Waste heat could be a valuable source of energy – if only we could find a way to capture it efficiently. Now two Duke University researchers have a plan to do just that. They have developed a new thermophotovoltaic device that harvests energy from waste heat by capturing infrared wavelengths.
Thermophotovoltaics could potentially change the way we generate energy in the future. Regular solar cells simply absorb visible light, but the technology from the Duke University team absorbs infrared light. The device is made with a metamaterial, or a synthetic material containing properties not accessible in natural materials, that enables it to efficiently take in and emit infrared light.
The team’s minuscule device is an “8 x 8 array of individually controllable pixels,” according to The Optical Society; each pixel is a mere 120 by 120 microns. Controlling those pixels with microelectromechanical systems, the researchers are able to change infrared emission properties rapidly in each pixel. The device can display patterns of infrared light at speeds of 100,000 times per second.
In a statement, Duke University engineer Willie Padilla said, “Because the infrared energy emission, or intensity, is controllable, this new infrared emitter could provide a tailored way to collect and use energy from heat. There is a great deal of interest in utilizing waste heat, and our technology could improve this process.”
The device’s materials don’t even change temperature as they harness heat, so it can be utilized at room temperature. Many other methods of variable infrared emission need high temperatures to operate; some natural materials have been able to do the job at room temperature but are “limited to narrow infrared spectral ranges,” according to The Optical Society.
Their journal Optica recently published their research online.