[Stoves] Stove ID please - 2-pot stoves - testing needed

Tue Jan 1 13:32:55 CST 2013

Paul and others if you were having trouble with Gustavo's sketch up images of the 2 pot stove Goolge Sketch up is available for free thru downloads at www.cnet.comoc 

Michael
Majuor
  ----- Original Message ----- 
  From: Paul Anderson 
  To: Discussion of biomass cooking stoves 
  Sent: Monday, December 31, 2012 11:26 AM
  Subject: Re: [Stoves] Stove ID please - 2-pot stoves - testing needed

  Crispin and all,

  The Prakti 2-pot unit should be directly compared with the 2-pot unit from Envirofit.

  http://www.envirofit.org/products/?sub=cookstoves&pid=5    (to see a photo).

    Double-Pot Attachment
    Features
      a.. The Double pot accessory with chimney is the perfect add-on for customers who want the portability and ease of using the single-pot stove, but need the extra cooking area for large families, festivals, or cooking for visitors. 
      b.. The attachment is easily moved onto or off of the stove for quick change ability but is steady and sturdy while attached. 
      c.. The chimney portion can be used as is - to move any minimal emissions out of the face of the person cooking - or can be vented out of the home. * Shown with G-3300 cookstove. 
  And I am sure that there are other 2-pot stoves, but just not being stamped out and with such smooth edges.   Many of us have made such units.

  What is needed is some serious study of these useful features, whether built into the stove or as an attachment.   Issues to be studied include:
  heat transfer to EACH pot
  types of pots used (sit on top or inserted)
  insulation 
  temperatures of the outside surfaces
  fuel efficiencies attributed to the second pot

  And of course, the ways of supplying heat to the 2-pot stove structure.   The fact that both the Prakti and Envirofit units use Rocket combustion structures does not exclude use with other combustors, such as
  TLUDs and even fossil-fuel burners.

  Important note:  These 2-pot structures both (virtually all of them?) have a chimney because horizontal flow of the hot gases must eventually have some upward movement to maintain the draft (exceptions if there are fans in use).   For the TLUD combustors, the chimney is a nice enhancement of the draft.

  I did not understand Crispin's comment about keeping the smoke and flames together.

    It seems to me to be worth investigation the % of smoke that can be burned by keeping the smoke and flames together for a while. 
  That is true for "stick-burners" like the Rockets.   But TLUDs are "gas-burners" (that make their own gases in the close-coupled gasifier reactors.)   What would be the best ways to get the best results with Rockets, TLUDs, or other heat sources?

  Regardless, this seems like a great topic for some research by the now "product-independent" laboratories for stove testing, such as CREEC and Zamorano and ARC.   But the question is:   who will pay for these tests, and who will release the results?   Past practices have been that "he who pays decides what will be released."   And the chances of having both PRAKTI and Envirofit pay and allow comparisons are about slim to none.

  And I am not going to pay for it.   And the testing centers get paid nothing for testing unless there are sponsors.

  So, I hope that the GACC will soon finance some comparative testings of stove STRUCTURES that are not just focused on the combustion devices.   AND then do some testing of those same STRUCTURES but with different systems of combustion, such as having Champion or Mwoto or Quad TLUDs under identical 2-pot structures..

  Happy New Year to all!!!

  Paul

Paul S. Anderson, PhD  aka "Dr TLUD"
Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
Website:  www.drtlud.comOn 12/30/2012 4:24 PM, Crispin Pemberton-Pigott wrote:

    Dear Richard in NW Obamaland

    Agreed. I was looking at the size of the opening at the top and wondering how it burned. I have been working on the use of flame tubes a-la-BLDD6 and earlier versions where the fire is enclosed in a fairly small round channel.

    A couple of weeks ago I tried installing a 57mm I.D. flame tube in a horizontal draft two-pot stove (I will add pictures later) to see if the smoke could be burned post-pot-1. It worked pretty well. I do not yet have definitive numbers but as a design approach it definitely worked. There are a number of stoves that have far too much space after the fire, allowing the smoke and flames to take separate routs to the outlet.

    So the stove in question has a huge outlet so if smoke manages to get to a corner, it has ample space to escape to the margins away from Pot 2. It seems to me to be worth investigation the % of smoke that can be burned by keeping the smoke and flames together for a while. There are several stoves with a suitable layout for this. One is the three-pot stove used in Indonesia consisting of separate clay round sections with interconnecting tunnels. If the tunnels were reduced in diameter to the point at which they became an impediment to gas flow, that would maximise the chance of burning the smoke. If the flame was entering the tube in the simple experiment I conducted, the smoke was dramatically reduced showing a reproducible and consistent effect.

    I really like the cast iron grate in the Prakti stove with a thickened front bar that will resist banging from heavy wood sitting on it.

    Regards

    Crispin

    Crispin,

    This seems to be c similar o what was coming from the Dutch TOOL foundation in (A ' dam)  in the late 70's. They were trying to replicate them thru our center (AATP) during that time but it never really took on. 

    Richard Stanley

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