Geckos, Human Skin and Whale Fins: How Biomimicry Inspires Green Building

The terms biomimicry and biomimetics come from the Greek words "bios", meaning life, and "mimesis", meaning to imitate.

Nature uses highly efficient natural selection and evolution to develop the best and most effective techniques for achieving certain goals... Indeed, examples of biomimicry can be found in automobile design, weapons development and building materials.

Shouldn't designers turn to nature for inspiration when planning high performance building projects?

Here are three examples of energy efficiency inspired by nature.

Window Insulation and Human Skin

Professor Ben Hatton of the University of Toronto had an “Aha!” moment when he applied the way living organisms have evolved to control internal body temperatures to the problem of energy leaks from windows in buildings (buildings lose as much as 40% of their energy through their windows).

Hatton and his colleagues at Harvard University considered that living organisms dilate their blood vessels to increase blood flow close to the surface of their skin.

Humans do this in order to maximize convective heat transfer... conversely we constrict our blood vessels to limit blood flow when exposed to cold.

According to Biomimicry News, the team applied this biological concept and developed a novel process to cut down on heat loss during the winter and keep buildings cool during the summer.

Their "bio-inspired approach to thermal control for cooling (or heating) building window surfaces" calls for attaching optically clear, flexible elastomer sheets, bonded to regular glass window panes.

The transparent blood-vessel-like layer is capable of 7-9 degrees of additional cooling.

Gecko Feet and Low Emitting Adhesives

An invention developed by a group of polymer scientists and biologists at the University of Massachusetts Amherst is called “Geckskin.”

Geckskin™ is a new attach-and-release material that replicates the feet of the gecko. Using van der Waals forces, the Geckskin fabric technology, made from fabrics such as nylon, Kevlar, or carbon fiber peels away easily on any surface, leaves no residue, and can hold up to 700 lbs with only minimal contact.

This opens up the potential for many adhesive applications that would obviate the need for high VOC emitting chemicals, thereby potentially improving the quality of green building indoor environments.

According to UMass Amherst, Geckskin won Fabriclink's top 2013-2014 awards for textile innovations.

Geckskin combines two components, an elastomer (rubber-like materials) and a fabric, which creates both a soft and stiff material. These textile elements replicate the footpad of the gecko, where a tendon on the gecko's toes integrates with its skin, and is directly connected to a soft and compliant pad.

Geckskin employs both a synthetic 'tendon' and 'skin', which are interwoven in much the same way. Geckskin is anticipated to impact a broad range of applications including apparel, household hanging, and manufacturing assembly processes.

The resulting fabric can hold up to 700 pounds with only 16 inches square of material. The video below explores different biomimetic applications for the science behind gecko feet.

Whale Fins and Turbine Blades

It might be surprising that a whale’s fin that is used in water can be an effective model for wind turbines.

A whale’s fin has large, irregular bumps called tubercules across its leading edges. Water passing through a humpback whale’s tubercules maintains even channels of fast-moving water, whereas smooth flippers break up into myriad turbulent vortices as they cross the flipper. The tubercules allow humpbacks to hold a firmer grip on the water, allowing them to turn sharp corners.

Wind turbines modeled after humpback whale fins demonstrate aerodynamic improvements allowing for an 8% improvement in lift, a 32% reduction in drag, and a 40% increase in angle of attack. In this case, the use of biomimicry increases the efficiency of wind turbines, making wind energy an even more effective form of renewable energy.

Natural selection works through trial and error over generations. The techniques developed in nature are proven as the most efficient. By mimicking nature, there is less need for research and development, testing, and fewer instances of error in order to get the best solution more cheaply and quickly.