Solar Parabolic Trough Charcoal Oven

[rebelcat1]

Thank you for the prompt reply. From my perspective the advantage of angering is that the whole process becomes automated. I'm thinking of a system where you're loading material into the feed hopper with a loader, 1+ cubic yards at a time, with a throughput on the order of 10 to 500 cubic yards per day. Of course any prototype I build will be much smaller, but that's why I want to aim for an auger.

Also, once we get above even a fairly small scale the mechanics of hand loading a tube get very arduous. Other advantages include charcoal will be mostly powdered, especially if starting with material like straw and the larger scale make capture and use of the 'woodgas' or 'syngas' more feasible.

Another idea I had, if you were going to encase the thing in a vacuum tube you could have the top 25* of the pipe covered with some high temp insulation in such a way that it supported the vac. tube, adding to mechanical resiliency.

I still need to read the entire thread (I'm half way through) and more info on reflector design. I saw some really cool looking stuff about Fresnel reflectors, could be lighter and more resource efficient.

rc1

[rebelcat1]

I see another misunderstanding between us- I am talking about pushing the material all the way through and out of the solar collector. The purpose is not to agitate within a closed tube. Does that make sense? If it took say 6 hours to cook the stuff given X amount of radiation striking it than the transit time through the pipe would need to be six hours. For a faster throughput increase pipe length or radiation. I'm thinking about something with a length of around 40 feet and a reflector cross section of around 15 feet.

[Turtle]

Originally Posted by rebelcat1

Thank you for the prompt reply. From my perspective the advantage of angering is that the whole process becomes automated. I'm thinking of a system where you're loading material into the feed hopper with a loader, 1+ cubic yards at a time, with a throughput on the order of 10 to 500 cubic yards per day. Of course any prototype I build will be much smaller, but that's why I want to aim for an auger.

Roger. I was thinking continuous with the auger too, but as I say, I now think there is no gain. Isn't it a work problem as far as physics goes? x amount of wood and y amount of Sun? Then there is the matter of an auger stout enough to move the material, which is going to decrease the volume of wood in the receiver by its displacement. Then there is having to deal with clogs when a knot lodges between the auger and pipe halfway down.

Originally Posted by rebelcat

Also, once we get above even a fairly small scale the mechanics of hand loading a tube get very arduous.

I think a hopper could speed up loading and some sawbucks to hold the cooling/cooled receivers while the charcoal is pushed out. Prolly could come up with a simple machine to drive a plunger to push the stuff out.

Originally Posted by rebelcat

Other advantages include charcoal will be mostly powdered, especially if starting with material like straw and the larger scale make capture and use of the 'woodgas' or 'syngas' more feasible.

Well, maybe. But it seems like you will have to use a lot of power from some source to drive the auger. Maybe the wood-gas itself?

Originally Posted by rebelcat

Another idea I had, if you were going to encase the thing in a vacuum tube you could have the top 25* of the pipe covered with some high temp insulation in such a way that it supported the vac. tube, adding to mechanical resiliency.

The vacuum tube is the insulation. I was thinking about the vacuum/Dewer tube last night though in regard to the gas & steam venting you mentioned, and some special consideration will have to be made so pressure doesn't build. Maybe just havig one end open like the familiar Thermos® bottles would do? Also, for a down-n-dirty vacuum enclosure I was thinking maybe nested fish aquariums or something made of sheet glass so you avoid the expense of having a Dewar tube made by a glassblower.

Originally Posted by rebelcat

I still need to read the entire thread (I'm half way through) and more info on reflector design. I saw some really cool looking stuff about Fresnel reflectors, could be lighter and more resource efficient.

rc1

Roger. One thing on the Fresnels (they are lenses, not reflectors) is that you have to add a drive unit of some kind to keep them focussed. Same with round parabolic reflectors. This is the great advantage of a parabolic trough reflector, it only needs to be set oriented on an East/West line and it works all day. True a trough could be made to track, but unlike the others it will work without tracking. I'll let you finish reading.

[freeztar]

Fresnel Reflectors exist as well as the lenses. It's probably a poor name for them, confusing at least, but there you have it.

Fresnel reflectors - Solar Cooking

[Turtle]

Originally Posted by freeztar

Fresnel Reflectors exist as well as the lenses. It's probably a poor name for them, confusing at least, but there you have it.

Fresnel reflectors - Solar Cooking

You're a sharp one Mr. Freeza. I agree the term Fresnel is misapplied here.

Originally Posted by Dictionary

Fres·nel (fr-nl), Augustin Jean 1788-1827.
French physicist who supported the wave theory of light, investigated polarized light, and developed a compound lens for use in lighthouses.
Fresnel - definition of Fresnel by the Free Online Dictionary, Thesaurus and Encyclopedia.

Dare I suggest "compound parabolic reflector" for these devices?