New nanotechnology converts heat into power when it's needed most

Feb 22, 2012

Never get stranded with a dead cell phone again. A promising new technology called Power Felt, a thermoelectric device that converts body heat into an electrical current, soon could create enough juice to make another call simply by touching it.

Developed by researchers in the Center for and Molecular Materials at Wake Forest University, Felt is comprised of tiny carbon nanotubes locked up in flexible and made to feel like fabric. The technology uses temperature differences – room temperature versus body temperature, for instance – to create a charge.

Their research appears in the current issue of Nano Letters, a leading journal in nanotechnology.

"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," says researcher and Wake Forest graduate student Corey Hewitt. "Generally thermoelectrics are an underdeveloped technology for harvesting energy, yet there is so much opportunity."

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," said David Carroll, director of the Center for Nanotechnology and Molecular Materials. "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 researchers say it can cost $1,000 per kilogram. Like silicon, they liken Power Felt's affordability to demand in volume and think someday it could cost only $1 to add to a cover.

Currently, 72 stacked layers in the yield about 140 nanowatts of power. The team 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, Hewitt says, "I imagine being able to make a jacket with a completely thermoelectric inside liner that gathers warmth from , 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 definitely within reach."

Wake Forest is in talks with investors to produce Power Felt commercially.

Explore further: Moving silicon atoms in graphene with atomic precision

More information: For more information on Power Felt and thermoelectrics research at Wake Forest, go to www.wfu.edu/~carroldl/Thermoelectrics.html

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Tomator
2.5 / 5 (2) Feb 22, 2012
Generally promising, but those 140 nanowatts of power is to be got from, well, square milimeter or square inch? With 1K temperature difference between both material sides? How much energy can the fabric recover while radiating out 1 watt through it?
MR166
3.9 / 5 (7) Feb 22, 2012
"Potential uses for Power Felt include lining automobile seats to boost battery power and service electrical needs......."

Physorg should stop hiring crack heads to write articles. With so much heat in the engine bay of a vehicle why would you try to recover heat from car seats? If it could cool seats it could be useful but it still need to radiate that heat into the rest of the car.
MR166
3 / 5 (4) Feb 22, 2012
I suppose it is wrong to blame Physorg for the ignorance displayed in this article. Wake Forrest should hang it's head in shame for the stupidity this article represents. The invention could be fantastic but the author does not have the slightest idea what the real uses for the product might be. 140 nanowatts wow, fireflies in a jar could produce more power than that if you put a solar cell in with them.
hyongx
5 / 5 (2) Feb 22, 2012
"Potential uses for Power Felt include lining automobile seats to boost battery power and service electrical needs......."

Physorg should stop hiring crack heads to write articles. With so much heat in the engine bay of a vehicle why would you try to recover heat from car seats? If it could cool seats it could be useful but it still need to radiate that heat into the rest of the car.

I wish I could give this ten stars.
Yeah, why would you try and collect heat from car seats when you could put a layer, for example, under the hood of the car, or below the engine, where the thermal gradient was between the engine (hottest part of the car) and the external air (cooling medium)? durrrrrr.
jscroft
3.7 / 5 (3) Feb 22, 2012
I'd line the catalytic converter with the stuff.
Deesky
3 / 5 (4) Feb 22, 2012
I wish I could give this ten stars.
Yeah, why would you try and collect heat from car seats when you could put a layer, for example, under the hood of the car, or below the engine, where the thermal gradient was between the engine (hottest part of the car) and the external air (cooling medium)? durrrrrr.

I agree, it does sound daft, but perhaps the reason is that the material may not be able to tolerate very high temperatures as generated by the engine and exhaust system?
gwrede
1 / 5 (1) Feb 23, 2012
Yeah, why would you try and collect heat from car seats when you could put a layer, for example, under the hood of the car
I agree, it does sound daft, but perhaps the reason is
It is daft. The energy available from the driver's butt is tiny compared to the vast amounts the radiator is trying to expel.

If the material is not heat tolerant, which I very much doubt since few plastics have a problem with boiling water, this is an easy engineering problem to fix, anyway.

So, we're back to the author being entirely uneducated in physics. She probably works in the PR department of either WFU or the startup company.

I DO WISH PhysOrg would hire people to weed out the most obvious marketing, the most obvious stupidities, and badly written articles.
MR166
2.3 / 5 (3) Feb 23, 2012
The scary part of this article is that it was released by Wake Forrest. Now they are not supposed to be on the same level as some community college in the Ozarks. In fact, my high school physics teacher would have given this paper an F minus if there is such a thing.
A_Paradox
not rated yet Feb 27, 2012
I agree with the crowd, as far as trying to use the car driver's body heat goes. Duh! But I wondered whether maybe someone had their wires crossed, so to speak. I mean perhaps the original thought had been that running the power felt in reverse, ie supplying a voltage _to_ the cloth could maybe cool the driver in summer with the voltage one way and warm the driver in winter by applying voltage with opposite polarity.

And where does it say the reporter is a woman?