[Stoves] Misconceptions about TLUD origins and operations-- was Re: biochar rocket stove

[Paul Anderson]

Dear Crispin and all,

First, the quote:

> Designed by Paul Anderson, the top light upward draught (tlud) 
> gasifying cook stove works o

This statement can be correct if referring to a specific TLUD stove that 
I designed, which I think is the case of the author who is quoted.    
However, it should NOT be taken that I originated the TLUD stoves.    
The originators are Thomas Reed and Paal Wendelbo, working independently 
in the 1980s and 1990s.   Note that we do not credit the Norwegian 
resistance fighters who influenced Wendelbo as originators of TLUD 
stoves.   Those men were doing top-lighting of open fires, that is, 
fires that were NOT contained inside the walls of stoves.  We needed 
Wendelbo to accomplish that!!!

Second, Crispin wrote:
> The TLUD was invented centuries ago as a way to burning with little 
> smoke. The Romans used TLUD fires. 

Until Crispin or others can produce hard evidence to support such a 
statement, please consider the above to be utterly false and should NOT 
be quoted.

Crispin, let's have the documentation or a retraction or at least stop 
writing such nonsense.   Maybe the Romans did.  Maybe cavemen did.   But 
no proof, no credit.    Forty years ago I observed a "TLUD-like" fire in 
the top of a burn barrel on an windless day. But I did not understand 
it, and I did not develop the concept/technique, and I do not take any 
credit for the original work about TLUDs.   If some Roman or caveman 
ignited some pile of brush or wood on the top, that does not constitute 
inventing TLUD gasifier cookstoves.

By the way, I did coin the term "top-lit updraft" and the acronym "TLUD" 
   back in 2004 and 2005 respectively, but that is not the same as 
originating it or initially identifying it.   Wendelbo had no name for 
what was happening.  (Peko Pe is the stove name.) And Tom Reed called it 
"inverted down-draft" or IDD, which actually it is not, because 
down-draft gasifiers have their hot zones at the bottom all of the 
time.   Actually, with hindsight, I should have called it something 
like  "Top-Lit, Downward Migrating Pyrolysis Zone" (maybe " TLDMPZ") 
because the MIGRATING PYROLYSIS FRONT is by far the most distinctive 
feature of TLUD gasifiers. The real important feature is that the hot 
spot does not stay in one position, but migrates downward.   In that way 
it is unlike any other up-draft or down-draft or cross-draft gasifiers, 
in which the fuel moves and the hot spot stays in one position (which is 
at the bottom on up-draft AND down-draft gasifiers.)

I hope this helps clarify some of the background about TLUD stoves.

Paul

Paul S. Anderson, PhD  aka "Dr TLUD"
Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
Website:  www.drtlud.com

On 9/18/2012 11:24 AM, Crispin Pemberton-Pigott wrote:
>
> Dear Steve
>
> That was an interesting excursion. To be brief, there are a great 
> number of technical misconceptions contained in the document 
> http://www.soil-carbon-regeneration.co.uk/biochar/wp-content/uploads/2012/05/Biochar-Rocket-Stove-building-instructions.pdf 
> so my advice is to try to gain some knowledge from the general 
> approach and from the unusual layout of the product but not take it 
> all as literally true.
>
> It is interesting that anything with a side feed is being termed a 
> Rocket Stove. That rather undermines the actual Rocket Stove as a 
> unique design, in my view. I guess people will call it what they want.
>
> I have copied here a paragraph from a the document:
>
> *The tlud*
>
> Designed by Paul Anderson, the top light upward draught (tlud) 
> gasifying cook stove works on more than just one level. It is a very 
> efficient cook stove, producing a lot of heat from a small amount of 
> wood. It is smokeless and it produces biochar. Paul Anderson has also 
> been instrumental in getting these stoves distributed and used in 
> developing countries where wood or charcoal is otherwise used in 
> conventional fires for cooking. By being more efficient, less wood is 
> needed. By being smokeless, diseases and deaths caused by smoke in 
> living spaces are reduced. By producing biochar, subsistence growers 
> are able to [maintain] soil fertility and improve soil structure, 
> biological activity and moisture holding capacity. Atmospheric carbon 
> is also being sequestered by the use of these stoves.
>
> So, I have some issues with some of this and because the whole list 
> was referred to it there is merit in correcting some of the 
> impressions given.
>
> The TLUD was invented centuries ago as a way to burning with little 
> smoke. The Romans used TLUD fires. A TLUD cooking stove may or may not 
> be 'efficient' depending entirely on how well it transfers heat from 
> the flame to the pot and whether or not the remaining char( if any) is 
> counted as 'consumed by the stove' or not.
>
> The heat produced by a TLUD is no greater than the heat released by 
> burning the same amount of fuel to the same extent in any other stove. 
> That is, if you gasify wood in some other device the heat is exactly 
> the same. TLUD's are renowned for making lots of smoke when things are 
> not working properly, like in the beginning and at the end of a burn 
> there can be lots of smoke. Mitigation of this involves timely 
> intervention by the cook. They are, after all, smoke producing devices 
> that then burn the smoke.
>
> You have no doubt seen Paul Anderson throwing a lit match into a smoke 
> bomb of a stove re-lighting the fire when it has blown out. I have 
> done it myself dozens of times. When they are running well, especially 
> during the main part of the burn, they are amazingly smokeless, like 
> any other really good biomass stove. I hope that the products evolve 
> to the extent that they really are smokeless.
>
>

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