Graduate student Corey Hewitt works with a sample of thermoelectric fabric in the Nanotechnology lab. |
When graduate student Corey Hewitt (Ph.D. ’13) touches a two-inch square of black fabric, a meter goes berserk.
Simply
by touching a small piece of Power Felt—a promising new thermoelectric
device developed by team of researchers in the Center for Nanotechnology
and Molecular Materials—he has converted his body heat into an
electrical current.
Comprised
of tiny carbon nanotubes locked up in flexible plastic fibers and made
to feel like fabric, Power Felt uses temperature differences—room
temperature versus body temperature, for instance—to create a charge.
“We
waste a lot of energy in the form of heat. For example, recapturing a
car’s energy waste could help improve fuel mileage and power the radio,
air conditioning or navigation system,” Hewitt says. “Generally
thermoelectrics are an underdeveloped technology for harvesting energy,
yet there is so much opportunity.”
The research appears in the current issue of Nano Letters, a leading journal in nanotechnology.
Potential
uses for Power Felt include lining automobile seats to boost battery
power and service electrical needs, insulating pipes or collecting heat
under roof tiles to lower gas or electric bills, lining clothing or
sports equipment to monitor performance, or wrapping IV or wound sites
to better track patients’ medical needs.
“Imagine
it in an emergency kit, wrapped around a flashlight, powering a weather
radio, charging a prepaid cell phone,” says David Carroll, director of
the Center for Nanotechnology and Molecular Materials. “Literally, just
by sitting on your phone, Power Felt could provide relief during power
outages or accidents.”
Cost
has prevented thermoelectrics from being used more widely in consumer
products. Standard thermoelectric devices use a much more efficient
compound called bismuth telluride to turn heat into power in products
including mobile refrigerators and CPU coolers, but it can cost $1,000
per kilogram. Like silicon, researchers liken its affordability to
demand in volume and think someday Power Felt would cost only $1 to add
to a cell phone cover.
Currently Hewitt is evaluating several ways to add more nanotube layers and make them even thinner to boost the power output.
Although
there’s more work to do before Power Felt is ready for market, he says,
“I imagine being able to make a jacket with a completely thermoelectric
inside liner that gathers warmth from body heat, while the exterior
remains cold from the outside temperature. If the Power Felt is
efficient enough, you could potentially power an iPod, which would be
great for distance runners. It’s pretty cool to think about, and it’s
definitely within reach.”
Currently Wake Forest is in talks with investors to produce Power Felt commercially.
Multilayered Carbon Nanotube/Polymer Composite Based Thermoelectric Fabrics
