February 14, 2012

Plastic “Trees” Generate Energy From Wind

Image via creativemachines.cornell.edu There have been many suggestions on how to harness wind to power buildings or just to produce more clean sources of energy to add to the grid. The problem is that many of these technologies are prohibitively expensive, so that the cost of producing the devices is not offset by the amount […]

By: Sherin Wing

Image via creativemachines.cornell.edu

There have been many suggestions on how to harness wind to power buildings or just to produce more clean sources of energy to add to the grid. The problem is that many of these technologies are prohibitively expensive, so that the cost of producing the devices is not offset by the amount of energy they produce.

At the Cornell Creative Machine’s Lab, researchers in Mechanical Engineering are working to address just those issues. They’re investigating “the principles and feasibility” of capturing wind that flows around buildings rather than merely relying on wind turbines which, to date, have offered the only source of wind power. But wind turbines, while effective, have limitations because of their size and location requirements.

The team of researchers from Cornell and from China’s Northwestern Polytechnic University in Xi’an, wanted to create something smaller, more adaptable and ultimately, more flexible. So they designed a device based on a leaf and they called it the “Piezo-Leaf Generator.” It is made of solid piezoelectric materials that, when stressed, in this case by wind, generate electricity. Generally, these materials are rigid such as crystals or ceramics, but this team went for flexibility. The material they chose can respond to the variability of wind and outside ambient conditions. The generated electricity is then stored in either a capacitor or another device.

The first test was to assemble the individual “leaves” into a tree-like configuration. They wanted see if a “tree” would light up their offices. But by itself, the flexible material they chose, Polyvinylidene Fluoride (PVDF) did not generate sufficient power for their needs. Then they attached plastic to the PVDF and the power generated increased by 100 fold. They were onto something. The shape of the “leaves” also influenced the amount of power generated.

The next step is to create a “forest” of these trees to test their efficacy as well as their generative capacity. And, similar to the mobile phone towers designed to resemble trees, these Piezo-Leaf Generators may offer a more urban alternative to wind turbine farms. Though we can’t embed power-generating wind devices within the walls of buildings yet, it seems that we can surround them with power-generating “trees.”

Sherin Wing writes on social issues as well as topics in architecture, urbanism, and design. She is a frequent contributor to Archinect, Architect Magazine and other publications. She is also co-author of The Real Architect’s Handbook. She received her PhD from UCLA. Follow Sherin on Twitter at @xiaying

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