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Charcoal has been used for fuel for millenia. Produced by heating wood in the absence of oxygen, it is nearly pure carbon, without the water or volatiles that cause smoky,uneven combustion in wood. As currently done, charcoal production is wasteful, burning some charcoal to produce more. Many operations
also pollute heavily, discharging the tar and turpentine distilled from the wood into the air.
The Solar Charcoal Distiller allows you to make your own charcoal at home, without bathing your neighbors in clouds of turpentine. The SCD kit (from BUNGCO!) comes with a large plastic Fresnel lens and a special top designed to fit on a standard Weber Kettle. Simply load your Weber with branches and sticks from your neighborhood, put on the special lid, close those air intakes at the bottom, and set up the Fresnel to bathe your grill in concentrated rays (you will want to remove the wooden handles first). Already painted black with heat resistant paint, it will only be a few moments before your kettle glows cheery red and your wood begins to cook. Cook it all day, and then when the sun gets low you will have a kettle full of warm charcoal, ready for grilling dinner!
The special lid is fitted with a metal hose on the top. Place the end of this hose in a bucket of water. Operating on the same principle as a hookah, the steam and volatiles cooked off the wood are cooled and left in the water, for you to use later as you see fit. In our test runs here at BUNGCO we used a lot of eucalyptus and pine - the distilled products proved excellent for treating the bottom of the BUNGCO yacht!
Homemade solar charcoal
http://www.youtube....watch?v=8Makaciz3Xc Giant lens - check. Backyard - check. [bungston, Jul 01 2013]
[link]
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Have you built one? There are dozens of third world countries that could use this. |
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Is there a mechanism to track the sun's movement? otherwise the lens will only be focusing on the kettle for a brief period of time. |
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Fresnel lenses work without tracking. |
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You would need a very big one to make enough heat but
this is an excellent idea! |
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Could you use something like this to convert waste paper and cardboard to a useable fuel? |
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In theory, any cellulosic material could be converted to charcoal. I suspect that anareobically decomposing landfills contain peatlike or coallike substances which could be used as fuel. I do not know the intricacies of charcoal manufacture well enough to understand why some woods and other materials are preferred. |
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out of curiosity Lt, how are you going to track the sun for your fresnel lenses? |
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Mouse-coal, mole-cole, duck coal, whatever the cats drag home. |
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It might be better to have a pyrex glass top for the grill to avoid losing all the heat radiating off the top. The glass top would allow the heat to get right to the wood and reflect back some of the radiated heat. |
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BTW Fresnel lenses do need tracking. |
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So how does this process avoid venting the evolved gasses into the air? |
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Incidentally, those gasses are flammable. It's pretty straightfoward to use them to contribute to the conversion. Indeed, I think if it's set up right, the process can be self-sustaining. That is, you can potentially add wood and remove charcoal in a continuous process, once it's going.
Of course, that would make the idea somewhat superfluous. |
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I realize I'm a few years late, but Fresnel lenses
definitely do need tracking. They are functionally no
different than simple convex lenses, and the focal
point will move opposite the sun. |
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I like the idea of cooking the wood with its own wood gas. I wonder if there is enough energy there. |
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Avoid venting: bubble thru water. Gases should be water vapor and wood alcohols - no CO2 or CH4. So everything should condense and stay in the bucket. |
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I think you get carbon monoxide, hydrogen and methane[1], in somewhat variable proportions. None of these will be caught by bubbling through reasonable volumes of water, and none of these do you want to vent in the vicinity of hot stuff. Apart from that risk of explosion, carbon monoxide is a fairly potent poison. |
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[1] Plus various other minor components, and also other stuff which doesn't burn - in particular nitrogen and carbon dioxide. |
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I like the old-fashioned way of making charcoal. Easier, and has fewer volatiles remaining. |
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Start something on fire. Bury it. Dig up charcoal a while later. |
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They do this in villages around the world. |
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I like the old-fashioned way of making charcoal. Easier, and has fewer volatiles remaining. |
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Start something on fire. Bury it. Dig up charcoal a while later. |
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It does take a certain amount of judgement regarding how much it has to be on fire to start with- to much and you waste wood, too little and you don't convert it all. |
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They do this in villages around the world. |
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I got the strangest feeling of deja vu just then... |
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Horizontally oriented trough reflectors don't require
active tracking. Make your pressure chamber a long
horizontal pipe, with compound parabolic reflectors
behind it. |
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Then when each charge load is cooked, you can open
up both ends and shove new wood and waste in one
end, pushing the charcoal out the other. |
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The gases driven off are known as woodgas, on which
there is substantial existing work in using it as a fuel,
dating back to WWII and before. |
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15 years past, and I am still digging it. |
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// Start something on fire. Bury it. // |
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"Build a man a fire and he'll be warm for a day. Set a man on fire and he'll be warm for the rest of his life... " (Pterry Pratchett) |
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That's great to hear, [bungston]. Do you have any
photos of your setup that you could link for us? |
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