Liters of Light

Looks like it will leak like a sieve...better include a can of

The picture and explanation shown are wrong - in a way that could be deadly.

The picture shows ammonia, but the description says bleach.

Ammonia + bleach = toxic vapors.

http://chemistry.about.com/b/2010/08/20/why-you-shouldnt-mix-bleach-and-ammonia-bleach-and-ammonia-chemical-reactions.htm

Hate to say it, but the alkalinity of bleach will eventually break down that PET pop bottle- who wants a bleach shower?

Just make sure they pick the right type of bottle!!!!

I think it would be better to make a corrugated strip of plastic from the bottles, and have more light....

http://www.trashbackwards.com/solutions/2610/Plastic-Soda-Bottle-Roofing

I think you all miss the point here!

SE: first response is nonsense.

usb: The intended users won't be watching on their laptops nor following the link you provide. They don't have laptops. They don't have electricity!

JNB: They don't have a wide selection of bottles. Maybe no selection.

SE: Considering the end user, not an option.

These people are poorer than we can comprehend, obviously. Not even sure where they'll get the ammonia, or bleach.

I can sort of relate to this. Where I grew up, electricity was our only "luxury".

Water and toilet were outside. Horses did the work. Everything else was done by hand. I know primitive, it ain't easy.

Primitive!? They seem to have plenty of aluminum corrugated sheet, and a very specific type of caulk....Why when I was a kid we pumped water by hand in the front yard, had a one hole outhouse that had been there so long it was worn smooth, and foraged for food on the land, and went to a one room schoolhouse, where we only had one game, steal the bacon....Why we were so poor we had a hand-me-down-dog that used to guard the front door, even from us....and I know for a fact that any hole some amateur puts in a roof, is going to leak....Why we were so poor we couldn't pay attention...

The sheet is scavenged - the caulk is going to be tough. These people are far more poor than you describe.

I actually agree with what you say, and was thinking that most of this would probably be scavenged anyways- the bigger problem is likely where they would get the sealant. In that case they probably can get good old fashioned glass bottles almost as easily, which might be a better choice.

My point is that someone thought this idea up, and if they'd actually put some basic research into it they would be disseminating a good idea instead of a potential liability. People in this sort of situation have enough of those without well intentioned helpers making it worse.

The intended users won't be watching on their laptops...

Seriously?

My comment wasn't aimed at 'the users' it was aimed at Chelsey who wrote 'bleach' (as was in the video) but had a diagram that showed 'ammonia'. I assume she knows the difference between them, but I was wondering if she is aware of the toxic combination one gets when the two are mixed.

In either event, a drop of white paint in the water would be a better diffuser of the light than bleach. Also it would be about as easy to obtain as the plastic bottle (even primitive cultures have access to, or a method of making, white paint); it would likely be easier to obtain than the bleach.

I was in touch with a company in USA which makes special paint which retains light and keeps emitting light for many hours- depending on chemical used. Of course the lumen output degrades with passage of time- but time it lasts can be of the order of few minutes to even 15 hours etc. In Mumbai, India we have a company which makes similar paint. Remebr Madame Curie's discovery of radium !!! But Radium is basically green (I think ZnO). You will find long persistence phosphor sources on internet. But there are a few which can give yellow or white. In fact thin double walled glass panel with this coating in between (so taht it does not get affected by collection of dust) - built into the ceiling amy give light during day as as for many hours after sunset!!!! I was keen on circulating this idea- it will be at fraction of teh cost of solar energy- even for garden lighting, beach resorts, hotels for outdoor service under umbrellas- covered with this painted umbrella etc. No more candle light- but have long lasting sunlight!!!

Those high-persistence phosphorescent compounds are based on strontium aluminate doped with various rare earths. They glow for up to 12 hours (green and aqua) to as little as two hours, for violet. Compared to the old-school zinc- or calcium sulfide-based phosphors, they're very expensive and still not bright enough to be practical for nightime lighting.

The people using these soda-bottle light pipes are desperately poor. Unimaginably poor. That light pipe is the highest tech many of these people will ever see. SrAl phosphors are for people like you and me; people who, from their point-of-view, are unimaginably rich. One ounce of SrAl phosphor would cost more than these people earn in a year, if they earn anything at all. Not practical. To us these soda bottles are rubbish and to them available for re-use. Pretty cool idea.

