Student Develops Inexpensive Solar Lens To Purify Water

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nigeltm

Full Member
Aug 8, 2008
484
16
54
south Wales
This was featured on Doomsday Preppers some time ago. The guy in Florida used a frensel lens salvaged from a old CRT large screen TV with a photocell setup to track the sun position and a threaded bar/electric drill to move the position the lens. It was hot enough to melt zinc pellets!

The water purification was interesting. Water from a pond in a glass jar with some dark stones (to absorb the heat). The water happily boiled away!

It worked very well in Florida and would work well in Africa (if they can find enough old TVs!). It would be interesting to try in the UK.
 

Toddy

Mod
Mod
Jan 21, 2005
38,937
4,570
S. Lanarkshire
That sounds really practical :D


On a side note though.....how come rinsed out soft drinks bottles, freshly filled with tap water (that has a faint smell of chlorine) put into the greenhouse to be used to water plants, always end up with green algae in them if left for more than a few days ? :dunno:
How the hang did the live algae manage to get into the sealed bottle. The only place I can see is from the tap water, but surely the chlorine would have stopped that ?

M
 

cranmere

Settler
Mar 7, 2014
992
2
Somerset, England
Some of the blue-green algae are highly chlorine resistant and they also form biofilms that protect the underneath layers. In a greenhouse at least some of the UV will be filtered out by the glass too.
 

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