Energy Harvesting Devices: a New Power Source

Electromagnetic radiation surrounds us at all times in the form of microwaves for phone signals, WiFi, satellite signals and more. The means to harvest power from this radiation would represent a huge resource. Such a power-harvesting device has been developed by a research team led by Steven Cummer at Duke University’s Pratt School of Engineering. They have engineered a system that harnesses microwaves, converting them into electrical energy that can recharge small electronic devices.

Metamaterials, artificial materials designed to have properties often not found in nature, can be engineered in order to harness different types of wave energies and convert them to useful functions, in this case, electrical energy. Made from inexpensive materials, Cummer’s fiberglass and copper energy conductor converts microwave energy into direct current voltage. The basic system is self-contained and additive, meaning it can be extended to boost energy harvesting capabilities. A single metamaterial cell can power an LED, while the device made by Cummer and his team is composed of 5 cells. Efficiency in this new design is around 37%, comparable with that achieved from solar cells. The generated 7.3V of electricity is sufficient to recharge a mobile phone battery, and the potential for enhancing the system to generate more power is clear.

The practical applications for this technology are significant. The ability to wirelessly harvest stray microwaves means that similar devices could be set within mobile phones to recharge the battery when the phone is not in use, harnessing energy from a phone mast in place of conventional power sources. They might also be fitted in rooms to utilise Wi-Fi signal that would be lost at present. There is also the possibility of using banks of these cells to generate much more power for countless other uses.

Read more at: http://www.pratt.duke.edu/news/wireless-device-converts-lost-energy-electric-power