[Stoves] Jatropha and its future

Wed Aug 10 15:14:47 CDT 2011

Ron

Thank you for your questions about the Jiko Safi, the jatropha seed stove
that Jet City StoveWorks is currently testing.  I apologize for the delay in
response, but I had to pass the questions on to our developers as I am not
technically competent to answer all of them.

Why use jatropha in the Jiko Safi? Why whole seed? 

Frankly, we got involved in developing a jatropha seed stove because it
hadn’t been successfully done.  Past efforts resulted in a very fast, smoky
burn.   Jonathan Otto, who has been working in East Africa with farmers
engaged in jatropha production, knew about the past failures and jatropha’s
abundance there and urged us to try.   One of our developers, Dave Covert,
is an emeritus research professor in Atmospheric Sciences from the
University of Washington and the other, David Otto, is a contractor/
tinkerer extraordinaire in Seattle.  They had not traditionally been
“stovers,” but they are now.

As you know, jatropha is a very common tropical and sub-tropical non-food
plant with high energy content, available from Haiti to Bhutan to Indonesia.
It can be easily cultivated as a hedge row and on land not suitable for
other crops. In many areas of the world we have reached 'Peak Wood." Things
will not change for the better as population expands. One estimate suggests
less than 4% of the jatropha seed is harvested.   We believe this largely
unused rural energy source has potential as an alternative to tree burning
stoves, both charcoal and wood.  We believe that “there is no food security
without fuel security” and jatropha can be a secure fuel.  Our hope is to
make the alternative stove available to the people who are now walking for
hours past jatropha on their way to a diminishing supply of trees.  We
expect that eventually jatropha seed will also be available on the street
corners in villages and urban areas just as the much more expensive charcoal
and kerosene are now.

In several places around the world, there are experiments going on with
jatropha seed cake and rice hull blends where seed is purchased from the
farmer then transported to a center with the electricity necessary to run
three machines: an extractor that removes about 95% of the oil, a hammer
mill processes the seed cake with the rice hulls and other ingredients, and
a pelletizer to form the material in a way it can be burned.  Finally the
pellets are transported back to the farmer/cook. This approach to using
jatropha could prove to work well in areas that have the machinery and the
electricity. 

In the meantime, Jet City StoveWorks is focusing on a whole seed as a fuel
for its simplicity, availability and very small carbon footprint as well as
putting the farmer/ cook in charge of her fuel.  It is a natural pellet
stove.

How did this stove come to have a central air duct, a chimney, no port
adjustment equipment, the amount of secondary air holes etc.?

We started with several specific goals: 

(1)   The stove was specific to jatropha with its high energy content. Other
seeds with high oil content may work: castor, croton and sunflower seeds
come to mind, though some have competing uses.  We will be testing them in
time. 

(2)   The stove must be direct, intuitive and simple to use, requiring only
a demonstration of how to light a TLUD stove. 

(3)   The stove will operate with natural draft: without fan if possible and
without moving parts--the bane of all machines in developing areas.

(4)  The stove must be designed to have the lowest possible emissions and
remove whatever pollution that is created away from the cook and her family.

(5)   The stove must be durable and long lasting. 

(6)   The stove's truly important field test is its success in meeting the
cook's needs as she prepares daily meals because only then will it be used.

The stove evolved over the past twelve months to its current form. Starting
with TLUD principles (e.g. seeking the correct balance of primary and
secondary air,  thank you Paul Anderson), we then made rough calculations of
the energy captured in the seed and started building and modifying in a
typical iterative process. Typical stove designs all had too much primary
air and often a promising design would work well in some respect but not
all.  For example, we had one model that would boil water like crazy but the
temperature just above the fuel was over 1100 C.  When the central air duct
was added in a week long testing at the wonderful facility at CREEC in
Uganda, the opposing secondary air currents brought the turbulent flame down
to a flat, reliable pattern.  We are experimenting with an adjustment that
allows the primary air to be shut off at the end of a burn to cut off the
smoke that usually occurs at that point.  We are currently doing pollution
testing, advocate open source principles and so will be posting information
at our new web site which is currently under construction.
http//jetcitystoveworks.com  

The Jiko Safi is currently being manufactured by metal workers in Arusha,
Tanzania, who we have assisted in the financing of the tools and jigs
necessary to produce the stove within the tolerances required.  That is the
model we expect to use wherever we introduce the stove so there will be
local economic development opportunities as well as someone available to
repair the stove, if necessary.  It is currently designed to be used only
outside.  We hope that kitchen testing will tell us whether it can be used
indoors as long as the chimney is ventilated to the outside.

The testing and manufacture is under being done with the assistance of the
Department of Agriculture, Partnership for Development, JANI, (Jatropha
Agriculture and Nutrition Initiative in Tanzania, and Pamoja, Inc. 

Thanks for your interest and questions.  We welcome suggestions.

Jan 

  _____  

From: rongretlarson at comcast.net [mailto:rongretlarson at comcast.net] 
Sent: Monday, August 08, 2011 8:21 PM
To: Discussion of biomass cooking stoves; Jan Bianchi
Subject: Re: [Stoves] Jatropha and its future

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:  <mailto:janbianchi at comcast.net> janbianchi at comcast.net
Date: Mon, 8 Aug 2011 08:08:37 -0700
To:  <mailto:stoves at lists.bioenergylists.org>
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 < <mailto:mpare at gatech.edu>
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_JatrophaSe
edCookingStoveDevelopmentPromotion.pdf>
<http://www.vrac.iastate.edu/ethos/proceedings2011/OttoOttoCovert_JatrophaSe
edCookingStoveDevelopmentPromotion.pdf>
http://www.vrac.iastate.edu/ethos/proceedings2011/OttoOttoCovert_JatrophaSee
dCookingStoveDevelopmentPromotion.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>
<http://smallredtile.tumblr.com/post/3246717546/marc-in-the-wild-there-were-
many-arguments-about>
http://smallredtile.tumblr.com/post/3246717546/marc-in-the-wild-there-were-m
any-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>  <http://notwandering.com>
http://notwandering.com

On Mon, Aug 8, 2011 at 1:36 AM, Crispin Pemberton-Pigott <
<mailto:crispinpigott at gmail.com>  <mailto:crispinpigott at gmail.com>
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>
<http://pubs.acs.org/doi/full/10.1021/es201943v>
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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