Pumping Sunlight Into Homes

ByronScott sends a snippet from Inhabitat that begins "What if you could light your entire building using no electricity or artificial lights – but just the natural light from our favorite star, the Sun? Enter the Sundolier, a powerful sunlight transport system that's like putting a solar robot on your roof to pump sunlight indoors. The manufacturer claims a single Sundolier unit can provide enough light to illuminate a 1,000-2,500 sq. ft. area [93-232 sq. m] without any other sources." The company's website is a bit thin on details, such as what happens on cloudy days, or how many days of sunlight per year on average are needed for the device to perform acceptably.

Comments

There are no details

[BobPaul]

It's thin on the details because there are no details. This is just a flexible aluminum tube and a diffuser. The only thing different about this than the kits you can get at Menards is the big collector array which tracks the sun.

There's no solar panels in this system. On cloudy days, you use electric lighting.

Our Sundolier delivers sunlight so effectively that electric lighting can be turned off when the sun is out offering excellent opportunities to save electricity while reducing heat generation through cool indirect daylighting.

There's no mention anywhere, not in the inhabitat.com article, nor the companies website, that this does anything on cloudy days.

Re:There are no details

[cptdondo]

OK, they're officially call "Deck Prisms".

http://glassian.org/Prism/Deck/index.html

50W lightbulb using a common 2L Bottle

[Hadlock]

This has been done in the 3rd world for ages. You drill a hole in your roof, mount a 2L soda bottle filled with water (and two cap-fulls of bleach to keep it clean and clear), and stick an old black plastic film canister overtop of the white lid to keep the plastic from degrading. The video of these in use is amazing. Sadly however it only works when the sun is up - which is most of the workday (12 hrs typically) in the tropics.
 
Watch it in action. Wow. http://www.youtube.com/watch?v=_zMAWztZ6TI

Re:50W lightbulb using a common 2L Bottle

[value_added]

Maybe you're the person to ask ...

Some years back I stopped for a meal at a restaurant in the historical district of a small town here in California. The restaurant was a converted barn of some sort and had two large double doors for an entrance. During business hours, those doors were left open, as were another set of interior doors that led to an open air patio outside. Hanging on the wall by each sets of doors was a large 1-quart ziplock bag. The bag was filled with water.

Noticing the bags, I asked the owner about them. She told me they were there to keep the flies from coming into the restaurant. I asked how a water-filled bag worked to keep flies away, and she said, "No idea, but do you see any flies in here?" Indeed, there were no flies to be seen (though there were some outside). She went on to tell me that that they had a regular fly problem years back, and one day a local immigrant gardner suggested the bags. The rest, as they say, is history.

I'd guess an entomologist might be the one to ask, but have you heard of this technique being used?

Re:50W lightbulb using a common 2L Bottle

[masterQba]

http://www.straightdope.com/columns/read/1956/whats-the-purpose-of-bags-of-water-hanging-in-restaurants/ The water bag acts as a lens that enhances movement. The flies react to the movement - they stay away.

Re:50W lightbulb using a common 2L Bottle

[Lumpy]

You can do the same with acrylic rods. We did that for a insulated ceiling building in northern Michigan. we had the top of the rod cut at an angle and had that angle set to the south east as lighting was more important to be bright in the morning. 3 foot long 4" diameter clear rod cost less than $40.00 each and the cutting and polishing was done on site with a saw and acetone. inside was crudely faceted to spread the light around, shaft was painted with white wall paint.. plus you dont get a heat loss out of them unlike the reflective tubes with single layer plastic caps at each end that cost far more and are far harder to install.

Re:Huh?

[BobPaul]

The collector has servo motors so it can track the sun and maximize the amount of light sent to the diffuser. Otherwise it's just the same standard aluminum tubes you'd find in any solar collector installation.

Technique can also be used with lamps

[Anonymous Coward]

This is actually a new twist on an old invention which was used by medieval types. They had glass globes that they filled with water and placed around lamps in order to improve the relatively poor lamp light.

Mixing CTB and CTO

[Anonymous Coward]

I noticed that they are mixing color temperatures in that video.

Sunlight is CTB-- "color-temperature blue" -- about 6500 Kelvin.
Tungsten lights are CTO - "color-temperature orange" -- about 3200 Kelvin

When you have a big skylight but use tungsten lamps to light the same room, the effect is this weird blue/orange clashing effect where areas lit by the different light sources appear to have different hues. The same thing is common in grade schools or offices where blue light from the windows collides with the greenish or yellowish flickering light of fluorescents. Photographers may be especially familiar with the idea of color correction to keep the colors appearing uniform. If you mix bulbs in the tungsten spectrum with these bottles or the horizontal lighting cutout panels we call "windows", you may want to get specially color-balanced lightbulbs with the blue color so they don't clash.

Re:Bradbury story -- it was Bob Shaw

[andrewbaldwin]

I think you mean "Other Days, Other Eyes" by Bob Shaw

Thanks for reminding me -- I read it many years ago and enjoyed it - may re-read it now :-)

It also appeals to another Slashdot meme - an evil government using crop-dusters to sow millions of shards of 'slow glass' to act as passive surveillance.

Re:Why haven't these been around?

[eclectro]

I've wondered for years why nobody made something like this... (Or have they, and I just didn't know about it?)

You just haven't known about it. This is a variation upon a theme of the solar tube. You can even get them in Costco now for under $200 USD each. Though this company appears to be trying to patent this very specific design, a parabolic collector feeding sunlight indoors is not new, and much of the technology is in the public domain and used with varying degrees of success. Naturally, you'll have a higher performing system the more money you put into it, but a good ROI is difficult to achieve as with any solar product. Of course, there also is something to be said for getting off the grid (and more reliability outside of cloudy days) in itself, which may be difficult to put a price on.

Re:What distinguishes this from, say, Solatube?

[Ubergrendle]

That was my take...what is old is new again, but they've been selling these in canada for about 10 years (at least). Because the collector is raised off the roof and half spherical, it takes a substantial snowfall to cover the light collector...its maybe ineffective 1-2 months of the year.

Already done.. and better.

[Anonymous Coward]

This has already been done in a much more elegant fashion.

http://www.parans.com

Cost

[Anomalyst]

Per their company president: $15K + install