August 30, 2006 4:00 AM PDT

Let there be light, optical cables included

Office workers toiling under eye-tiring fluorescent bulbs have hope for a brighter day.

A company called Sunlight Direct is developing a hybrid solar lighting system that distributes daylight into buildings through fiber-optic cabling, even to people not seated near windows.

The notion of maximizing outdoor light inside is common in interior design by using various methods, including skylights and even roof-mounted tubes with mirrors.

But Sunlight Direct is taking a high-tech approach by seeking to create a commercial product from Department of Energy research.

Its hybrid solar lighting system features a 40-inch mirrored dish with a GPS-director monitor to move it during the day and maximize light intake. Once light is collected from a roof and concentrated, it is filtered and then spread through a building through bundles of plastic fiber-optic chords.

About 25 retail outlets and office buildings are testing the company's system, which the company hopes to bring to market early next year.

The selling points are lower electricity bills and the benefits that natural light has on people, whether they are employees or customers, according to the company.

"No longer do you need to be the CEO in the corner office. You can have daylight piped into the office," said Duncan Earl, the company's chief technology officer. "Natural lighting is just the best lighting for humans."

A daylight distribution system can reduce the amount of power consumed during the middle of the day, when demand on the electricity grid is highest. Sunlight Direct estimates that its hybrid solar lighting system can result in saving up to $8,000 per year per unit.

Sunlight Direct is one of a growing number of companies seeking business opportunities while energy prices and concerns over the environment are high.

Sunlight Direct system

Another company called Ice Energy, for example, has created a product that was conceived from Department of Energy research.

Its air conditioner, which freezes water at night to cool refrigerant, has become more economically viable because of higher electricity prices and a soaring demand for power worldwide, according to CEO Frank Ramirez.

Happy people buy more
Sunlight Direct's technology, started ten years ago at the Oak Ridge National Laboratory in Oak Ridge, Tenn., originally was conceived with an eye toward energy efficiency, said Earl.

However, Sunlight Direct is finding that the less tangible benefits of natural light on people are also prompting its initial customers to test out the system.

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Daylight in buildings is good for everyone
An important note in the story is that ordinary daylight is the most
pleasing kind of light for people, making them more productive.
It's better for employees, customers, and whoever pays the electric
bill and breathes the air.

There are probably less expensive, more effective ways to bring
daylight in though. Reflective awnings teamed with internal
reflectors on ceilings can bring daylight deep into offices. But let's
see how this complex system stacks up.
Posted by Mark Shapiro (7 comments )
Reply Link Flag
I had this exact idea! Its a good one as well. Especially for big
buildings like the hospital I work in. The area I work in has no
windows at all and i can go for an entire shift with out seeing the
Posted by beardedfish (2 comments )
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Vitamin D benefits?
Natural sunlight helps/causes the body to produce vitamin D. Will the piped sunlight do the same?
Posted by littlejon2 (17 comments )
Reply Link Flag
Probably not
They probably filter out the UV to appease skin cancer fear mongers. So vitamin D benefits will probably be limited. If they do filter out all the UV then it would not be fair to extrapolate skylight effects on mood to lightpipes like this.

I have no doubts that the light 'color' itself is beneficial but the UV stimulating the skin to produce D is one of the major factors to being 'happy' outside.
Posted by NocturnalCT (301 comments )
Reply Link Flag
Meant to reply to the Vit D. question
Posted by NocturnalCT (301 comments )
Link Flag
Probably, but it won't make much difference
First, Vitamin D production is stimulated by UVB, skin cancer is
predominantly caused by UVA, so there is no reason why
cancer-causing spectra can not be filtered out with no effect on
Vitamin D production.
Second, there is no evidence that ingested vitamin D in the diet
is not equivalent to that manufactured in the skin, and a wealth
of evidence to the contrary, so that particular benefit is
Third, while studies DO show that Vitamin D has an effect on
mood, they are also quite clear that this is not the primary
vector by which light exposure affects mood. In fact, the
majority of the mood elevating effect is stimulated by light
impinging on the eye and stimulating the production of
hormones, including melatonin from the pineal, that have little
or nothing to do with Vitamin D levels.
All in all, the benefit of endogenous Vitamin D production in
modern society is overblown.
Posted by DeusExMachina (516 comments )
Link Flag
Why GPS?
Do buildings move a whole lot? I realize GPS receivers are cheap these days but clocks that receive time signals via radio are even cheaper. At least I assume the GPS unit is used to get accurate time information?

Simply initialize the location when installing the unit and take the GPS with you. Then use accurate date/time information to calcuate the position of the sun to aim your collector.
Posted by NocturnalCT (301 comments )
Reply Link Flag
Why time signals?
Simpler still, why not just a light intensity tracking circuit. All the
thing has to do is track the sun across the sky. All it needs to do
that is two photocells and a voltage comparator.
Posted by DeusExMachina (516 comments )
Link Flag
heat gain
I toyed with this in 74 @ VPI. This would also bring in the light without the associated heat gain of windows & skylights. Great concept, but mine also included a 'view' of the outside. We're still not there yet! Congratulations!
Posted by BobAIA (1 comment )
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This really isn't gonna work that well
Am I the only one who realizes this will only work if it is a completely clear day outside. The fact is that anytime a cloud passes over, and early in the morning and at night when its dark, you still have to have electrical lights. I don't believe the cost for this stuff is worth how very little use you can actually get from them. Definitely needs some more innovation and work to be useful.
Posted by thmst30 (33 comments )
Reply Link Flag
Not completely true
Actually, there is a good deal of light in the natural sky without
direct sunlight. It won't be as bright, but as a supplement to indoor
lighting, it would indeed be a benefit. It would also act to tone the
light temperature. Obviously, dreary days would not offer anything,
but to a large building, this does offer some promise.
Posted by jasonemanuelson1 (82 comments )
Link Flag
Why no shielding
I see from the photos that alot of light is escaping in the ceiling because the cable has no reflective shielding. Why?

Posted by kieranmullen (1070 comments )
Reply Link Flag
Not really that much loss
The photo is misleading in that it is looking at the light cables in near total darkness and exposing to emphasize the leakage from the fibers. An optical fiber works on the principle of total internal reflection, so the amount of light the "leaks" out the sides is extremely small. And external reflective shielding would not get the light back into the fiber in a way which would aim it toward the destination.

To be transmitted, light must enter the fiber through an end and leave it through an end. The only exception is when a fiber is deliberately made more leaky by changing the surface, so that it can serve as its own diffuser at the destination end.
Posted by internetdog (8 comments )
Link Flag
in fact, this is no more new technolgy even back to year 2006, Japanese company La For?t (trade name, Himawari) started this daylighting system by optical fiber in year 1978,

Himawari is now very successful in Japan, China and Hong Kong.
Posted by usathomas (2 comments )
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