SmartLight redirects sunlight into "light-locked" building interiors


November 6, 2013

SmartLight could direct light from outside (far right), through a building, and to a centralized energy-harvesting and -storage hub (far left) (Image: Timothy Zarki)

SmartLight could direct light from outside (far right), through a building, and to a centralized energy-harvesting and -storage hub (far left) (Image: Timothy Zarki)

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Researchers at the University of Cincinnati have developed technology that could help cut lighting energy costs by brightening up rooms with natural light. The SmartLight system is designed to direct sunlight into dark, dingy rooms located within the bowels of buildings without requiring the installation of new wiring, ducts, tubes or cables. It also allows excess light to be harnessed and centrally stored to provide energy for electric lighting on cloudy days.

The heart of the system are tiny electrofluidic cells measuring just a few millimeters wide that are filled with fluid that has optical properties as good as or better than glass. The surface tension of this fluid can be rapidly manipulated to transform the cells into lenses or prisms to control the sunlight passing through them. This manipulation is powered by photovoltaics embedded in the cells and requires 10,000 to 100,000 times less power than is used by a traditional incandescent lightbulb.

The cells are formed into a narrow grid that is positioned near the top of a window and can be used to direct sunlight onto the ceiling to provide ambient room lighting, focused toward special fixtures for localized workspace lighting, or transmitted across the room just below the ceiling to another previously "light-locked" room that has been fitted with its own electrofluidic grid.

"You're using space that's entirely available already," says Jason Heikenfeld who developed the system with Anton Harfmann. "Even if I want to retrofit to existing architecture, I've got the space and the ability to do so, and you don't need something mechanical and bulky, like a motor whirring in the corner of your office steering the light. It just looks like a piece of glass that all of a sudden switches."

Instead of wall switches, the SmartLight system would be controlled via a smartphone app that would allow users to set their lighting preferences and the system would automatically adjust the room's brightness accordingly. The team says that because the individual cells are able to react to changing light levels so rapidly, the SmartLight system can ensure constant light levels throughout the day.

The pair envisages functionality extending to using a smartphone's geolocation data to allow the system to automatically adjust the lighting when a person enters or leaves a room or to communicate with Wi-Fi-enabled light fixtures to alter the lighting when a person switches seats.

Because a typical sunny day would produce plenty of surplus light, the system could direct this to a centralized energy-harvesting and –storing hub within a building to power electrical lighting at night or on cloudy days. The stockpiled energy could also be used for other electrical applications, such as heating and cooling.

Although the pair are currently seeking funding to attract the attention of government or industry partners to help bring the SmartLight system to market, Heikenfeld says that much of the technology required to make SmartLight commercially viable already exists.

"We're going to look for some substantial funds to really put a meaningful program together," says Heikenfeld. "We've already done a lot of the seed work. We're at the point where it would be a big, commercially driven type of effort. The next step is the tough part. How do you translate that into commercial products?"

Heikenfeld and Harfmann recently presented a research paper on their SmartLight system at the CasaClima International energy forum in Italy.

Source: University of Cincinnati

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Really love the idea. There are, however, some issues to deal with: - The sunlight angle changes during the year - Rain and snow issues on the mirrors - overhaniging roofs

to begin with

Vincent Bevort

Awesome SimTower mod!


The energy savings is valuable of course, but having developed older building with dark interior spaces for residential reuse it is soon apparent that light is only part of the issue. People want to see the outside world. This helps thought for the obvious reasons.


Good idea, if it works as described.

However, like so many building technologies today, it relies on a smartphone app to make it function.

And what happens when that particular smartphone becomes obsolete? Surely it is not beyond the designers to rig up a simple circuitboard within a wall plate? Eventually buildings will have to have a whole stack of obsolete phones on hand to work the various building technologies, to go along with the handful of IR remote controls that are now necessary to perform such simple tasks as operating the TV, with all its various black boxes...


is not this just prismatic glass, with the added complications and the drawback of not working in a power outage?

Peter Justice

Sounds clever, if the previously-commented drawbacks can be worked around in a simple way. I agree controlling via an 'app' is problematic, if colleagues have a tiff for instance, you could get "warring iPhones" all around the building! Surely sensors in the darker room could direct a central controller to route light or power to the needed site?

The Skud

@bergamot69 smartphone obsolescence is not a problem as the issue is not hardware the real control over the system is just a app or program you can transfer update and so on to any transmission capable device with memory and processing.

Joseph Mertens

Using fibre optics to channel natural sunlight to all dark areas, corners, corridors of any large building which not only saves energy, but kills bacteria and makes place more hygienic

Dawar Saify

not everybody lives in areas with cell service nor can afford smartphone service to begin with. bring back the wall switch!

Abby Normal
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