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.

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?

[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

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.

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.

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.