Fiber Optics Bring the Sun Indoors

Sterling D. Allan writes "Fiber optics transmit light, so why not take the light from outside and transmit it inside? According to an exclusive story at PESN, that is what Tennessee company, Sunlight Direct, is now doing. Their 4-foot-diameter solar dish will light 1000 square feet inside -- minus the harmful UV rays -- rendering a more natural lighting feel, which can be hybridized with florescent and possibly LED lighting to provide a constant light level, though the tone changes with the level of light outside. The GPS-based sun-tracking mechanism uses very little energy. Now you can save electricity, cut on heat emissions by incandescent, and improve the feel of your work environment. Beta testing began in June. Product expected in the market in 2007."

Comments

Very cool

[JasonBee]

In the Australian interior (Coober Pedy and Lightning Ridge) they build many homes undergound...thsi kinds of thing would be perfect. Natural air conditioning and natural light sources.

Re:Very cool

[yobbo]

This will be handy in the cities as well. A common problem with converting old office space to residential uses is the inability to get sufficient sunlight deep into the building. This technology could help alleviate the problem.

Re:Very cool

[GloomE]

With the energy density you'd be playing with why use fibres?
Wouldn't you do the Julian May thing and just build huge evacuated tubes with mirrors every few kilometres to account for the curvature or the Earth?
Is there a gas we could use instead of a nasty vacuum?

Re:Very cool

[OreoCookie]

Orbiting mirrors. http://www.aeronautics.ru/mir06.htm http://ucsu.colorado.edu/~browndp/web4d.html

Old News

[sakusha]

The Ark Mori Building in Tokyo had a fiber optic solar light distribution system installed something like 10 years ago. I remember seeing a video of the system. It's been out for 10 years, but nobody did anything to follow it. My conclusion: it's worthless.

Not that new under the sun

[soward]

This doesn't seem that new. Folx have had large-scale "fibre optic" types of skylights that can reach to basements and other areas for quite some time. I think they are even available at Home Depot.

www.solartube.com comes to mind right off the bat...

Skylights are nice

[ReformedExCon]

Even when raining, the outdoor light feels much more comfortable and natural than indoor incandescent lightbulbs. I imagine the idea has been around since Gog the Hut Thatcher fell through one of his creations and the hut owners just left the hole in the roof.

Nowadays, they've got a nice system where the light is guided through a reflective tube that can be directed to any room in the house.

http://www.solatube.com/

It was only natural that the techonology would progress to where we are splitting the sunshine into fiber optics and redirecting them all over the house. However, 2007 is a pretty long way off for what seems to be a relatively simple application of existing technologies.

Photonic Storage?

[Doc Ruby]

Is there any way to store the photons in sunlight? Not convert them to electrons, then reemit them, but "trap" the photons in some medium, then emit them at some arbitrary later date? Without transforming some amount of their energy to heat or other mechanical energy. For retransmission later, like when the sun goes down.

Maybe a nanomaze of fiber, a few wavelengths in diameter, twisting its way around inside a cubic centimeter? If such a "photon trap" were millions of meters in length, it might be able to absorb photons for a while, before the first ones trapped finally made their way around the loop to the surface, during which time the trap could be closed (with a mirror, cycling the photons through the circuit until it was opened again. Or maybe an input window that's mirrored only on the inside, trapping photons continuously, until another mirrored facet is removed. Or a spiral maze of MEMs mirrors which send light around the cycle, until one is tilted away from the cycle, towards the output.

Is there any kind of work on "photonic storage"?

Re:Photonic Storage?

[renehollan]

Google for Slow Glass.

Re:Photonic Storage?

[Doc Ruby]

What if the mirrors aren't flat "silvered" reflectors (how does that do it, anyway?), but instead just loops of fiber, never at less than the critical refractive angle? Perhaps doped for soliton organization? The efficiency probably won't ever be 100% "reflective", until we build the structures out of individual electrons, probably in a vacuum, in microgravity. Or around a nano-black-hole, perhaps a magnetically contained all-strange mass in a vacuum.

Until then, is there any way to just charge a photonic crystal with 4m^2 sunlight all day, and get 1m^2 sunlight all night? Only 75% decay over 12h?

Re:Photonic Storage?

