Survivalism & Self Sufficiency Topics > Food Preps

Fresnel Lens for Solar Oven

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creuzerm:
My office has an old rear projection TV that recently died. When it gets tossed, I am going to raid the dumpster for the Fresnel lens in it. 2x3 feet? lots of solar power concentrated down.

Solar oven, a lens for a solar panel so it gets more light, etc. Lots of uses.

I wonder if you curve it a little if they will focus into a horizontal band instead of a point. You don't want them to actually come to focus onto a pot, not a big one at least, as it can get hot enough to melt metal. But a out of focus bright band that covers the pot set up so that as the sun moves, the band will keep on the pot.  A back reflector to reflect the light that missed the pot back onto it, you could probably get a pot quite hot for a good period of time.

Steve W:
Acquired a nice size Spot version (28 in x 40 in) to experiment with.

These lenses have several different configurations, varying focus & focal lengths, and varying materials.

Will be fun to experiment.  We have a small sterling engine to run up wit this lens once I construct stands for all the components.

HelenWheels:
http://www.youtube.com/user/GREENPOWERSCIENCE

This guy does a LOT of things with Fresnel lenses. There are a couple of youtube videos where they're using the Fresnel aid in cooking.

Gadget:
On a similar note, I once investigated a fire at a house where a magnifying makeup mirror caught sunlight from a skylight in a bathroom and burned a hole in the vanity countertop. We had a time trying to figure out what happened until I saw the skylight.

So you might try a makeup mirror also for boiling water. If you try it on food it will likely burn a spot in it.

Truik:
The 49-inch circular spot fresnel lens will melt 1/4-inch brown glass in 15 seconds and melt concrete in 30 seconds just by concentrating the sunlight.

That is powerful.

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