[Stoves] "Young-adult" TLUD research Re: List of woods for TLUDs?

Sat Apr 29 22:33:39 CDT 2017

Ron,

I disagree.   You wrote:
> preferring to use one controller for both is that the ratio of primary 
> to secondary should always be the same 
The point is that the ratio is NOT to always be the same.   Even the 
different packing of the fuel in to the TLUD can make primary air (PA) 
flow more easily, creating more gases and needing a change in secondary 
air (SA) to get optimal performance.

Automobiles have sensors for all kinds of issues, with automated 
adjustments.   Just not practical yet for cookstoves that need to be 
inexpensive.  Bu who knows, someday solid biomass as initial fuel could 
be pyrolyzed and have the gases combusted in very controlled ways that 
would seem like Science Fiction if said today.  I believe that it will 
be justified for the woodgas/TLUD stoves, but not for the old-hat ICS 
stoves, including rockets.

Nathan Puffer''s work was not quantitatively evaluated.   It was a 
demonstration that made its point but was not in a way that could be 
into large numbers of stoves at that time and still today.

Paul

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

On 4/29/2017 9:46 PM, Ronal W. Larson wrote:
> Paul,  cc Nathan and list
>
> Thanks for bringing up the two subjects of a)  separately controlling 
> secondary air, and b) oily (mostly seed?)  fuels.
>
> I agree that we should be controlling secondary air, but I am pretty 
> sure that we should and can do this with the same controller as for 
> the primary air.  Most TLUDs already can and should control primary 
> air, but make no effort to control the secondary air.   My reason for 
> preferring to use one controller for both is that the ratio of primary 
> to secondary should always be the same if we want (or can live with) a 
> fixed ratio for excess air.   One controller is cheaper and is easier 
> for the cook.   Anyone disagree?
>
> On the subject of using Jaropha seeds,  I am pretty sure that we would 
> need a larger amount of “secondary” air than for non-oily fuels, but 
> that there still could be a single air controller (just with a larger 
> SA/PA ratio  [ maybe goes from about 6:1 up to 7:1 ??].  Note that 
> these oils cannot combust as they pass through the hot charcoal above 
> the downward moving pyrolysis front (no oxygen in that stream).  But I 
> presume the temperature is enough for them to arrive above the char as 
> quite a different set of gases.  So,  I’d like to hear more about what 
> Nathan found.  Any cite we can look up?
>
> I agree with the rest of Paul’s comments.  TLUDs are not yet a mature 
> technology - but it is growing up;  it is not standing still.
>
> Ron
>
>
>> On Apr 29, 2017, at 8:14 AM, Paul Anderson <psanders at ilstu.edu 
>> <mailto:psanders at ilstu.edu>> wrote:
>>
>> To all,                   29 April 2017     [This note contains some 
>> new content and explanations for the advancement of TLUD stoves.]
>>
>> 1.  Ron:    I and probably some others have successfully used dung as 
>> the input fuel into TLUDs.    I am not recommending dung, but if it 
>> is being burned, then a TLUD is preferred for cleaner burning.
>>
>> 2.  AD:   I agree with Ron that the TLUD stoves are better with both 
>> light and hard (heavy) wood than direct burning of them in any 
>> direct-burning (ICS) stove.
>>
>> 3.  Main point, to Neil and all:   TLUDs are not burning wood 
>> directly.   TLUDs turn wood into gases.   THEN the gases are 
>> burned.   So poplar, maple, maize cobs, dung, etc. are ALL becoming 
>> gases first.   THEN the burning of those gases might be somewhat 
>> different (but not as much as the direct burning of those diverse 
>> fuels).
>>
>> TLUD stoves are just arriving into their "young-adult stage."   In 
>> contrast:  not infancy, not childhood, maybe still "youth", but 
>> certainly not full maturity, and a long way from  the "old age" of 
>> the ICS "Inproved or Inadequate" direct-burning cookstoves.  This is 
