'Power Felt' Transforms Heat Into Electricity
Graduate student Corey Hewitt holds a piece of Power Felt, a new cloth-like material that converts heat into electricity.
CREDIT: Wake Forest University
A new, cloth-like material that transforms body heat into electricity someday could allow you to squeeze one last call from your dead cell phone simply by rubbing it.
The material, which its developers at Wake Forest University are calling Power Felt, is composed of carbon nanotubes mixed with flexible plastic fibers that mimic the feel of fabric. Power Felt uses temperature differences – say, room temperature versus body temperature – 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,” said Corey Hewitt, a graduate student at the university's Center for Nanotechnology and Molecular Materials.
The fabric has 72 stacked layers that yield about 140 nanowatts. The team is evaluating several ways to add more nanotube layers and make them even thinner to boost the power output.
Hewitt and his team envision Power Felt being used as a lining for automobile seats or roof tiles to boost battery power, as pipe insulation, as a covering for IV or wound sites to track patients' medical needs, or as lining for clothing or sports equipment to monitor performance.
“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," Hewitt said.
"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.”
Power Felt also could be useful in emergency situations such as an accident or power outage.
“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 in Winston-Salem, N.C.
Power Felt would be expensive to produce at first, but the team thinks if the demand is there and it can be produced in enough volume, adding the power-generating material to a cell phone cover could someday cost as little as $1.
The team detailed its Power Felt technology in the current issue of the journal Nano Letters.