Piping Light
by EcoGeek.org on 11.23.06
The most efficient use of solar power is lighting. Sunlight is already light, no energy is lost in conversion to or from electricity. Thus the success of windows and the more moderate success of skylights. But What if you need the light to get somewhere not directly connected to the outdoors. What if there's three feet of insulation between your wall and the outside, as there probably should be.
You could use expensive fiber optics to move the light around, as we've seen at Treehugger before. Or you could just shunt the light into a highly reflective pipe, and pipe the light into your house. Light pipes are not a new thing, but advances in inexpensive, extremely reflective materials have recently made them more viable. The people at Solatube, for example, seem to have a really great system going.
The cap of the light pipe redirects light straight into the tube no matter where the sun is, and then their proprietary reflective pipe transports the light into the interior will relatively little loss of light. At the end of the tube, a refractive lens or mirror spreads the light through the interior of the building. Their system has already been installed in factories, warehouses, retail stores and homes across America. No word on cost per installation, though I imagine it varies pretty widely. I sure would like to have one in this basement office.
::Colorado Green Business, ::EcoGeek. See also ::Sunpipe by Terry Payne for Monodraught
We were in a lighting store about a year ago that had one of these light tubes installed so we asked the sales person about them. She said they had quit selling them because they couldn't find installers that would get them installed properly. The biggest problem is water leaks through the roof. So if you get one, make sure you get an installer that knows what he/she is doing.
Corey
We have two of these in our house. One in a hallway and one in a bathroom. They are totally awesome!!!
I have 2 in my house (outside of Boston) Works great. With the single story ranch, they are easy to put in.
During the day, you never reach for the light switch when you walk in the room.
I am putting 2 more next week.
Their motion-less tracking of the sun seems like a terrific technology for concentrator applications.
Just add a fresnel lens at the base of the top dome to collect all the rays and then focus them on a high-efficiency triple junction cell below. And you've solved the most pressing problem of solar concentrators - continuous and accurate tracking of the sun.
Btw, Jeff and S.Landau, how much is it?
From the people that have light pipe systems... could you please give us an idea as to cost per unit installed?
They're available at homedepot.com They got a good write-up there.
ODL, Inc.
10 In. Solar Flair Tubular Skylight With Metal Flashing
Model EZ10SCMNH
$179.
I'm an architect and I use solatubes (www.solatube.com) all the time. I've just recently installed 30 24" diameter tubes in a hospital. They were approximately $1500/ea installed. An excellent deal!
Thanks for linking to my story about light pipes at www.coloradogreenbusiness.comBut it's Colorado Green Business.... not California Green Business.
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editor note: Thanks. Fixed.
I live in an old 4-square. The previously dark upstairs hall in the center of the house is now illuminated all day with one Sun Tunnel. Had to add another 4 foot extension - total material cost under $200.
I just had my roof redone and the contractor installed the dome for me - bombproof job for the Northeast. The rest was super easy, about 2 hours time. Now when I go up the stairs, it's like seeing the sun in the ceiling.
Can someone write on the insulation/heat loss issue for this product? If you have three feet of insulation and you stick this tube in the middle of it, what happens to the R-value of the roof? Is the shaft insulated? Thanks.