How new nanotechnology converts heat into power
What if you could simply touch your cell phone to recharge it?
What if you could simply touch your cell phone to recharge it?
Researchers at the Centre for Nanotechnology and Molecular Materials at Wake Forest have developed a new technology referred to as Power Felt. It consists of a thermoelectric device which can generate an electric current by using nothing else but body heat.
Power Felt consists of microscopic carbon nano-tubes which have been embedded in flexible plastic fibres. The end result feels quite similar to most synthetic fabrics. The system utilises the difference in temperature between your body temperature and the temperature of your environment to create an electrical charge.
Corey Hewitt, a graduate student at Wake Forest, says: “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.”
He added that, while there were huge opportunities hidden in the field of thermoelectrics, it still remained a relatively underdeveloped technology.
Potential uses of the new technology include using Power Felt to cover motor car seats which will then generate electricity which can boost battery power. Another possible application is to place it under roof tiles to lower electricity and gas bills.
The director of the Centre for Nanotechnology and Molecular Materials, David Carroll, said: “Imagine it in an emergency kit, wrapped around a flashlight, powering a weather radio, charging a prepaid cell phone; Power Felt could also provide relief during power outages or accidents.”
One of the major hurdles that prevented the widespread use of thermoelectrics for everyday devices has been the high cost of these applications.
Ordinary thermoelectric devices utilise a compound by the name of bismuth telluride to convert heat into power in products such as CPU coolers and mobile refrigerators. The cost of this material can be as high as $1,000 per kg.
This is where Power Felt could revolutionise the industry one day: once it reaches the point of mass production it could cost as little as $1 for a thermoelectric cell phone cover made from Power Felt.
At present about 140 nanowatts of power can be generated by using stacked layers in the fabric. The team is researching a number of different ways to make these nanotube layers even thinner so they can add more of them to increase the power output.
Although it’s still a long way before Power Felt will appear on supermarket shelves, researchers are confident about its ultimate success. They already envisage jackets with Power Felt linings to preserve body heat and even iPods running solely on the power generated by the owner’s body heat.
The university is currently involved in discussions with investors with the aim of manufacturing Power Felt commercially.
