Electronic devices that convert ‘Waste Heat’ into electricity soon to become reality

Researchers use quantum mechanical effect to convert waste heat into electricity

In an attempt to find a novel way of generating electricity, researchers have led to a breakthrough that will enable future electronic devices to generate electricity from heat. A team of researchers previously showed that they can use the quantum mechanical effect to convert heat into electricity which might solve the energy crisis, especially portable devices like smartphones.

In a recent study, the same team of researchers from the Ohio State University in the US has finally found a way using magnetism to transform heat energy into electrical energy. Study authors successfully amplified the voltage output 10 times or more by using magnetism on a composite of nickel and platinum. They used thick layer to material which resembled like future electronic devices.

Scientists explained that many engines around us including cars and motors produce waste heat during their normal operations. By using solid-state thermoelectrics aims, researchers are aiming to capture this waste heat and use it for our benefit which will further increase the energy utilisation and efficiency.

Lead researcher Stephen Boona, a postdoctoral researcher at Ohio State explained that nearly 50 percent of the heat energy produced in an operation is lost into atmosphere and we can recover some of the waste energy using Solid-state thermoelectrics. “These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also too expensive and not quite efficient enough to warrant widespread use. We’re working to change that,” said Boona.

Previously back in 2012, a team of researchers showed the way to generate electricity using quantum mechanical effect when they amplified the voltage output of thin films made from exotic nano-structured materials from a few microvolts to a few millivolts.

In the latest study, researchers used nickel with sprinkling of platinum and boosted voltage to a much higher extent (over 1000 times than previous studies). This time, study authors used more thicker pieces of material and found success.

“Basically, classical thermodynamics covers steam engines that use steam as a working fluid, or jet engines or car engines that use air as a working fluid. Thermoelectrics use electrons as the working fluid. And in this work, we’re using quanta of magnetization, or ‘magnons,’ as a working fluid,” Heremans said.

Scientists have conducted mangnon-based thermodynamics research till now but all of them used few atoms thick material that were able to produce very small voltages.

In the 2012 paper, his team described hitting electrons with magnons to push them through thermoelectric materials. In the current Nature Communications paper, they’ve shown that the same technique can be used in bulk pieces of composite materials to further improve waste heat recovery.

This time researchers distributed a very small amount of platinum nanoparticles randomly throughout a magnetic material (nickel) instead of pplying a thin film of platinum on top of a magnetic material as they might have done before. The resulting composite produced enhanced voltage output due to the spin Seebeck effect. This means that for a given amount of heat, the composite material generated more electrical power than either material could on its own. Since the entire piece of composite is electrically conducting, other electrical components can draw the voltage from it with increased efficiency compared to a film.

While the composite is not yet part of a real-world device, Heremans is confident the proof-of-principle established by this study will inspire further research that may lead to applications for common waste heat generators, including car and jet engines. The idea is very general, he added, and can be applied to a variety of material combinations, enabling entirely new approaches that don’t require expensive metals like platinum or delicate processing procedures like thin-film growth.

The study appeared in the journal Nature Communications.

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