[Stoves] Natural draft TLUD turn-down

Wed May 21 04:01:11 CDT 2014

Kirk
Harris, Paul A and Ron L,

I am not
assuming that the Peko Pe, will pass the ISO IWA low power test as a tier 4
stove, but I find it a bit odd that your method 2, is describing very much how
the Peko Pe used to operate and now operates, including an adjustable primary
air intake.

Robert,
saw the similarity for the lower secondary air inlet in the combustion chamber,
just like the old type of Peko Pe from Uganda in the 1990`s and I noticed the
adjustable inlet for primary air, like in the newest model.

In a micro
gasifier unit, like the Peko Pe, you can also easily “adjust” the amount of fuel to
be used for each cooking.

Just add
fuel to a bit above the bottom plate and your flame will reach the pot, any how,
due to the secondary inlet and the gasification process. 

 A “Rocket”
stove will produce more or less the same thermal efficiency, but with a higher
PM.

These
types of stoves are of course more efficient than a three stone fire, but the
PM is very much the same as any open fire, apart from emissions from a micro gasifier
unit.

It would
help, if a Rocket” stove was lit from the top, but still the strong draft in that
narrow chimney, will create toxic emissions and PM to flow into the (air) room.

I think
you should also look into the Prime cookstoves, invented and patented by Dr. M.
Nurhuda, Professor of Physics, Brawijaya University, Malang, Indonesia, when it
comes to lower and power down the flame.

I guess
he would not be “too happy” to find out that you are calling his PrimeStove –
Wonderwerk…………?

“Your
method” 3, by lifting the char in the combustion chamber, has been declined some
time back, considered to be too complicated. 

We just
put the remaining char into a standard charcoal stove, which you will find all
over the African continent, for further simmering. 

Good
luck with your efforts and tests.It is very much needed, but correct and proper references,
should be mentioned and not “nick named”, that`s all.

Otto 

From: kgharris at sonic.net
To: stoves at lists.bioenergylists.org
Date: Tue, 20 May 2014 11:38:15 -0700
Subject: Re: [Stoves] Natural draft TLUD turn-down

Otto 
and all,

The 
Peko Pe is an incredible stove and the man who created it is even more 
incredible. I wish I had met Paal Wendelbo, but I missed out on that privilege. 
I have met lots of other really incredible people though.

If 
the Peko Pe can pass the ISO IWA low power tests as a tier 4 stove then I will 
agree with you. If not then I will continue my struggles with the Wonderwerk 
test stoves in that direction. When I go to Stove Camp at Aprovecho this summer, 
I want to see a TLUD with low power tier 4 capabilities, be it a Wonderwerk 
stove or someone else’s stove. Come on TLUD folks, we're getting our butts 
kicked by the rocket people here.

Kirk 
Harris
Santa 
Rosa, CA. USA

  ----- Original Message ----- 
  From: 
  Otto Formo 
  To: Stoves Bioenergylist 
  Sent: Monday, May 19, 2014 11:56 PM
  Subject: Re: [Stoves] Natural draft TLUD 
  turn-down

  Dear Roberto,

I very much agree with 
  you.

The Kirk Harris "stove", looks very much familiar and 
  alike the way the Peko Pe has solved this issues and to me it is a REAL 
  wonderwerk, so why call it with a nick name: 
Wonderwerk TLUD 
  ??

This issues can be and are partly solved by the Peko Pe 
  consept - "Problem no", Acoli tribe, Northern Uganda 1994 
  -95.

Otto

  Date: Tue, 20 May 2014 08:38:41 +0900
From: 
  crispinpigott at outlook.com
To: stoves at lists.bioenergylists.org
Subject: 
  Re: [Stoves] Natural draft TLUD turn-down

  Dear 
  Roberto

  I 
  agree with your analysis. There is a lot of merit in keeping the secondary 
  flame in close proximity to the top of the fuel bed. The most important is 
  that the secondary flame is harder to put out with a slight breeze (because it 
  relights). The second is that when the primary air is turned down to control 
  the power, the secondary flame is able to remain hot enough to stay alight. 
  Combined with external, down-drafting secondary air preheating (not like the 
  Peko Pe) one can maintain the secondary air feed ration under different 
  primary air conditions. 

  Read 
  and heed! TLUD's are not succeeding in meeting the turndown ratios required by 
  ordinary cooking. To burn clean at different burn rates, whatever the fuel, 
  you have to control both the primary and secondary air flows. 

  While 
  a 'double controller' can work, turning the secondary air down at exactly the 
  same time as the primary leads to a 2-3 minute period of very high PM and or 
  CO and VOC's because of the retained heat in the fuel bed and stove body. This 
  is worse if the combustion chamber is ceramic or cast iron. 

  If 
  the secondary air feed it an automatic, buoyancy-driven ‎supply, it will draw 
  in additional air as required during the cooling-off period. This explains the 
  strange layout of the air supply in a Vesto Stove which tried to address the 
  problems inherent in David Hancock's (very advanced at the time) 1984 Tsotso 
  Stove (which is still in production). 

  Regards 
  Crispin 
  in Seoul enjoying spring 

  BBM 
  2B567C3

        From: Roberto Poehlmann
        Sent: Tuesday, May 20, 2014 02:28
        To: stoves at lists.bioenergylists.org
        Reply To: Discussion of biomass cooking stoves
        Subject: Re: [Stoves] Natural draft TLUD 
        turn-down

  Kirk,
  this is a very interesting document, thanks to share it.

  The method 2 is like the 12 holes configuration of the Peko Pe design in 
  page 9 of the following document:

  http://www.adansonia-consulting.ch/document/Grass%20Cooker%20handbook_print.pdf?PHPSESSID=3d064accc3efbdafd3b1133a13129f9a

  Maybe this is the reason that the Peko Pe stove don't need an internal 
  chimney to operate. This 12 holes function also like 12 pilot flames, 
  maintaining the secondary flame hot.

  I have replicated this design of the Peko Pe, and in operation, you can 
  see the pilot flames attached to the 12 holes.

  Maybe the 4 holes concept in the middle of the combustion chamber can 
  also helps to maintain a slow power consumption. When the pyrolysis front 
  reach the middle of the combustion chamber, this "primary air" start to 
  combust the charcoal, adding heat to also support the flame.

  Roberto Poehlmann
  Valdivia Chile.

  "All,Dr. Ron Larson, Dr. 
  Paul Anderson and I have been working on the problem of lack of turn-down in 
  natural draft TLUD cook stoves.  We have found considerable success. 
   Attached is a document introducing the results of our labors.  All 
  information is in the public domain.K HarrisSanta Rosa, CA. 
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