Fresnel lens cooker

[kyonu]

So I was just scanning youtube on my daily quest to find cool things, and I found this:



It's a system where someone took apart an old projection TV (you know, the ones you always see chillin by the dumpsters? They're everywhere!) and used the screen, which apparently is a Fresnel lens, and the mirror behind it, to make a Solar Cooker.

There are several videos on Youtube with this same premise--basically, you use the Fresnel lens to focus heat onto the mirror, which reflects the light back to the bottom of the pan as a cook top. Or, you can simply use the lens to project heat onto a medium sized copper flap, which will heat the entire surface, thus you can use one or more cookers on it.

Anyone try this before? Looks like it will be fantastic when camping!

 

[Lucky mike]

its a nice system ...but to haul it around for any duration would get on your nerves...

suggestion using almost the same principle...(actually its the cats butt!)

go to wall mart or a yard sale and pick up a long door mirror...check to make sure it is made from plastic....take it out of the frame...drill a small 1/4 inch hole in each corner...pass a piece of para-chute cord length wise thru the 2 holes with the cord showing on the mirrored side......knot or tie it on one end....

now...pull the cord so you convex the mirror (Banana shape)......aim it into the sun and put your pan above it (a portable campfire grill is perfect to set the pan on)...ajust the mirror to aim the sunbeam at the base of the pot......your cooking fast!!!

do not put your body ....hands...or flammables in the beam unless you want to find out how well this thing focuses the sun energy(your really not gonna like it)

you can cook a grill cheese on a cast iron skillet in about 5 minutes!!!!!
it stores flat or mount it to your side door for some one to talk to at nite!!!!!

PARABOLIC MIRROR COOKING

 

[WheelEstate USA]

That's so groovy. Amazing focus that he could hold a leaf without being cooked.

I'm thinking it might cook too fast. Sizzling and browning doesn't always mean its cooked. Things that need to be stirred might be ok, but would a steak survive the torture for one who doesn't like pink in the middle **gasp**

I love the idea, as with all solar, but its a companion to your solar oven/dutch cooker. Something that I could see as a solar wok for meals and to amaze guests stopping by your camp.

 

[Lucky mike]

another good solar cooker is an innertube and a glass storm window set over the top!!!!

of course I finally just gave in for a store bought collapsible....LOL......why is it when you build a do-it yourselfer some one always sells one alot more functional and smaller than yours!!!

 

[WheelEstate USA]

Yeah Mike, anything solar is fun to try, as long as a person takes a little care.

I've made a cooking cone using a piece of Refletix and an oven bag, and even used the silver inside of empty mylar snack bags. We all messed with magnifying glasses as kids (anyone get in trouble with one??).

A couple years ago I gave Margie and some neighbors a chance to see different methods of camp cooking (mind you, in Arizona). Just outside our shaded patio area, I set up a few simple solar cookers with different cooking vessels (painted jars, brushed stainless pot, cast iron, etc). Under the shade were a couple camp stoves, packpacker, and a couple stick and charcoal grill/cookers.

We had a good time and the neighbors were quite impressed with the simplicity. A few were proudly displaying their own cookers over the next few weekends. it also gave me chance to check out some digital thermometers I had acquired at an estate sale.
Margie, being her childlike self, wanted to touch and ended up sticking her finger in the beer chest several times. Gotta keep an eye on curious minds sometimes

---

another good solar cooker is an innertube and a glass storm window set over the top!!!!

of course I finally just gave in for a store bought collapsible....LOL......why is it when you build a do-it yourselfer some one always sells one alot more functional and smaller than yours!!!

Very true, but its good to add to your knowledge of different methods. Simplicity sometimes wins over all else when its a matter of need.
I'd bet you were excited to see the results of each of your experiments.
You're the "wanna know" kind of guy and have some good info to share.
I'm glad the web has given us a way to exchange ideas so easily

`

 

[Lucky mike]

I find solar setups for cooking , heating and hot water great.....I made a solar hot water heater for my rig and knowing I have a long shower available is heaven.......solar cooking is great because I can set it up and at the end of a long day dinner is ready....its minimal effort to build them and cost nothing to use them !

 

[kyonu]

That's so groovy. Amazing focus that he could hold a leaf without being cooked.

