[Stoves] Internal Secondary Air
Crispin Pemberton-Pigott
crispinpigott at gmail.com
Thu Aug 11 01:27:23 CDT 2011
Dear Ron
The Mayon Turbo Stove involves a nominal manufacturing licence so you won’t find drawings available. There are now two similar looking (outwardly) versions which are quite different inside. I have not heard yet about the latter case (developed somewhere in Canada) going into production but it has greatly enhanced performance and can burn a variety of fuels very cleanly. It can still be improved, I think.
Cecil Cook got hold of an older version this week and used it to burn wood chips which are very cheap in Gambia. Wood chips let in too much air but it just cooks at a higher power. He says it is really well made.
He was also very impressed by the quality of the local aluminum pots made by the Fulani tradesmen. I am considering some cooking options to take advantage of their skills set. The pot shape is a truncated cone with flat handles at the top edge – common at that end of West Africa.
Regards
Crispin
From: stoves-bounces at lists.bioenergylists.org [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of rongretlarson at comcast.net
Sent: 10 August 2011 14:53
To: Discussion of biomass cooking stoves; Anand Karve; Priyadarshini Karve
Subject: [Stoves] Internal Secondary Air
AD (adding Priya) and list: (also changing thread list name)
1. Thanks. I remember reading/hearing of this stove but not of the internal secondary air aspect.
2. I went to http://www.samuchit.com/index.php?option=com_content <http://www.samuchit.com/index.php?option=com_content&view=article&id=1&Itemid=3> &view=article&id=1&Itemid=3
and cannot tell if there is both an internal and external supply of secondary air for the Sampada. [I can't see either type of air supply) The surprise to me was the flat, turbulent flame pattern of the Jet City design. Any photographs the Karves can share to show this unique turbulent flame?
3. There are statistics on CO and particulate emissions for this stove (per meal). Can you compare these numbers with the Sampada's (or any) competition?
4. There are some statistics on making money with the Sampada (a today's topic on this list) - that I calculate could be about a two-year payback time. If used in a commercial establishment, it would be much less. Any consumer research report on the importance of this economic benefit to the Sampada (using purchased wood in the example here - not free resource)?
5. Paul Olivier reported to me off-list that he also has tested (or will?) an (additional) internal secondary air supply. Any one else?
6. After writing above, I received Crispin's report on Roger Samson's work on a "Mayon" stove. I went to 4 sites but nothing specific showed up on internal (and both) air. Again I can't see anything about a flat turbulent flame - and am totally unsure on the geometry. Cites?
My reason for pushing this is that I think flame flatness and turbulence is important and rarely (maybe I'm wrong) seen in pyrolyzing stoves.
Ron
_____
From: "Anand Karve" <adkarve at gmail.com>
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Wednesday, August 10, 2011 10:15:53 AM
Subject: Re: [Stoves] Jatropha and its future
Dear Ron,
A stove called Sampada gasifier stove, developed by Dr. Priyadarshini
Karve of Appropriate Rural Technology Institute and currently being
marketed in India by Samuchit Enviro-Tech P. Ltd. introduced this
concept of appplying secondary air through a central hollow tube, more
than two years ago.
Yours
A.D.Karve
On Tue, Aug 9, 2011 at 11:21 AM, <rongretlarson at comcast.net> wrote:
> Jan and list
>
> This is to better understand your nice Jet City stove .(for non West Coast
> USA readers - that means Seattle - which has a lot of Biochar activity)
>
> 1. How did you happen to center on Jatropha? Have you experimented both
> with whole seeds and the residue after pressing and how does stove operation
> differ? Have you tried anything like wood chips?
>
> 2. I think the flame pattern in your stove is wonderful. As you say,
> very compact and obviously very turbulent - which must be desirable. I am
> pretty sure the idea of central secondary air has been mentioned n the past
> on this list as a possibility - but I don't recall ever seeing it in
> practice. Can you describe a bit how you came to the present dimensions ?
>
> 3. I worry that you may now have too much secondary air - as the flame
> seems to only be holding near the bottom row or two. Have you any way of
> knowing what the dilution factor is? Tried operation with a smaller number
> of interior holes (just plugging some progressively)?
>
> 4. The central "column" (maybe with a different height) looks like it
> might be able to hold a pot of the right size - since you would then
> already have the "convection shield" that gives considerable efficiency
> improvement. And you could retain the chimney height needed to get your
> desired air flow and power level. Ever been tried?
>
> 5. I have felt that controlling primary air supply to be an important
> feature of pyrolysis stoves (TLUDs). It seems your bottom set of holes
> could receive a rotating or sliding (or up and down) plate to accomplish
> that. Has that ever been tried? (This being accomplished nicely with a
> blower in the "Paul Olivier design also being discussed today.)
