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Courtesy of Elias Siores/ Institute for Materials Research and Innovation
The piezoelectric and photovoltaic fiber gets its red color from a final bath in copper, but researcher Elias Siores says the fabric could be dyed any color to suit fashionistas tastes.
New fabric lets you amp up your wardrobe
by Lauren Biron
Feb 18, 2011
Lauren Biron/MEDILL
Researcher Elias Siores says piezoelectric fabric could be used in iPad or cell phone covers, capturing voltage generated by touch and charging the electronics as tech-lovers carry their gadgets around.
Every stride, kick, squat or jiggle contains untapped power in the forced stretching and bending of the cloth. With the energy crisis on everyone’s mind, why aren’t we harvesting all that kinetic energy?
Enter Elias Siores, director of the Institute for Materials Research and Innovation at Bolton University in the United Kingdom.
He’s working on a fiber that machines can weave into a normal cloth that will collect energy from practically any source: sun, rain, wind, sound, tides, and – alert your pants – movement.
The fiber is piezoelectric, a great Scrabble word if there ever was one. Piezoelectric materials generate electricity when they are bent, whether from the pressure of a gust of wind or the impact from a drop of rain.
“When you have vibrations or you shake it or touch it, it produces a charge,” Siores says.
The electrons in the fiber are rearranged, creating a voltage that a battery can capture and, theoretically, use to charge an iPod in your pocket as you walk around.
The fiber also has a photovoltaic coating, allowing it to harvest energy from the sun and act as a flexible solar panel.
You can make bags out of it, Siores says, listing off ideas of where to use it. Jackets. Umbrellas. Army tents. You name it.
“The applications are limited to imagination.”
Siores admits the fiber is not as effective at capturing energy as traditional photovoltaic or ceramic piezoelectric panels. The fabric is just under half as effective at energy capture as a solar panel, but it costs about a sixth of the price.
“What we set up to do, and quite cleverly we achieved it, is reach the low end of the market - not the high end,” Siores says.
An 8-inch square of the fabric can generate about one watt of power, so don’t expect it to power your iPod all at once. But improvements in the technology and widespread applications could add up to a lot of power. Siores says both Saudi Arabia and China have shown interest in the technology, but the United States has been conspicuously absent.
“We would love to reach the U.S.,” he says. “There is a lot of wind in certain areas.”
The fiber itself is a polymer, or plastic, called PVDF, polyvinylidene fluoride. Siores makes it piezoelectric by applying temperature, pressure, and high voltage to orient the molecules as they are continuously extruded from a machine. The fiber then enters various baths that give it a photovoltaic and waterproof coating.
Piezoelectric materials are typically produced in stiff panel form and placed in high traffic areas to gather the energy from footfalls.
“What we have done that no one else has done is make a fiber out of it,” Siores says.
So when will Chicago residents be able to charge their electronics with piezoelectricity? Siores can’t say. “The fibers are ready, provided that someone can mass produce them.”
Elizabeth Redmond, president of POWERleap Inc. based in Ann Arbor, Mich., has a different take on piezoelectricity. She's working to bring down the cost of piezoelectric flooring with economies of scale.
In 2007, she introduced a temporary installation of traditional piezoelectric flooring next to Cloud Gate - better known as "The Bean" - in Millennium Park.
More recently, Redmond developed a permanent system in an exhibition hall in Riyadh, Saudi Arabia. Foot traffic through the entrance will power large LED screens on the walls. Infographics will display how much energy is harvested both in real time and over the course of the exhibition, which is set to open in the spring.
Redmond also works on developing smart floor technology. Embedding small, wireless sensors in the floor panels collects data on occupancy and traffic flow. When connected with a smart building grid, this information can be used to adjust heating and lighting in rooms to save power.
“Our base projections for energy savings are up to 40 percent,” Redmond says.
While Redmond had not heard of Siores’ fiber, she said the technology sounded interesting. Both developers seem to be on the same page.
“The main thing we’re focused on is how to reduce the cost of these devices and bring commercial systems that are actually viable,” Redmond said. “It’s really a matter of scale and intelligent design.”
