[Stoves] Fire Stump

Sun Jul 17 05:51:16 CDT 2011

sabes que cuidado que te estas enamorando a distancia, o lo tenias dentro de ti y te salio ahora despues de tantos años, pero es agradable y bonito sentir por alguien, preocuparse, pensar, saber, buscar a alguien, la incognita es como saldra esto con la mujer que se come a los tigres jajajajajajaja  ..david...............

From: rongretlarson at comcast.net 
Sent: Saturday, July 16, 2011 11:50 PM
To: Discussion of biomass cooking stoves 
Subject: Re: [Stoves] Fire Stump

Ron H et al

    Thanks for the additions.  I agree with all your comments.  I would like to study how this might burn with a tiny air hole.  I am surprised it has such a nice flame with only air from the top.   
    The URL didn't work for me, but I eventually got to a video.  It was burning at the outside at 1 hour twenty.

    They also had a "yule" log, which burned horizontally with a different set of "slicings"

Ron L

--------------------------------------------------------------------------------
From: "Ronald Hongsermeier" <rwhongser at web.de>
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Saturday, July 16, 2011 8:56:09 PM
Subject: Re: [Stoves] Fire Stump

Dear Ron,

I was going to reply to your questions internally, but for some reason-- probably that you used html to answer-- the paragraph marking on the left won't break for it to be clear what I am writing and what you wrote. For your first question. I think that it is obvious from observation that the vid referenced by Jeff Davis is made with either 3 or 6 plunge cuts in the end of the log.(period). What allows it to burn so long is that it is O2 limited/regulated by the slits and by the air only coming from the top.

When you go to a full partial wedge cut, you loose quite a bit of radiant energy and the amount increases rapidly with the length of burn time.

The version with the 2 relatively large holes (rocket-like) could be made a near tlud if at least part of the long hole was conically reduced toward the bottom and the "rocket" hole was radically reduced in size _or_ given some kind of simple valve/control.

Your observation about the char production is probably right. No one method does everything.

The easiest way to make the big holes would be with an appropriately dimensioned lathe.

regards,
Ron
w
h

------------------------------------------------------------------------------
  Von: rongretlarson at comcast.net
  Gesendet: Jul 17, 2011 1:22:11 AM
  An: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
  Betreff: Re: [Stoves] Fire Stump

  p { margin: 0; } 
  Rob:

     Thanks for sharing these additions.   Does anyone know if the unit first given by Jeff Davis had a "Rocket" design (horizontal hole) for air or whether the central hole might go all the way through to the bottom?

     I think these  (both central hole and splits) could make for an interesting classroom demonstration.  The points to make are

      1.   that the energy from the flame anywhere is mostly captured.and used to keep the flame going on opposite surfaces.  For the rocket shape, almost no radiant energy is lost.  For the wedges, little is lost.  None. of the narratives I watched (and there are a lot more than Rob has given) talked about the importance of radiant energy cappture.  It would be fairly easy to pull the wedges apart in steps - and at some separation the flames would go out.- showing the importance of capturing this radiant energy.

       "Stumps" of different lengths but otherwise the same could show the chimney effect nicely.  Might be able to control power level with a lower plug.

      2.  In the Rocket (central hole design) it would have been good to have someone show flame control by partially closing the lower air supply.  Might be able to find a way to relate air hole size (and air volume) to power level

     3.  It would be interesting to see if a TLUD design could be operated with a set of secondary air holes part way up.   I don't think so - since the pyrolysis front drops to the bottom almost immediately.  Then the combustion will mostly occur at the bottom.   I think it would be almost impossible to make char with this design.

     4.  There are sawdust stoves (sometimes called Boy Scout??) that operate similarly (to the central hole design).  Dr. Priya Karve did some nice theoretical/experimental work on such.

     5.  No one talked about the great efficiency of the Kelly Kettle - because the flame is going up the center.

     6.  I wish I had seen how difficult it was to drill the central hole of the Rocket design.  Is there a power tool on the market like the chain saw (but for drilling holes)?

     7.  This is way off topic - but there was great long video dubbing a 1930 film of logging at:

  http://www.youtube.com/watch?v=cIKCjQdxtO0&feature=related

  Ron
  _____________________

  From: "Rok Oblak" <rok.stoves at gmail.com>
  To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
  Sent: Saturday, July 16, 2011 12:27:22 PM
  Subject: Re: [Stoves] Fire Stump

  Here are Siberian, Finnish and Swedish and supposedly a Canadian version!  No stove needed!

  http://www.youtube.com/watch?v=gMLzY48YwEM&feature=related
  http://www.youtube.com/watch?v=jOAejiwCIpg&feature=related
  http://www.youtube.com/watch?v=wEHSJftQ9Vg&feature=related
  http://www.youtube.com/watch?v=ndcXILxxy_0&feature=related

  On Fri, Jul 15, 2011 at 10:19 PM, Richard Stanley <rstanley at legacyfound.org> wrote:

    Jeff,

    Clever stuff: Someone obviously  made three intersecting plunge cuts through the center long axis of the stump,  in a 6-sided star pattern. This effectively has turned a fuelwood log into a hollow core briquette !

    Would like to
    1) compare its burn performance: heat curve emissions time to ignite, time to heat xkgs of water to boiling etc,
    ..... as compared to same log, ex these star cuts.
    2) pursue same star pattern molded into an agro residue briquette.

    Richard Stanley
    www.legacyfound.org
    NW Obamaland.

    On Jul 15, 2011, at 7:23 PM, Jeff Davis wrote:

    > Dear List,
    >
    > The odd things one can find when shopping for nuts:
    >
    > <http://www.ecoforestfirewood.com/eco-forest/light-n-go-tm-bonfire-log/>
    >
    >
    > Truly stumped,
    >
    >
    > Jeff
    >
    >
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