A dumb, country club type of idea - you live there - you know how much disposable income these people in the slums have!

Maybe he is blind. There are different kinds of blindness. Most are voluntary.

Mumbai's is the world's largest slum, and in a nation of slums.

Is there a great shortage of candles in the Phillipines?

If they need natural light inside a rudimentary house, why not teach them how too make a window? A simple hole covered by a flap of something to alow it to be closed in bad weather/night would seem like a good idea.

Packed in a slum in Mumbai (or other equally nasty slum), one might be lucky to have access to a wall or roof - you can not imagine what they are like.

Nowhere to put windows.

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Some have windows. More often than not they're just gaps where things don't line up.

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These slums look bad. They smell worse. In Mumbai a million people packed like sardines and no sanitation. Like living in a dumpster full of feces, urine and rotting filth on a hot summer day, every single day, year after year.

Look up this link

https://www.dropbox.com/s/ukmuc5vogqad3to/SOLARLIGHT.ppt

Cheapest Solar Lighting beyond sunset hours without electrical energy.

Sorry, my mobile doesn't speak PowerPoint. Alternative format available?

Nice website here on African plans for minimal infrastructure....

http://www.un.org/africarenewal/magazine/october-2006/solar-power-cheap-energy-source-africa

Article on new material being considered for solar pv cells....

"Perovskites have been known for over a century, but no one thought to try them in solar cells until relatively recently. The particular material the researchers are using is very good at absorbing light. While conventional silicon solar panels use materials that are about 180 micrometers thick, the new solar cells use less than one micrometer of material to capture the same amount of sunlight. The pigment is a semiconductor that is also good at transporting the electric charge created when light hits it.

"The material is dirt cheap," says Michael Grätzel, who is famous within the solar industry for inventing a type of solar cell that bears his name. His group has produced the most efficient perovskite solar cells so far-they convert 15 percent of the energy in sunlight into electricity, far more than other cheap-to-make solar cells. Based on its performance so far, and on its known light-conversion properties, researchers say its efficiency could easily rise as high as 20 to 25 percent, which is as good as the record efficiencies (typically achieved in labs) of the most common types of solar cells today. The efficiencies of mass-produced solar cells may be lower. "

http://www.technologyreview.com/news/517811/a-material-that-could-make-solar-power-dirt-cheap/

Update....

"Since then, photovoltaic cell efficiencies have ticked up further, to 17.9 percent-an advance achieved by Sang Il Seok at the Korean Research Institute of Chemical Technology in Daejeon."

http://spectrum.ieee.org/energywise/green-tech/solar/two-labs-get-the-lead-out-of-promising-perovskite-solar-cells

These are promising developments. Thanks for posting these links, SE.

Wow! A big change not! University lab stuff takes years to get into the commercial and residential worlds - if it ever makes it.

See dropbox link - now it is pdf format

https://www.dropbox.com/s/wbq3h2scizx5e24/SOLARLIGHT.pdf

Very familiar with these phosphors.

Here's a link to an old post of mine where I show some pix of the various phosphors' colors. Scroll to the end for these, or read the whole thread if you want. Be forewarned that my post was a premeditated April Fool's Day prank. Its 'victims' were not at all happy they'd been snagged lol. I think some are STILL mad at me.

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http://cr4.globalspec.com/thread/77012#comment840080

Decades ago analog storage Oscilloscopes had a long persistence phosphor- so that you could save the waveform and study. You could save the fast transient one shot waveform and study later. These could save waveforms for many minutes. These phosphors were green or blue. Hence to get yellow- you need red component- which this company in Boston claims. You could look up US patent 6117362 Long persistence phosphor blue colour. I did meet an Indian company in Jan 2014 at an exhibition which claims to give persistence fro 8 to 10 hours or more.

Concept is not new.

Analog storage oscilloscopes do not depend on the persistence of the phosphor to maintain the image, but on a special screen inside the CRT which stores a pattern of charge corresponding to the oscillogram. It is clear that the persistence does not depend on the phosphor because this feature can be switched off at the push of a button and the oscilloscope used in the usual fashion. The phosphor is in fact a very *short-persistence* phosphor for this very reason.

Great idea for use in the slums - you plan to give them away I suppose - no one that needs this type of light can afford them.

Good thing for Alfredo is they won't afford lawyers to sue him. S.M.