Optofludics: There’s one we haven’t seen before on the virtual pages of EarthTechling. But in the October issue of Nature Photonics, Demetri Psaltis of Ecole Polytechnique Fédérale de Lausanne (EPFL) and two co-authors say this discipline, which brings together light and liquid in a unique way, might just be able to unlock new efficiencies in energy production.
“By directing the light and concentrating where it can be most efficiently used, we could greatly increase the efficiency of already existing energy producing systems, such as biofuel reactors and solar cells, as well as innovate entirely new forms of energy production” Psaltis says, according to EPFL’s account of his Nature Photonics piece.
A key point to understand is that optofluidics as Psaltis approaches it doesn’t just mean light + water, which we already see in thermal solar systems and methane biogas production. Instead, he combines optics with microfluidics – the microscopic delivery of fluids through extremely small channels or tubes using nanotechnology.
To bring the concept to life, EPFL gives an example of how optofluidics could light a building with startling efficiency: “An optofluidic solar lighting system could capture sunlight from a roof using a light concentrating system that follows the sun’s path by changing the angle of the water’s refraction, and then distribute the sunlight throughout the building through light pipes or fibre optic cables to the ceilings of office spaces, indoor solar panels, or even microfluidic air filters.”
But what if a cloud passes overhead? “To maintain a constant light source, a system using electrowetting could deviate light from one channel into another both easily and inexpensively.”
According to EPFL, the review by Psaltis and his co-authors in Nature Phontonics “lays out several possibilities for up-scaling optofluidics, such as using optical fibers to transport sunlight into large indoor biofuel reactors with mass-produced nanotubes.” Furthermore, “They point out that the use of smaller spaces could increase power density and reduce operating costs; optofluidics offers flexibility when concentrating and directing sunlight for solar collection and photovoltaic panels; and by increasing surface area, the domain promises to reduce the use of surface catalysts – the most expensive element in many reactors.