Free solar light bulbs from recycled 2 liter bottles

The more I think about this, the more practical it seems. For suburban sheds and small rural barns without electricity I can see the uses:

http://www.youtube.com/watch?feature=player_embedded&v=_zMAWztZ6TI

Brazilian favela-dwellers without reliable electricity have an alternative means of supplying light to enclosed spaces that have no/insufficient windows (either because they are abutted on all sides by other buildings, or because the walls are made of materials that make it impractical to add windows). They suspend 2l soda bottles filled with a water/bleach solution from the ceiling, with the open tops poking out into the daylight. Sunlight refracts off the water in the bottle and turns it into a "lightbulb" that has been measured as supplying illumination comparable to a 50w incandescent bulb.



edited to add pic.

good luck with that one :)

could take another container and cut out a square patch and duct tape it over the hole in the roof.

Bleach should lower the freezing point a little bit, but I suppose it would still be a problem in cold winter places. Perhaps leaving enough room for the water to expand?

The bottle expands with each freeze/thaw and makes the roof leak a little bit more each time. Until the bottle splits. Then it leaks a lot.

but, yeah, freezing will be a problem, and as you point out even if the bottle doesn't break it could still cause other problems.

They ALWAYS start leaking after about 2 mos.

PH

But my toilet vents though a 4" pipe that protrudes straight up though the roof. Has for years without a leak. Maybe it's because I have shingles.

I was considering this solar project projecting horizontally through a south wall above my workbench. There never seems to be enough light there for my aging eyes. With cheap tin reflectors surrounding the top side of the bottles, I think it may be a plus. I wonder if the bleach lowers the freezing point. I can check with a car radiator antifreeze tester.

On edit:
I experimented by shining a Mag Light up through the bottom of a full Mountain Dew bottle. It's amazing how much radiated light is produced in all directions. Cool green color too. I'm sure inputting direct sunlight will be brighter.

it was too expensive for people to afford during daylight hours. One article I read on this showed an indoor toilet before and after: since windows are also too expensive for most people, this loo was pitch dark until the soda bottle lights went in. The woman's smile said just about everything anyone could possibly think of to say.

Another application was a metal shop that had them every few feet in a grid. Workers said the light was better than the inadequate fluorescent bulbs had been.

Apparently these things are fitted so tightly into the corrugated metal roofs that they don't leak during rainstorms.

There are engineering types all over the place trying to figure out free energy solutions to many common problems, from lighting to refrigeration to transportation. Some, like this one, are ingenious.

Also it quits working when she goes to bed a 9;00 pm.

That's hilarious.

Some folks have no idea how solutions which are "free" or "low cost" can mean a world of difference to some people.

Thanks for sharing.

:kick: