Solar Forge via fresnel lens + Organic Matter = TP?

[Tiabin]

Hi guys!
I'm employing what, if google serves me true, seems to be a novel idea... using a fresnel lens to cook up some biochar. Has anyone done anything like this? Any tips? Thus far I'm thinking all I need is a tube of some sort, with a top, thats made of some metal that can take a tremendous amount of heat (these lenses can melt glass), pack it full of pine needles, leaves, coffee grounds, chicken bones, and the like... flip upside down, and focus the lens on it for a while. Will this work?

Oh and another question... I plan on charging the charcoal with my urine. I'm going to be installing an organic garden on the property. It'll be my first garden, and unfortunately our soil has a significant amount of clay. Will the coal + compost be sufficient to repair the tilth of the soil, as well as provide the essential nutrients? From what I'm reading it seems like the charcoal readily replaces fertilizer nearly entirely -- let alone the biochar PLUS compost.

Input is greatly appreciated.

[freeztar]

Originally Posted by Tiabin

Hi guys!
I'm employing what, if google serves me true, seems to be a novel idea... using a fresnel lens to cook up some biochar. Has anyone done anything like this? Any tips? Thus far I'm thinking all I need is a tube of some sort, with a top, thats made of some metal that can take a tremendous amount of heat (these lenses can melt glass), pack it full of pine needles, leaves, coffee grounds, chicken bones, and the like... flip upside down, and focus the lens on it for a while. Will this work?

You'd probably be interested in this thread :
Solar Parabolic Trough Charcoal Oven

It starts off as an experiment to perform pyrolysis with a parabolic trough reflector. About half way through the thread, I and others have attempted to create char using fresnel lenses. So far we haven't come up with an optimal design, so any input is most welcome!

Oh and another question... I plan on charging the charcoal with my urine. I'm going to be installing an organic garden on the property. It'll be my first garden, and unfortunately our soil has a significant amount of clay. Will the coal + compost be sufficient to repair the tilth of the soil, as well as provide the essential nutrients? From what I'm reading it seems like the charcoal readily replaces fertilizer nearly entirely -- let alone the biochar PLUS compost.

The char doesn't replace fertilizers. Actually, it's porosity allows fertilizers to infiltrate the char. Some sources say that because of this you must "charge" the char and/or make sure you add enough fertilizer. Supposedly this is only a problem when the char is first introduced. A way around this seems to be composting. Throw the char in with your compost. You can toss your urine in there as well (don't overdo it).

I also have very clay soils (Georgia). The char helps a little with texture, but I'd recommend adding some sand and crushed granite.

[Tiabin]

Hi freeztar,
I went through most of the thread. I find it seems a little too daunting, unfortunately, for me to take up a task that seemingly a forum full of scientists and the like couldn't get to work out. (Or did it work, and are you guys just obsessing over perfection of design?)

What's the easiest way to accomplish home-made charcoal in a fairly unmessy way? I was thinking of just buying charcoal, but it seems like the pulverization may be a little too intensive for my intended 2k square feet garden.

[freeztar]

Originally Posted by Tiabin

Hi freeztar,
I went through most of the thread. I find it seems a little too daunting, unfortunately, for me to take up a task that seemingly a forum full of scientists and the like couldn't get to work out. (Or did it work, and are you guys just obsessing over perfection of design?)

It hasn't worked so far. I wouldn't let that stop you though. AFAIK, all of us that have worked on this are "backyard scientists". We're not professional researchers with elaborate equipment, just a bunch of enthusiasts trying to experiment with different options. It shouldn't be daunting, but it is sure to be challenging.

What's the easiest way to accomplish home-made charcoal in a fairly unmessy way? I was thinking of just buying charcoal, but it seems like the pulverization may be a little too intensive for my intended 2k square feet garden.

Two threads for this:

Questions for Biochar Makers

How to crush, grind, pulverise charcoal

[Nitack]

Won't let you give up that easy.

Unfortunately circumstances dictated that we were not able to conduct our experiments to the fullest extent. It is not that we could not figure it out, it is that we have yet to discover the proper set up. It will be done!

As of August 25th I will have a suitable testing facility/back yard again and my experiments will resume. My current design will involve the use of an aluminum vessel to hold the char-able material. The ability of Aluminum to conduct heat I think will actually make it possible to get the entire vessel up to the right temp and stay there.

Stick around man... you still have time to get in on something great.

[Tiabin]

Nitack,
Were you the only guy that was experimenting with the fresnel lens originally? The thread was beefy, and it was hard to sort out useful content...

I'm reading that the melting point of aluminum is 1200 degrees fahrenheit..... do you consider that a possible problem? I read that some of the big lens spots can get up to 2000 degrees.

[freeztar]

Originally Posted by Tiabin

Were you the only guy that was experimenting with the fresnel lens originally? The thread was beefy, and it was hard to sort out useful content...

GREENPOWERSCIENCE and myself were also experimenting with this. If you haven't been to the GREEN POWER SCIENCE website yet, I recommend it! For my own experience, I bought some plumbing pipe, painted it black, and stuffed it with leaves and small twigs from my yard. I had a cap on one end and the other end open. The large lens I have (44" iirc) burnt the paint away and I was never able to achieve char, even though the metal was glowing orange (but only in about a 0.5" diameter area). I highly recommend reading the last 15 pages or so as that is where we start discussing different designs.

I'm reading that the melting point of aluminum is 1200 degrees fahrenheit..... do you consider that a possible problem? I read that some of the big lens spots can get up to 2000 degrees.

Ideally, you want to char below this temperature anyways. By unfocusing the beam slightly, you can lessen the heat dramatically.

[Tiabin]

Thanks, guys. I think that pretty much covers my questions regarding the fresnel. Yeah, the greenpowerscience website and videos are great.... and freeztar, I dig the science quote.