>> because we are still learning about better and better ways of mixing 
>> the combustible gases with  the incoming secondary air (SA)  (This is 
>> where the BURNING takes place to make the heat that goes to the pot.  
>> TLUDs are DIRECTLY burning GASES, not solid fuels. )    (Please see 
>> my "Classification of Stove Technology and Fuels" documents (1-page 
>> and 4-page versions) at 
>> http://www.drtlud.com/2017/04/11/classification-stove-technologies-fuels/ 
>> )
>>
>> The _solid _wood and dung etc are an intermediate stage of the 
>> fuel.   Sort of a "storage" stage.  Then pyrolysis "transforms solids 
>> into gases plus charcoal".  The created gases are then burned 
>> SEPARATELY (by centimeters and seconds, but certainly separately) 
>> from where the gases were created.  We do not have clear terminology 
>> for this, in layman's terms.  The closest might be "gas burning 
>> stoves that make their own gases."
>>
>> So, what development is happening in the early "young-adult" stage?  
>> Control of primary air, learning about solid "intermediate" fuels, 
>> and improving combustion of the gases, as well as "new clothes" with 
>> sizes and mateials.
>>
>> Consider this:  We have known of FA (forced air or fan assisted) TLUD 
>> stoves from the 1990s.  And there has been much progress.  But NO 
>> TLUD on the market has SEPARATE controls for "variable flows" of 
>> primary air (PA) and secondary air (SA).   THAT control is what will 
>> make the difference regarding Neil's initial question that pointed to 
>> differences in the initial fuels (and therefore differences in the 
>> resultant gases and quantities of gases that are being burned.)
>>
>> Note that TLUDs can be made with different flows of PA ans SA by 
>> changing the sizes and number of holes.  That is a form of "tuning" 
>> the TLUD for a specific fuel.   This works great for one initial 
>> fuel, but only good but acceptable with other fringe fuels.  I am NOT 
>> referring to that work as being "variable flows".   I am referring to 
>> when the user can change the flows, even during one batch of fuel.
>>
>> There has been some researach (mostly unreported and set aside) on 
>> variable control of primary and secondary air, using fans.  I have 
>> experimented several times.  The "million-dollar-grants" have had 
>> laboratory equipment with controlled and measured separate air 
>> flows.  Nathan Puffer did it when we were looking at Jatropha SEEDS 
>> as a fuel. Seeds give off additional gases from the vaporization (not 
>> pyrolysis) of combustible vegetable oils (carbohydrates), which are 
>> much more plentiful in seeds than in stems and branches and leaves, 
>> thereby overwhelming the insufficient supply of SA in a "regular" 
>> TLUD-FA.
>>
>> There is a good reason to not have separate control of PA and SA.   
>> That reason is the user, the cook.  To need to "dial-in" the right 
>> flow of SA (assuming PA flow stays the same) is, for the most part 
>> and for most non-scientist cooks, an extra task that could easily be 
>> done incorrectly.  And there are the financial reasons of increased 
>> cost and maintenance.
>>
>> But with "separate air-flow control" (not an established term and NOT 
>> justifying an acronym like SAC, as in TLUD-SAC), Neil or anyone could 
>> put many very different initial fuels into a TLUD and have greater 
>> control of the burning of the gases.
>>
>> More work is needed before TLUD stoves can reach their full 
>> potential, while growing in "young-adulthood".  Today (2017), maybe 
>> 40% of what can be known about TLUD stoves is now known (but not 
>> necessarily put into practice by stove manufacturers).
>>
>> (This note is being placed at the EPosts section of my website 
>> www.drtlud.com   so that it can  be accessed continually instead of 
>> only one time on the Stove Listserv.)
>>
>> Paul
>> Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
>> Email:psanders at ilstu.edu
>> Skype:   paultlud    Phone: +1-309-452-7072
>> Website:www.drtlud.com
>>
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