>
> Best of luck with what you are doing. Nice work.
>
> Ron
>
>
>
> ________________________________
> From: "Jan Bianchi" <janbianchi at comcast.net>
> To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
> Sent: Monday, August 8, 2011 9:56:48 AM
> Subject: Re: [Stoves] Jatropha and its future
>
> Roger
> That stove in the ETHOS pictures was a prototype version. The stove is now
> made from steel.
> Jan
>
> Sent from my iPhone
> On Aug 8, 2011, at 8:51 AM, Fireside Hearth
> <firesidehearthvashon at hotmail.com> wrote:
>
> Good morning....
>
> I am curious about a couple of the pictures of the stove by Otto....do I see
> galvanized sheet metal used in area's of high heat? the text talks about
> 800deg C. (1472 f.) if there is galvanized materials in contact with these
> temps it is quite possible that galvanic poisoning could kill the operator.
> A friend of mine was welding inside a galvanized pipe (large culvert for
> water drainage) when his oxygen mask failed and a green colored gas entered
> his lungs causing him some of the most horrible pain and near death
> experience imaginable. The other question I have is the material thickness.
> It does not look like this will withstand these temperatures for long. What
> is the life expectancy of this unit when exposed to these temps. Does it
> make sense to build something a bit more stout and send less of them to the
> land fill as the "burn out" too quickly with these exposures. Not all ways
> can we value things simply on "cost per unit" but "cost to the environment"
> should be taken into account. After looking at the industrial area's of
> northern China it seems to me that it is the environment which is paying for
> our "cheap" flat screens.
>
> ________________________________
> From: janbianchi at comcast.net
> Date: Mon, 8 Aug 2011 08:08:37 -0700
> To: stoves at lists.bioenergylists.org
> Subject: Re: [Stoves] Jatropha and its future
>
> Jet City StoveWorks is currently conducting kitchen tests of the jatropha
> seed stove Marc refers to in Tanzania.
> Jatropha grows wild throughout the tropics as well as recently as
> biodiesel crop there. Alternatively, and more productively, it can be
> grown as a hedge around land holdings so it need not displace land for food
> production. That produces enough seed to fuel the family cookstove for a
> year as well as have some left over to sell into the Jatropha market. It
> costs at least four times less than a comparable burn time for wood and six
> times less than charcoal.
> We are continuing CO and PM testing and hope to have our test results online
> by next month. We had a stove at Aprovecho's stove camp couple of weeks ago
> and will have one at Paul Anderson's TLUD camp in MA in August.
> Sent from my iPhone
> On Aug 8, 2011, at 2:10 AM, Marc Pare <mpare at gatech.edu> wrote:
>
> Crispin, re exisiting Jatropha stoves:
> There was this one at ETHOS this year by J. Otto and friends:
> http://www.vrac.iastate.edu/ethos/proceedings2011/OttoOttoCovert_JatrophaSeedCookingStoveDevelopmentPromotion.pdf
> and a quick picture of it running outside in Kirkland:
> http://smallredtile.tumblr.com/post/3246717546/marc-in-the-wild-there-were-many-arguments-about
> It burns whole seeds in a natural draft TLUD. Draft is augmented by an inner
> air pipe (lots of pictures of the assembly in the ETHOS presentation)
> Marc Paré
> B.S. Mechanical Engineering
> Georgia Institute of Technology | Université de Technologie de Compiègne
>
> my cv, etc. | http://notwandering.com
>
>
> On Mon, Aug 8, 2011 at 1:36 AM, Crispin Pemberton-Pigott
> <crispinpigott at gmail.com> wrote:
>
> Dear Friends
>
> I am not sure how many stove are being worked on as Jatropha seed or oil or
> cake burners, but my understanding was the main thrust was to put to use
> some of the leftovers from biofuel production, especially that was the focus
> in Tanzania.
>
> It seems those farmers who invested in Jatropha production lost about $65
> per ha http://pubs.acs.org/doi/full/10.1021/es201943v so my question is
> whether or not there is much point in working on (perhaps) whole seed
> stoves. Perhaps if the J-oil industry suffers a quick death there will still
> be a meaningful supply of oily seed fuel that can be burned relatively
> easily with a decent performance and controllability. At least until they go
> back to sunflower which looks a lot more promising.
>
> Has anyone made a sunflower seed burning stove? The oil runs up to 49% on
> some varieties.
>
> Always looking for new ideas…
>
> Regards
>
> Crispin
>
>
>
>
>
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--
***
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)
*Please change my email address in your records to: adkarve at gmail.com *
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