The chip made out of two silicon wafers placed at a very small distance is highly effective in increasing the longevity of battery-powered devices
Wastage of energy in the form of heat is a big problem with respect to energy optimisation. Overconsumption often leads to damage of device components and overall system failure.
In order to capture the generated heat and utilise it to meet increased energy requirements, a team of mechanical engineers from the University of Utah, U.S. has developed a way to produce more electricity from heat by creating a silicon chip known as a “device,” that converts more thermal radiation into electricity.
Going beyond the limit
Traditionally, the “blackbody limit” has been referred to as a threshold point for the amount of energy that can be produced from thermal radiation (heat). But the team demonstrated that they can go well beyond this blackbody limit and produce more energy. For this, a 5x5mm chip of two silicon wafers was designed which had a gap of only 100 nanometers thick, or a thousandth the thickness of a human hair. While the chip was in a vacuum, one surface was heated while the other one was cooled. Result was the creation of a heat flux that can generate electricity. The closer the surfaces are to one another, the more electricity can be generated.
Mathieu Francoeur, associate professor – mechanical engineering, University of Utah, said, “Nobody can emit more radiation than the blackbody limit. But when we go to the nanoscale, you can.”
In the future, such technology could be used to not only cool down portable devices like laptops and smartphones but also increase the battery life, up to 50 percent more.
The chips could be used to improve the efficiency of solar panels by increasing the amount of electricity from the sun’s heat radiation or help power the electrical systems in automobiles by taking up heat from the engine. They could also be implanted in medical device such as a pacemaker that would not require replaceable batteries.
Another benefit is the increased longevity of computer processors that saves more energy by relying less on fans to cool the processors.
“You put the heat back into the system as electricity,” said Mathieu Francoeur. “Right now, we’re just dumping it into the atmosphere. It’s heating up your room, for example, and then you use your AC to cool your room, which wastes more energy.”
His findings have been published in the paper, “A Near-Field Radiative Heat Transfer Device,” in the newest issue of Nature Nanotechnology.