New thermo-photovoltaic engine flies drones for days without recharging

A new thermophotovoltaic motor, in some ways futuristic, was created by scientists from the University of Berkeley. According to the same press release on the University’s website, thermal energy could represent the future for all unmanned aircraft applications.

The heat caused by the rays coming from the sun, combined with the light, can be considered as an alternative energy source that could allow drones and other relatively light vehicles, of those without a pilot, to work for days continuously. Beyond the drones, the technology could also be used to feed probes into deep space for centuries. In a more practical context, the same technology could then also be used in a normal home with special generators.

In the study, published in Proceedings of the National Academy of Sciences, the researchers describe the thermo-photovoltaic motor that can be used in particular for drones. The secret of the new solar cells that the same engineers have created does not lie in the greater capacity to absorb photons but to emit them, or rather to reflect them. They then added a highly reflective mirror to the back of each photovoltaic cell.

The same cells can, therefore, create an infrared luminescent photonic gas, a phenomenon that does nothing but add more tension, as specified by Eli Yablonovitch, professor of electrical engineering at Berkeley and one of the authors of the study. Such a system can also reflect photons to heat a thermal source, a second possibility of generating electricity.

This additional source has led to unprecedented efficiency so it could allow, for example, a drone to be able to fly for days. The same engineers think they can make the system even more efficient by adding an additional dielectric layer to increase the reflectivity and bring the efficiency to 36%, as reported by Luis M. Pazos, another author of the study.

“Only by increasing the reflectivity will we achieve an efficiency of 36%. But by making other changes to the cell, using proven techniques in the scientific literature, we know that we can achieve an efficiency of 50%,” declares Outόn himself.