[TigerNut]

Even if total internal reflection were 100% efficient (and it can't be), you'd be left with an interesting problem... How do you get the light in? The refractive index of glass is such that the angle of an incident light beam gets closer to normal (perpendicular to the interface plane), compared to the source. So shining a beam of light onto the surface of a perfect quartz torus (of arbitrary length or number of turns) will just cause most of the beam to be refracted such that it can exit on the opposite torus wall. The remainder of the beam will get internally reflected, but at pretty close to the critical angle, and then you can't get it out... If the reflection and transmission of light in a particular crystal were any given number of 9's (i.e. 0.9999999999999999999...90), it would still only take a finite number of reflections or molecular interactions for the photon to lose it's energy to the crystal as heat.

One good idea (for the whole light-pipe business) would be to take the UV energy that is reflected or filtered, and use it to energize a fluorescent radiator whose output could then augment the visible light collected by the system. Since there are some fluorescent materials with extended decay times, that might buy you some 'charge' time.

Re:Photonic Storage?

[Alomex]

How do you get the light in? The refractive index of glass is such that the angle of an incident light beam gets closer to normal (perpendicular to the interface plane), compared to the source.

This is a geometric problem which has been solved by mathematicians. The light trap looks like an egg with part of the lateral wall removed. The "egg" itself is made of portions of a paraboloid and an ellipsoid. The light gets trapped in the ellipsoid, bouncing on a trajectory ever closer to the major axis of the ellipsoid, i.e. the line joining the foci.

Re:Photonic Storage?

[StarsAreAlsoFire]

There are methods of storing photonic energy (is that a real term?) as chemical energy. It is called glow paint ;~) But yeah, I think that falls under 'convert to electrons', or close.

Seriously though, there is no possible way to do what you want using mirrors, because there is no perfect mirror. And saying 'fiber' just means using mirrors (fiber reflects light down its length). What you want would be a lossless (or really damned close to lossless) method of focusing light: that method is gravity. One could conceive of (probably not implement though) a system where you had a perfect gravitational loop (e.g. by moving stars around to suit your purpose) and one could add light into this loop by aiming a laser properly, or a deft us of mirrors (you would only use the mirror for one reflection, gravity does the rest).

The reason this wouldn't REALLY work is that while light (photons) doesn't/don't have mass, it has momentum. So changing the direction of a whole boat load of photons would in fact wreak havoc on the perfect circle of a gravity well you created (the stars would be moved). I think. That, and good luck moving stars around ;~)

So, short answer to second paragraph: Won't ever work. Cool thought though.

Short answer to first paragraph: It's called a black hole :~) And you CAN get the energy back. But probably not in the same frequency of light that went in.

But then, if we have a stable black hole to play with, we certainly would have no need of storing photons :~) Toss in a bit of matter, catch the high-energy radiation as it gets ripped to shreds, convert to as much energy as you could possibly desire. More efficient than matter-antimatter, and far more efficient than a fusion reaction. I have about a 60% certainty level on the matter-antimatter part of that statement; verification would be wonderful. I can't remember where I read it, if in fact I really did :~)

Cheers

Re:Filter the UV rays

[IconBasedIdea]

Both the first paragraph of the article AND the description answer your concerns about harmful rays. Good job paying attention...

The author also wrote about alien technology!

[EnronHaliburton2004]

Not to bash this solar lighting system or anything, but the author of the article is a bit of a nutcase-- she wrote a whole article about how we're all doomed because of the impending Magnetic Field Revesal, and another article about a scientist was killed in a conspiratorial fashion because of his "new energy" discoveries, which apparently came from space aliens.

So take this article with a big grain of alien-free salt.

Arcology lighting

[davedx]

This would be fantastic for lighting the insides of Arcologies. Something I've always thought was a big negative for city sized buildings is whereas you have a huge volume for everything you have relatively less surface area for windows, and as someone else posted here lack of natural light can be really bad for you... in a large-sized arcology you'd have huge sections with no windows...

Just a random thought on an application.

Elevators

[revscat]

I wonder if these could be made to work in elevators? You could have the fibers going straight down from the roof, say one for each corner of the elevator. They would be shielded in a translucent tube so that the passengers couldn't obviously touch them. And since you have a natural shaft to the roof already, this seems like it would be a good fit.

