Engineers develop a chip that converts lost heat into usable energy

It is estimated that nearly two-thirds of the energy consumed in the United States each year is wasted in heat. Take, for example, car engines, laptops, cell phones, or even refrigerators, which overheat.

Imagine if you could capture the heat that they generate and turn it into more energy.

Mathieu Francoeur, associate professor in mechanical engineering at the University of Utah, discovered a way to produce more electricity from heat than by creating a silicon chip, also called "device", which converts more heat radiation into electricity. Its findings were published in the document A near-field radiation heat transfer device in the latest issue of Nature Nanotechnology.

Researchers have previously determined that there is a theoretical "black body limit" as to the amount of energy that can be produced from a thermal radiation (heat). But Francoeur and his team demonstrated that they could go well beyond the blackbody limit and produce more energy if they created a device using two silicon surfaces very close to each other. The team produced a 5mm chip on 5mm (about the size of an eraser head) of two silicon wafers separated by a nanoscale space of only 100 nanometers in thickness , one thousandth of the thickness of a human hair. While the chip was in the vacuum, they heated one surface and cooled another, which created a heat flow that could generate electricity. The concept of creating energy in this way is not unique, but Francoeur and his team have discovered a way to fit the two silicon surfaces evenly close to each other on a microscopic scale without To touch oneself. The closer they are to each other, the more they can generate electricity.

"Nobody can emit more radiation than the black body limit," he said. "But when you go to the nanoscale, you can."

Francoeur plans in the future to use this technology not only to cool portable devices such as laptops and smartphones, but also to channel this heat into a longer battery life, perhaps up to 50% more. A laptop with a charge of six hours could pass at nine, for example.

Fleas could be used to improve the efficiency of solar panels by increasing the amount of electricity from the heat of the sun or in automobiles to use engine heat to help power the electrical systems. They could also be designed for implantable medical devices, such as a pacemaker, that would not require replaceable batteries.

Another advantage is that such technology can help improve the life of computer processors by keeping them cool and reducing wear, and saving more energy, which would otherwise be used by fans for cool the processors. It could also help improve the environment, Francoeur said.

"You are putting heat back into the system in the form of electricity," he said. "Right now, we're pouring it into the atmosphere, which warms your room, for example, and then you use your air conditioner to cool your room, which wastes more energy."