Has anybody used a fresnel lens to cook or heat things or start fires? I've just bought a smaller version of one that works great for fire starting.I tried it on the cardboard wrapping.Once I focused the point,I counted,one thousand one one thousand poof the wrapping burst into flames.This lens is page size.Will fit in a backpack with ease.Can be used to heat a pan of water to make soup or heat a tin of beans or w.h.y.I paid $3.09 for it.Going in my bob.
wow, tell us more... where did you get it? is it made of plastic?
I have a 4x fresnel made of plastic, credit card sized.
Here in the desert is good for starting fire (not that is much required).
But is also very useful to get small thorns out.
Is it just the same as a magnifying card? Sounds like it.
It's a 3x page magnifier-8x11.Called ENKAY.Sold at princess auto in surplus part #b8405946.I got mine at ss edm store. there was about a dozen left on wednesday.It is plastic and has the same pattern as a fresnel lens,the circular ridges.I want to try to focus two on the same spot to see what heat 2 would produce.Let me know what you create with them.I think the applications are many.Do you burn the thorns out gerardo? The credit card sized one sounds even more practical for firestarting.Where are they available?
Do you burn the thorns out gerardo? The credit card sized one sounds even more practical for firestarting.Where are they available?
Burn them? No. I scrap them or look at them to pull out.
Is not were I got mine, but I found this http://www.bestglide.com/fresnel_lens_firestarter.html
Mine I just found are supposed to be 5x http://www.bensbackwoods.com/fresnal-lens-magnifier-5x-firestarter-2-pack/
Those big screen projection tvs free off craigslist have three quality glass Fresnel lenses internally and the first plastic screen itself is a Fresnel lense . Yes they start smoking wood or paper in a matter of seconds and I inadvertently started a fire with one so handle and store them very carefully . I should really experiment a little more to see if I can get water boiling in a pot , that sort of thing .
The fresnel lens is plastic behind one or two protective plastic sheets.Everyone (7) I've taken apart has been plastic.A couple have had only one protective sheet.I've since learned that different tv's have different lens with individual properties.I wish I would have kept track of the model of tv to the screen to be able to know the best tv's to get.If you intend to take a few apart keep track of the tv models and the strengths of each lens.I'll probably do 5 or 6 more to find out.If you go to youtube you can see one melting a padlock or a stack of pennies etc.They are now using them to heat pools,heat water pipes in heating systems,cook meals and on and on.A great heat source of the future.
The three glass lens are magnifying lens not fresnel.The fresnel is the flat sheet with the minute ridges.I had read how many ridges there were per inch but forgot.Some ridiculous number for sure.
You may be right Naka, the one I started the fire with was the large plastic sheet about 36 " by 24" (guessing size)
I've been keeping an eye on youtube to see if someone has devised a tracking stand.Until then,it's just playing.
I was doing this a few years ago and ran out of space to work, sidetracked to other stuff. Never did get a solar tracker hooked up. These things are mighty powerful, be careful please.
First incarnation - a pair of TV lenses, focused on a 1.5 inch copper pipe. It's in the back yard now for "UV stability testing". Garage has no space and I made the damn thing too big to fit through any door.
I found a site on youtube called"fresnel lens solar tracker invention#1" by Mr. Teslonian.He used TEG (thermal electric generator) chips to create electricity which goes out through capacitors,charge to a point and release to a stepper motor and adjust the lens.Another of his videos called "fresnel water heater"would be more on the line of what you constructed.He wrote to see-"Alternative energy design group.com" for a factory model.Looks like you and Teslonian are years ahead on this stuff.I'd sure like to see yours operating.Yours looks to be close to completion.Basically the sun, water,a tank and a tracking devise could get yours running.By using it to create steam could you use it to run one of the sterling motors to generate electricity.By creating enough electricity could a large spot light be used to charge the fresnel lens to produce the heat or are there different uv rays or other rays involved here? Basically what I'm trying to say is if a loop could be created where some excess electricity and heat could be taken to heat and light a cabin,all that would be needed is the water to create the steam.Possible source of perpetual heat and light.
Thanks for the great leads Gerardo.There is some other supplies that these companies carry that I could make use of.One thing I've found about Edmonton is that other than basic supplies,it is hard to find the unique things that make backwoods living easier.I guess that is what makes the hunt more interesting.I must admit I have found some unusual things and applications on this forum,all good.
Your average solar tracker isn't going to cut it here, needs to be quite precise to get the lens to focus perfectly. They're fairly easy and cheap to make but the whole system gets complicated.
Steam power is kinda tricky and dangerous. Not something you should leave unattended. Any time you convert energy you have losses, the more conversions the more losses.
A simple solar PV panel and batteries will power LED lights with no fussing about and you have light. Solar water heat is the best way to use the sun, quite efficient and easy to store the heat and move the heat where you want it.
I originally intended to use this as a still to distill ethanol, takes a lot of energy to boil 50 gallons of water to get 5 gallons of ethanol and the sun is free energy.
Alternately, when you have low sun power for a PV panel, like above the arctic circle, you could use these to concentrate the weak sun.