The main benefit would be the lessened heat dissipation. I've been in far too many elevators that have what seems like way too many incandescents in the roof that make the elevator very hot, especially this time of year.

Let's do some maths.

[Anonymous Coward]

$US8000 for one of these systems, capable of lighting 1000 square feet. That's $US8 per square foot; I'm Australian, so let's work in Australian dollars: around $10 Australian per square foot. A typical fluorescent light bulb (to replace an incandescent bulb) uses 15 watts of electricity.

Looking at my latest electricity bill, I'm charged 13 cents (Australian, roughly) per kilowatt hour. Ten dollars is 77 kilowatt hours; that's equivalent to running one of those things for 5,000 hours (again, roughly).

Working period is 8 hours a day, five days a week -- forty hours a week. 5,000 hours is therefore 125 weeks, or about two and a half years. Multiply that figure by the number of square feet a standard bulb can illuminate (it'd be, what, about 50 square feet at a guess?), and you have a break-even point of 125 years.

If they're replacing incandescent bulbs (which use four times the electricity), break even comes down to about 30 years.

Points to consider:

1. My pricing for electricity is residential rates. Industrial and commercial rates are probably different. Anybody have solid figures?
2. I'm guessing with the 50 square feet per bulb. If a bulb can light more area, the time to breakeven increases accordingly. If less, it decreases.
3. Businesses typically use fluorescent tubes, not bulb replacements. I don't know how much energy those use, nor how much area they can light.
4. Does this price include installation? If not, there's an added expense before break even is reached.
5. You'll also need other lighting to supplement this system on badly overcast days, and at night, reducing the payoff.

The price will have to drop a bit based upon my back-of-the-envelope calculations before this becomes viable. If anybody has better figures than the ones I've given, please, speak up -- I'm genuinely curious. In particular, I don't know how much electricity costs a business in the USA; that is the single biggest factor in determining payoff time.

This is new?

[Tehrasha]

I could swear I remember a TV news report from the late 80s early 90s where this was being done in one of the new skyscrapers in Japan.

Re:Geomagnetic reversal happens, but aliens don't

[EnronHaliburton2004]

Sure, the field will reverse some day. But what does that have to do with alternative energy sources?

I can prepare for Magnetic Field Reversal like I can prepare for a really big comet-earth collision. I'd rather focus on the more likely tangable problems.

In my experience, Magnetic Field Reversal is a story mostly used by crackpots to sell survival equipment.

I went to College with people who fled to the hills to prepare for the eventual Magnetic Field Reversal-- that was supposed to happen around year 2000 (I told them that magnets don't follow the Christian calendar) Now it hasn't happened, so they moved the date to 2012, which is a signifigant date on the Mayan calendar.

In High School, I knew people who stocked up on supplies to prepare for Revelations, which they thought would start in 1996.

I'm not kidding.

Not new to me

[PorkNutz]

This has been done in the DIY energy crowd for years. I know a fellow in Washington with an underground house that built a solar lighting system using the exact same methods.... 20 years ago. He told me the hardest part about building the system was building the light "wiring harness". He used pine trees to stretch and direct mono filament fishing line into the right paths, and then wrapped the whole thing in mylar strips followed by electrical tape.

The collector mirror... you guessed it, a big ugly satellite dish that he bartered to have chrome plated, and a DIY sun tracking system that is powered by the sunlight it tracks!. The system provides more than enough light to light up his place, though it is a bit weird when clouds pass overhead.

At night and on stormy days he uses stored energy from solar panels. He used to use a 12 volt system, now he uses compact fluorescent bulbs and inverters. His entire nightime lighting system (every light in the house) uses less than 300 watts, where before he calculated it to use almost 800.

Solar Energy:

[purduephotog]

$8k will install at least a 2KW system.

And that's from a licensed dealer who's making money hand over fist as the panels can be had for around 600$, the connection equipment and batteries add up.

Now lets reject the IR into a water-tube to capture that as surplus energy too and we've got a better system that costs less...

Re:no

[robotito]

I thought some colombian narcos were using this technology already in order to seed "things" underneath the Earth and not to be seen by the hunting helicopters, maybe was an hoax, doesn't know.

Re:Geomagnetic reversal happens, but aliens don't

[Khyber]

How much would a metric ass load of honeybees weigh if converted to Imperial??