Converting energy at the nanoscale to reduce energy waste

Posted on Tuesday, March 23, 2021

Converting energy at the nanoscale to reduce energy waste

Video demonstrating sub-100 distance control between parallel surfaces for near-field radiative heat transfer experiments. The whole frame is less than 0.05 mm wide.

Video demonstrating sub-100 distance control between parallel surfaces for near-field radiative heat transfer experiments. The whole frame is less than 0.05 mm wide. Photo credit : St-Gelais Lab

Of all the energy consumed in the world, over 50% of it is wasted as heat in the surrounding environment, with less than 0.5% of this heat being converted back into electrical power. Professor Raphael St-Gelais and his team are working to create a solution that would recycle this heat into electricity using a portable conversion module, which could be mounted directly onto any hot surface.

Large scale solutions do exist at the moment, though their portability is minimal, if even possible at all. Their smaller counterparts, such as thermoelectric generators, are typically very costly and low in efficiency. St-Gelais hopes to change this using a novel-yet-promising approach called Near-Field Thermophotovoltaics, a theory that has been highly researched but never demonstrated.

The basis is that thermal light emitted by a heat source can be converted into electrical power. To do so, St-Gelais uses a specially tailored photovoltaic cell, which is placed extremely close to the hot material, such that the thermal radiation intensity is enhanced by near-field effects. However, the distance between the cell and the heated material must be nanometric, which is extremely challenging to achieve.

In order to overcome this obstacle, Professor St-Gelais and his team have built micro machines to control the distance and are working towards the first-ever demonstration of this heat-to-energy conversion using an actual photovoltaic cell.

The St-Gelais Lab distinguishes itself by working at the intersection of photonics and optics, micro mechanics and thermal transfer. Their goal? To drastically improve on existing technology and reduce energy waste. Possible applications for this include capturing heat emitted by a car and re-investing into its engine as energy or allowing those in remote locations to generate their own electricity locally.

If you wish to reach out to Professor St-Gelais or learn more about his research, please visit his contact page.

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