Nanotechnology fabric converts heat to power

Power Felt
Power Felt using technology at a nanoscopic scale

The Center for Nanotechnology and Molecular Materials at Wake Forest University has developed a new material they call Power Felt. The fabric can convert body heat into an electrical current. It’s made of carbon nanotubes held within plastic fibers and the material has the same look and feel of felt, a material well known for keeping in the heat.

When held close to a warm body or other heat source the Power Felt take advantage of temperature differences and create a charge. That means power can be generated just by insulating something. It can be used to charge a mp3 player or a smartphone, but also for something far more interesting. If used to insulate pipes or buildings you could theoretically generate a charge while you turn on your taps, or just being at home.

“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 and head of the team leading this research. “Literally, just by sitting on your phone, Power Felt could provide relief during power outages or accidents.”

Corey Hewitt with Power Felt
Graduate student Corey Hewitt Corey Hewitt holds a piece of Power Felt.

“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 in a press release. “Generally thermoelectrics are an underdeveloped technology for harvesting energy, yet there is so much opportunity.”

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 cell phone cover.

Currently 72 stacked layers in the fabric 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. While cost has been preventing this type of technology to grow big so far, this isn’t stopping the researchers from seeking out investors for commercial production.

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