Making Solar Power at the Office?
It’s easy to power a single-story buildings-worth of electrical needs with a solar roof, but what about the power needs of skyscrapers? They have so little roof space available on top compared to their 40 or 50 floors-worth of electrical needs underneath them.
Here’s one idea. Why stop at sunlight to power solar cells. Let’s harness our fluorescent lighting as well.
New Energy Technologies is trying to develop a solar cell that makes electricity just from that nasty fluorescent tube lighting buzzing over your head.
New Energy’s solar cells in their transparent SolarWindow™ generate electricity by using the visible light in artificial fluorescent lighting typically installed in offices and commercial buildings. In tests published in the Journal of Renewable and Sustainable Energy they outperformed regular solar cells by orders of magnitude; producing two to ten-fold more power.
Researchers tested the ultra-small solar cells on a 1”x1” substrate against today’s popular solar materials for their capacity to produce electricity under varying artificial light conditions, mimicking the levels of light exposure in homes and commercial offices.
Under normal office lighting conditions, without any natural light from windows, New Energy’s ultra-small solar cells produced not just twice the power of monocrystalline silicon, but achieved:
- 8-fold greater output power density than copper-indium-selenide, known for its high optical absorption coefficients and versatile optical and electrical characteristics.
- 10-fold greater output power density than flexible thin-film amorphous-silicon.
(Of course regular solar cells are not designed to make electricity from office lighting. So that may not actually mean much.)
For their first use, the technology application would probably be just in little gizmos like solar calculators and iPods.
But a great application of this would be to embed this transparent material right into the fluorescent fixtures themselves in a layer right below the light. And helping to power it.
Image from Flikr user Ubiquity zh
Via New Energy Technologies
You Might Also Like
Harnessing Kinetic Energy from Marching Soldiers
Burger King to Harness Kinetic Energy from Speed Bumps
September 13th, 2009 at 8:26 pm
“great application”? This only makes sense if the wavelengths you absorb are beyond the visible as the purpose of the fixture is to illuminate the area and your cells would likely counteract that fuction. In addition the cost would have to be less than and energy production greater than just using energy saving LEDs.
In order to calculate the cost effectiveness we need cost, absorbtive wavelengths and energy output data, please?
September 13th, 2009 at 9:38 pm
The purpose of office lighting is to light the office. Wouldn’t it be more efficient to reduce the office lighting to what is neccessary (saving power) and power the devices directly? Office lighting is not “FREE” nor renwable like the sun.
September 13th, 2009 at 10:07 pm
Stupid idea. Like putting a wind generator on top of a car. The solar panels would only make the room darker while capturing but a small fraction of the light’s energy. It would save a LOT more energy to simply put the blinds up on the windows at night to reflect the light back in.
September 13th, 2009 at 10:15 pm
Placing these on windows to capture both incoming light and light that would otherwise escape the office might be an interesting application, but capturing light that would otherwise be used for illumination is counterproductive. As others have mentioned, there are more efficient ways to do that.
As for the test results, besides comparing against cells that aren’t designed for indoor use, are also based on 1″x1″ substrates. Fine if you’re powering a calculator, but for serious power production at low cost you need much larger substrates. Retaining efficiency during scale-up to larger substrates is not trivial.
September 13th, 2009 at 10:15 pm
Great post.. thanks
September 14th, 2009 at 1:34 am
My understanding of “transparent” as quoted by their research means that light passes through the film without losing any intensity.
September 14th, 2009 at 1:41 pm
solar is good energy,it has good future
September 14th, 2009 at 4:25 pm
It is a physical impossibility for a PV cell to both capture a photon for power and pass it through unaltered for illumination. Fluorescent lights are designed to only emit visible light and although the cells may appear transparent, they must necessarily reduce the number of illuminating photons, (or minimally change the wavelength as the fluorescent light does), passing through to produce power. You could still collect energy on desktops, etc. but a cover or reflector on the fixture itself is necessarily defeating the purpose of having a light in the first instance.
September 14th, 2009 at 10:53 pm
Interesting idea and great thought, but I agree with John R. It would require more energy to light the room in this manner. A better idea, put transparent photovoltaic solar panels on all of the windows and roof and use hybrid solar lighting.
September 14th, 2009 at 11:17 pm
The idea of putting the material below the light seems feasible if the “transparent material” is truly transparent … OR simply place the film ABOVE the bulb.
The light transmits all around the flourescent tube and IF the film is transparent or nearly so, it would have no effect on the amount of light reflected from the top of the light fixture.
September 15th, 2009 at 3:05 am
Love the idea of it above the fixture. Hive mind, thanks.
December 16th, 2009 at 2:43 pm
The best thing to put behind the tube is a reflective surface to throw the upwards light back into the room, a mirror can be close to 100% efficient at that simple job.
Converting electricity to light and some back to electricity back to power said light is preposterous nonsense we expect from people with no physics education or even common sense. These things amount to perpetual motion machines which don’t work. Every stage has losses, and fluorescent tubes are only about 20% efficient, the rest is produced as heat but its the best we have right now.
And as others have said, solar cells are never really transparent, and even when they absorb some photons and convert to electricity they also block other wavelengths and convert that to heat.
In general even using solar cells in the office is just plain lazy because the power outlet is literally available a few feet away. There are no cheap efficient solar cells available that warrant use of artificial light. If light is leaving through windows, then use reflective blinds. If light is entering the windows, turn the lighting down.