[Stoves] Lower PM in TLUDs than in stoves with fans

[Dean Still]

Dear Paul,

You may have noticed that the TLUD featured in Jim's talk yesterday did not
do so well. I hope that the TLUD community can help to tune up TLUDs so
quality stays high.

There are bad Rockets and good ones. The devil is in the details, as they
say. More bad ones than good ones, unfortunately.

As Crispin points out, there are also good and bad stoves that use forced
air.

I think we need design principles for TLUDs so folks can know how to make
high performance TLUDs but we're not there yet as far as I know.

All Best,

Dean


On Thu, Aug 29, 2013 at 6:35 PM, Paul Anderson <psanders at ilstu.edu> wrote:

>  Stovers,       (and sent to my www.drtlud.com   Webmaster who can place
> this on my website, but comments will be answered via the Stoves Listserv.)
>
> On 8/28/2013 10:56 PM, Dean Still wrote:
>
> ......
>
>  Jim Jetter reports that a TLUD can have fewer fine particles compared to
> fan stoves. We're finding the same thing.
>
>   It is time to get serious about how TLUD stoves have superior
> performance.   Finally we are getting lab testing data.   Well, not
> really.   We are getting "statements" but the data sets are not being
> presented to us.   That is okay.   We can wait for Dean and Jim and ALL
> OTHER STOVE TESTING CENTERS to provide some data.   Let's just use the
> above statement as the basis for my comments here.
>
> 1.  "Fan stoves" is a BAD name.   Any stove with a fan can be a "fan
> stove".   What Jim and Dean are discussing are stoves that include Oorja,
> Biolite (two models?), Philips, Reed Woodgas Campstove, maybe some units
> from China.   At least THREE different combustion regimes are included in
> the above named stoves.   But Who knows which ones they are talking
> about?   THEY know, but protocols etc are preventing the data results from
> being given, even with or without the names of which stoves.   But we do
> know that they have fans.   But so do some other stoves.
>
> 2.  "Stoves with fans" is also not sufficiently specific, but at least
> they could be recognized for what they are, which is, stoves of different
> types that have fans.
>
> A.  They could be "Rocket stoves with fans" as in the Biolite Home stove
> and maybe something (prototypes perhaps?) from Envirofit or Stove Tec.
>
> B.  They could be "Fan-jet stoves with fans" (or some other name, but this
> is what I have called them for several years).   These are stoves with
> intense, forceful mixing of air deep into the fuel chamber.   These include
> the Biolite Campstove, Philips stove, the WorldStove Lucia-FA (forced air),
> and the Turbococina of El Salvador.   These are (perhaps) related to
> pellet-stoves as sold in North America in which the intensity of the jets
> of air consume small quantities of pellet fuels in a small cup-type
> combustion chamber.   For sure these are NOT TLUD stoves.  They can well be
> micro-gasifier stoves.   They can certainly be highly regarded.   But they
> are not the only stoves with fans.   And to call them "fan stoves" is
> unclear and unfair to the other types of stoves that can have fans.
>
> C.  They could be "Simple Improved Cookstoves - ICS - with fans".
> Something like a bucket-stove with a fan blowing onto the flaming fuel.
> No examples come to mind, but add a fan and have a "fan stove."
>
> D.  They could be "TLUD stoves with fans".   Yes, TLUD stoves can be
> operated with fans.   The opening statement is referring to natural draft
> TLUD-ND having less  PM than TLUD-FA.     TLUD-FA stoves include the Reed
> Woodgas Campstove, the Oorja stove, the Belonio/Olivier rice husk
> gasifiers, McLaughlin's Joy-to-the-World, and my 2004 prototype "Juntos B"
> (which is described in the 2004 paper   "Biomass Gasification: Clean
> Residential Stoves, Commercial Power Generation, and Global Impacts
> (available at
> http://www.drtlud.com/resources/publications-and-multimedia/psa-catalogue/
> ).   And there are probably other TLUD-FA units.
>
> 3.  So, one study that needs to be done is to compare the PM from TLUD-ND
> and TLUD-FA.   Do such results already exist?    Do we need to wait very
> long for these results?   I ask these questions to those who have the
> capabilities and the financial resources to conduct those tests.    You
> know who you are.   Ongoing budgets and some major grants have been given
> for capabilities to conduct these types of tests.   And it is not just EPA
> and Aprovecho who get such funding.   But some grants prevent the
> dissemination of results until much later.
>
> 4.  BUT.   Yes, there is a BIG BUT to be considered.   This is because
> TLUD-FA (those with fans) have been blatantly mis-used and the test results
> could be erroneous because the test was not stopped when the TLUD pyrolysis
> process stopped, which is when the bottom burning of char started and
> continued as long as operators were feeding in raw fuel at the top.
>
> I repeat:  the TLUD testing needs to be *stopped when the TLUD pyrolysis
> process stopped, which is when the bottom burning of char started and
> continued as long as operators were feeding in raw fuel at the top.  *
>
> [[   I have already prepared a short document about this and will post it
> soon. ]]
>
> In conclusion, let's get our understanding clear that the addition of a
> fan to a stove does NOT automatically put that stove into the Tier 3 and
> Tier 4 categories of low PM emissions.   FIRST think of what kind of
> combustion the stove utilizes:   simple ICS, Rocket, TLUD, other
> micro-gasification, other ....    THEN consider if it has a fan in it.
>
> In biology, first the animal type, and then if it flies or not:   Birds
> fly (but not all of them);   Many insects fly;   some pre-historic reptiles
> could fly;   and some mammals (bats) can fly.   Flying is important, but
> Phyla is more important.   Fans are important, but not more important than
> the combustion regime.
>
> STATEMENT:  I believe that the TLUD stoves (whether ND or FA) are cleaner
> about PM than the other combustion regimes because the process of pyrolysis
> leaves the inert materials (non-combustibles known as ash) held tightly to
> the charcoal that is created.   So, do NOT burn the charcoal.   Especially
> do not burn it with vigorous streams of air at the level of the charcoal.
> [And there are probably additional variables to be studied.]
>
> This hypothesis remains to be proven.   But while we wait for the test
> results, money will be channeled to other stove technologies, field tests
> of health will be conducted withOUT having a TLUD stove included in the
> study, and people will continue to suffer (and some will die) because of
> the high PM levels in household cookstoves.  It is late 2013 and studies of
> TLUD stoves are only scratching the surface of what things need to be
> studied.
>
> Oh well, better this progress than less progress.   And all of the TLUD
> enthusiasts are certainly willing and eager to join into any and all
> efforts.
>
> Paul
>
> Paul S. Anderson, PhD  aka "Dr TLUD"
> Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
>
>
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