I'm thinking it might cook too fast. Sizzling and browning doesn't always mean its cooked. Things that need to be stirred might be ok, but would a steak survive the torture for one who doesn't like pink in the middle **gasp**

I love the idea, as with all solar, but its a companion to your solar oven/dutch cooker. Something that I could see as a solar wok for meals and to amaze guests stopping by your camp.

In this particular video, you'd be right. I browsed youtube and found this one as well:



They use the mirror to reflect the light upward, directing it to the bottom of the pan. This way it'd be just like on a cook top! This one I was more interested in.

Specifically, devising a structure that folds flat and can be stored easily. But it's an idea!

To that, I was thinking having the lens pointed directly at a large metal surface (probably copper), and have it heat up. This way, you can lay two or so pans on the metal surface, and have it gradually heat the pans (like a stove), that way it's not "direct" sunlight.

But reading the other ideas on this thread at very interesting!

 

[WheelEstate USA]

Gotta love El Sol
Living in the southwest for most of my life, I've learned to work with both its worst conditions and its best attributes...great solar being one of the most valuable as an energy source.
Water is a bit trickier.

 

[christine]

Yes, I've tried it. It was a fun project for a while, but in my opinion it's impractical for van dwelling.

I have a large lens (the small ones aren't powerful enough for cooking, I tried), and I built a frame for it--the lens must be flat in order for it to work. It takes up a lot of space, and it requires both a frame and a stand. I tried not using a stand, but it was a huge pain to have to stand there and hold it still for any length of time.

It's also dangerous. One must be careful not to let any pets or children run around while the thing is out, and keep it covered so that it doesn't accidentally start any grass fires.

Wind is an issue. The lens is like a large sail. A sturdy frame and stand will keep the lens in place, but it's difficult to make a stand that's compact and light enough for travel, but sturdy enough to withstand a little wind.

I was able to cook an egg with it, but some parts of the egg were rubbery, while some parts were undercooked. I'd cook with it more often, but direct sun is required . . . and if it's a sunny day, I find it much easier to plug in my induction cooktop and cook using that.

So, yeah, for me it was novel and fun for a few weeks, but after that it just wasn't practical for long term use.

 

[WheelEstate USA]

Use of solar isn't always easy or convenient for lots of folks, but its a good thing to understand its uses. Never know when you'll need the knowledge.
Some of us who boondock have nothing better to do some days than play with things like this. We know they work, but we have fun with our own variations and ones we've heard about.
Kids whose toys don't say "Hasbro"

 

[sl1966]

This is basically the entire plot to Lemony Snicket's A Series of Unfortunate Events.

 

[highdesertranger]

I have a large Fresnel lens I have experimented with. like others have said be careful if small children or pets are around. the beam is intense. do not put your hand in front of it. it will light tender almost instantly. but you must constantly adjust it for optimal heat. within about ten minutes the sun has moved enough to make it unusable. so if you were to constantly monitor it and have some way to regulate the heat it would be quite useful. just my 2 cents. highdesertranger

 

[Zil]

I'm with Margie on this one. Where is the beer chest.

 

[kyonu]

I have a large Fresnel lens I have experimented with. like others have said be careful if small children or pets are around. the beam is intense. do not put your hand in front of it. it will light tender almost instantly. but you must constantly adjust it for optimal heat. within about ten minutes the sun has moved enough to make it unusable. so if you were to constantly monitor it and have some way to regulate the heat it would be quite useful. just my 2 cents. highdesertranger

On that first video, he has a lens orientator, which basically is two holes drilled on a metal clip which indicates where the sun is. If the light touches the second hole (coming out of the first hole), then it's aligned. Ingenious simplicity!

Also, I am fully aware of the size limitations and camping this hunker. But, it will be fun to try. As I am planning to get a large vehicle, maybe this will be more practical for me. But it's not for everyone!

 

[highdesertranger]

it's not that it's hard to adjust but you have to keep adjusting as the sun moves. also you not only have to align the sun you have to have what ever you are heating in the focal point(distance from the lens). believe my these things convert an incredible amount of energy from the sun into useable heat for free. but it takes allot of user input to keep a steady temp. what it really needs is a tracking system and a thermostat. highdesertranger