Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A guiding light for new directions in energy production

12.09.2011
EPFL Professor and father of optofluidics says the new field could help solve the energy challenge

The science of light and liquids has been intimately entwined since Léon Foucault discovered the speed of light in 1862, when he observed that light travels more slowly in water than in air.

This physical harmony between the two materials is now being harnessed to collect and drive light to where it can be the most useful. October's issue of Nature Photonics focuses on optofluidics, the study of microfluidics—the microscopic delivery of fluids through extremely small channels or tubes—combined with optics.

In a review written by Demetri Psaltis, Dean of EPFL's School of Engineering, he and his co-authors argue that optofluidics is poised to take on one of this century's most important challenges: energy.

"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" explains Psaltis. "EPFL is the world leader in optofluidics, our institution is in a position to develop truly efficient and disruptive energy sources."

Sunlight is already used for energy production besides conventional solar panels. For example, it is used to convert water and carbon dioxide into methane in large industrial biofuel plants. Prisms and mirrors are commonly employed to direct and concentrate sunlight to heat water on the roofs of homes and apartment buildings. These techniques already employ the same principles found in optofluidics—control and manipulation of light and liquid transfer—but often without the precision offered by nano and micro technology.

A futuristic example: Optofluidic solar lighting system
How can we better exploit the light that hits the outside of a building? Imagine sunlight channelled into the building 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. Using sunlight to drive a microfluidic air filter or aliment an indoor solar panel—which would be protected from the elements and last longer—is a novel way to use solar energy to supplement non-renewable resources.

In such a system, it would be essential to deviate from the secondary devices such as air filtrage and solar panels to maintain a comfortable constant light source for ceiling lighting—the flickering of the light source due to a cloud passing over would be intolerable. In order to modulate these different channels to maintain a constant light source, a system using electrowetting could deviate light from one channel into another both easily and inexpensively. A droplet of water sits on the outer surface of light tube. A small current excites the ions in the water, pushing them to the edge of the droplet and expanding it just enough for it to touch the surface of another tube. This expanded droplet then creates a light bridge between the two parallel light tubes, effectively moderating the amount of light streaming through either one.

Up-scaling for industrial use

"The main challenge optofluidics faces in the energy field is to maintain the precision of nano and micro light and fluid manipulation while creating industrial sized installations large enough to satisfy the population's energy demand," explains David Erickson, professor at Cornell University and visiting professor at EPFL. "Much like a super computer is built out of small elements, up-scaling optofluidic technology would follow a similar model—the integration of many liquid chips to create a super-reactor."

Since most reactions in liquid channels happen at the point of contact between the liquid and the catalyst-lined tubes, the efficiency of a system depends on how much surface area is available for reactions to take place. Scaling down the size of the channels to the micro and nano level allows for thousands more channels in the same available space, greatly increasing the overall surface area and leading to a radical reduction of the size needed (and ultimately the cost) for catalytic and other chemical reactions. Adding a light source as a catalyst to the directed flow of individual molecules in nanotubes allows for extreme control and high efficiency.

Their review 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. 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.

Citation: Nature Photonics, Online Publication September 11 • 10.1038/nphoton.2011.209.
Title: Optofluidics for energy applications
Authors: David Erickson, David Sinton, Demetri Psaltis
Video: http://www.youtube.com/watch?v=-vwQ47TLJrA

Michael Mitchell | EurekAlert!
Further information:
http://www.epfl.ch

More articles from Power and Electrical Engineering:

nachricht Improved stability of plastic light-emitting diodes
19.04.2018 | Max-Planck-Institut für Polymerforschung

nachricht Intelligent components for the power grid of the future
18.04.2018 | Christian-Albrechts-Universität zu Kiel

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>