy use, improving their resource and energy performance is critical to achieve sustainability. I teach all my students that we should imitate nature’s solutions to get us out of the environmental mess. For example, nature recycles 100 percent of all materials and uses only solar energy. Imitating that would go a long way toward solving many environmental problems.

Forward-looking architects, designers and engineers have started doing exactly that, and they call it biomimicry — mimicking biological methods and systems to enhance the design of engineering systems and modern technology (a wonderful introduction to this emerging field is Janine Benyus’ book Biomimicry).

Mother Nature has had billions of years to evolve highly optimized and efficient solutions to its own engineering and design difficulties. Hence, nature is teeming with solutions to our environmental problems. Here’s an amazing example: Termites living in the African savanna somehow manage to keep their buildings, called mounds, at a constant temperature while outside temperatures fluctuate wildly. How do they do it?

They constantly open and close a series of heating and cooling vents throughout the mound over the course of the day, and this ingenious system of air current regulation has now been imitated in several modern buildings, reducing energy costs by up to 90 percent (search Internet for “termites Eastgate” and “Portcullis House”).

But so-called bionic buildings go much further: They use intelligent design to reduce the use of materials (think the Eiffel tower and its skeleton-like structure) or to respond smartly to a changing environment (think Taipei 101 and its wind and earthquake damper).

Bionic buildings, like the termite mounds, react to outside heat, cold or wind by changing internal air currents, shading or opening windows, or recycling water continuously through internal gardens that clean the water, stabilize internal temperature and improve air quality (search Internet for “bionic building”).

In the future, truly responsive buildings would gather all residual compressive loads into a single mast and then respond to changes in internal and external forces by adaptively changing their state of prestress, giving extreme lightweight stability (www.bath.ac.uk/mech-eng/biomimetics/).

Further ideas include making tougher cement with less energy (search Internet for “Roman concrete”) and self-cleaning walls and windows (www.treehugger.com/files/2005/09/sto_lotusan_bio.php).

However, unused building surfaces are actually a wasted resource and should instead be covered either with solar panels or with plants.

So-called green roofs have many benefits: They decrease storm water and urban heat, improve the building’s insulation, water and air quality, and provide habitat for plants and animals and a place for people to relax.

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