Sunlight is something we have missed out on, ever since electricity was discovered. With our daily routines getting busier than ever, sitting in our stuffy offices, most of us hardly find time to spend out in the sun. So Anton Harfmann, Associate Dean and Professor of Architecture and Interior Design, and Jason Heikenfeld, Professor of Electrical Engineering, have collaborated on a project that could bring natural daylight to us in the offices.
21% of the electricity consumption in the commercial sector is for lighting purposes. Offices are usually occupied during daytime hours, and natural sunlight delivers a spectrum of light that’s most conducive to productivity and psychological well-being. Hence, it makes much more sense to have as much natural lighting as possible during the duration of office hours. Unfortunately, that is not very easy to execute since not every office has a window, and even where there are windows, the most sunlight these offices get throughout the day is for an interval of a few hours or so, because of the movement of the sun throughout the day.
Light tubes such as the ‘SolaTube’ are often used which offer a low-tech way to bring daylight into windowless rooms. However, they are specifically designed for residential locations and they produce a diffused light that spreads around a room. If you need a bright light on a particular area, you’ll probably have to revert to using an electric light.
But our progress in science does not stop at that. Picture an array of tiny lenses that can redirect sunlight towards any interior room of a building. Even better, the lenses focus light onto any small location for lighting a specific area of the room. Owing to the phenomenal progress in the promising field of electro fluidics by the innovative pair of researchers at the University of Cincinnati, we may see this technology available on commercial level in the near future.
What makes this technology even more flabbergasting is that this SmartLight does not consume any net electricity but instead, offers the possibility of using excess light to generate additional electricity. And it all comes back to a drop of electrically charged fluid, much similar to a pixel in an LCD TV.
How this lighting works is pretty simple. What we would need is transom windows with electrofluidic (EF) cells embedded in them. Light rays enter the building through these arrays of electrofluidic (EF) cells in the windows. This light is then directed up to the ceiling for general room lighting. Concentrated task lighting can also be achieved by arranging the electrofluidic cells in such a way as to focus more light on to specially-designed fixtures. Excess light that remains unused by all the rooms is then redirected to a central location for storage. The room lighting is user-controlled through a smartphone app that communicates with the WiFi-enabled array.
A lot of questions are generally put forth about the construction and composition of electrofluidic (EF) cells. These cells essentially contain a droplet of transparent fluid – just a few millimeters in size – charged negatively. This fluid acts like a lens when a small voltage is applied to one or more sides of the cell, changing the shape of the droplet. It can then focus the incoming light in any direction. Tiny photovoltaic cells are the source of electricity in this case. These are so small in size that they only have the capacity to absorb about 10% of the light. But this is enough to produce the negligible amount of voltage that the electrofluidic cells need.
The voltage is applied sporadically. But according to Dr. Harfmann, the cells would need refreshing every few minutes, in order to retain their shapes and to adapt to changing light conditions caused by the movement of the Sun in the sky during the day. Experimentation is still underway, as Dr. Heikenfeld who has spent several years working on a variety of applications for electrofluidic cells is performing trials and tests on EF cells with various voltage levels and associating controls, that can shape the cells and direct the light. The principle however has proved to work by researchers, who have tested EF cells on a small prototype array of about 6 square centimeters.
Harfmann and Heikenfeld have a brilliant suggestion to make; let’s direct the excess sunlight to a centralized place where it can be concentrated and then passed on to photovoltaic cells. The result of this practice is that electricity can be generated in-situ and later sold or can be stored in batteries for later use. The heat derived from concentration of sunlight can be used to heat up space or to heat water.
Applications for grants for funding a large scale prototype are under process. Researchers expect to have made a working prototype within a year or two. If they manage to find enough investors who are willing to fund this project, we just might see this technology commercially available in a period as less as three years.
This project may seem overly ambitious to many, but it is certainly doable for new constructions, and even as a retrofit on existing buildings. A retrofit however, is not very convenient since that would require transom windows to be installed and the central storage hub does not seem too feasible. But we would at least be able to get natural light in interior rooms. I mean, who would mind some natural sunlight shining down on them in their stuffy offices? I certainly wouldn’t!
