Simple Solar Cooker

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Introduction: Simple Solar Cooker

About: www.kevinpluck.net
Solar cooking for the worlds poor.*

The aim of this project is to create instructions for a Solar Cooker that can be sent to developing countries. For this to reach the widest population the instructions must be non-language based and that it can be constructed with the barest minimum of tools, materials and skill.

The instructions should be as simple as possible so that they can be easily hand drawn and modified.

The cooker will use the curve of a hanging rope or chain which will be approximatly parabolic. (google catenary if you do not know why) This shouldn't matter as a catenary gets closer and closer to being a parabola the wider you stretch it and we are focusing on a pot, not a point.

The dimensions are important. Using a 4:1 ratio means the focus will be in the middle along the top of the cooker in line with the two ends which makes setting it up really easy. (See step three)

The materials could be anything from corrugated cardboard to plywood with aluminium foil to broken glass for the reflector.

I have not made this at all as I do not have the space (tiny london flat) and the required sunshine.

If someone builds and tests this cooker it would be great to hear about your experience and please make improvements!

I have placed this in the public domain, I want this idea to grow, mature and most importantly be used.

  • <HAL 9000 EDIT>
Or for recreational, less heroic purposes. I, for example, will be taking this with me to Burning Man '07 as a practical, green way of cooking my food. how about cooking hot dogs? you can use this where you may not be allowed to use a barbecue, and it requires no fuel or lighting. Instant heat!

Step 1: Measure Two Boards 4:1

If you can come up with a clearer way to show a 4:1 ratio, do so!

Step 2: Use a Rope, Heavy String or Chain to Trace Curve From Top Corners to Bottom

This really needs to be clearer.

The images needs to portray that you can use any heavy rope or chain and that it goes from one top corner to the other and reach the bottom.

It is also clear that there needs to be extra material for strength along the bottom.

Step 3: Cut Out Curve


Step 4: Attach Boards to a Base of Same Length But Width Can Vary

I've left the attachment method to the ingenuity of the builder as i cannot make any assumptions to what tools or resources the builder will have.

What I don't know how to do is indicate on the diagram that you can have any width to the base. Any Ideas?

Step 5: Cut a Flexible Board of the Same Length As Rope/chain in Step 2.

As mentioned by Hal 9000 you can use the length of the chain/rope in step 2 to measure the length of the reflector. This way your length will turn out perfectly, and you will have no trimming at all once you have mounted it to the cooker base.

An improvement to the diagram would be to draw it slightly curved to show that it is to be flexible.

Step 6: Glue Tin/aluminium Foil or Broken Glass/mirror to Board


Step 7: Attach Flexible Board to Curved Cut Out.


Step 8: Show How to Use

The cooker can be tilted along it's length and rotated so that the sun is always in line with the focus.

(I admit that the main picture of this project makes it look like the cooker remains on it's flat base)

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    39 Discussions

    If you combined the instructable for simple solar cooker with the instructable for a parabolic death ray https://www.instructables.com/id/Parabolic-solar-ray-gun-a.k.a-solar-death-ray/ would that make the heat more direct under the cooking pot? I say these two ideas, and thought, hmmm, I wonder if the parabolic death ray could be used as a solar cooker? Anybody have any ideas?

    I began experimenting with solar cookers with "compound" parabolic dishes this September. I found them to be far better than parabolics for what i did. My cooker gets 3 hours of collection with having to move the dish. I wonder is there an easy way to make the compound parabolic shape? I have now done the dome mold thing I suggested and it works really well. And i made an instructable and have a template for the compound parabolic dishes. Just in case anyone is interested. Brian

    1 reply

    Just a note that I did further testing and the dish I made was not much better than a parabolic dish. A better dish for unattended cooking is clam shaped.

    If you still wanted to show the base can be any distance apart, just draw a line with double arrows pointing along the base with an x on it. X is a variable in math and means whatever number, so it should be applicable.

    very interesting project, seehttp://thoxbui.com/catenaryreflector/home.html and his great simulator(click on link at the bottom of  "Mathematics")

    0
    user
    wrique

    12 years ago

    Rather than gluing aluminum foil to the reflector, consider using aluminum duct tape. It comes in 2" & 3" widths so you'd have to lay down several strips.

    I've use this kind of tape for all kinds of stuff, including covering my custom bike frames & other parts to get an inexpensive chrome-like finish - http://wrique.blogspot.com/2006/01/ice-trikes.htm

    2 replies

    That would work really well and it is the type of ingenuity the builder should incorporate when making this. If you can come up with a generic way to describe applying a reflective surface to something, that can be understood with a simple drawing, so that it does not need to be translated into multiple languages (phew) I'd really like to know! Cool trikes! - although the above link is dead (had to go via your blog - an 'l' missing in the url) - it must feel very strange riding a rear steered trike, it'd feel like over-steer on a normal turn!

    I saw in an old magazine instructions on how to build a smaller version of this ( hot dog Cooker) the part I think would be good here is a focusing device like theirs. It was just a nail or similar mounted square to the axis, with a small disk of something around its base to show a shadow. when there was not a shadow around the nail, it would be perfectly aligned with the sun.

    But that would be a cylindrical reflector that doesn't focus on a single point or line.
    http://www.fossilfreedom.com/increase-output.html
    Even if the drum has a white coating or lining, I would think more reflective surface would perform better. Not that I'm saying one shouldn't give it a try if they have the drum. One drum would make 2 cookers if it works.

    This would be used as the reflector and strong enough to not need a back board. Although you'd probably need something like plywood for strength.

    To clarify: Although you'd probably need to build the whole thing out of something like plywood for strength.

    First, it seems that deep dish parabolic solar cookers are best. Second, it seems that it is hard to make them (though I have made a 4 ft by 4 ft one from cob and it was a good first model). Why not this idea? 1 Design a generic deep dish. Say 4 ft round, Then design a dome that it fits exactly over. Then send instructions for making the dome around the world. The dome might have a hole in it to just below the focal point (to easily mark the point). Build the dome centrally in villages. People can then use the dome as a form for making cardboard, or cob or mud or daub and wattle parabolic bowls! They do not have to completely cover the dome to succeed. No need to make exact cuts either! You make the first radial cuts in the cardboard, you fold the cardboard in and cut and tape to match the parabolic dish. It might be pretty quick! Perhaps try it with the outside of an old satalite dish as the dome? I dont have one.