[Stoves] cook stoves for Cameroon

Huck Rorick huckrorick at groundwork.org
Sun Sep 21 00:50:03 CDT 2014


Jed, Ron, Anh, Crispin, Philip, et al,

 

I want to express my deep appreciation for your comments and ideas.  It will
take me some time to absorb and respond.  I want to pass these questions to
our team in Cameroon.  They have poor internet access and may not be able to
participate very fluidly in the group discussion.  I will respond to your
questions and suggestions as soon as I am able.

 

Thank you very much.

 

I am copying here a recent correspondence from Pearly, one of our team in
Cameroon, regarding fuel.  Please understand that we are all new and
learning.

 

One question she has I will highlight.  We need detailed plans and
instructions for constructing some test stoves.  We expect to try a number
of possibilities and to learn how these fit with local conditions.  

1.	If you can guide us to any clear plans and instructions (for people
new to this) that would be a great help.  
2.	Feedback on her description of fuel types will be interesting.  
3.	Her comments raise questions of how fuel use and agricultural
productivity relates to slash and burn agriculture.  I presume that one
reason for slash and burn is that it is a relatively easy way to clear the
land.  But it seems very wasteful of the fuel.  One of the things that I
like about gasifier stoves is that the heat used to produce charcoal is not
wasted but rather is used for cooking.  If you consumed all that fuel (the
slash) for cooking and got charcoal out of it (for more fuel or biochar for
the soil) and ash for some additional nutrients, that seems very
interesting.  But you don't need that much fuel for cooking.  So is there
another use for the energy that also produces charcoal/biochar?  Using the
fuel to produce charcoal also seems wasteful to me as the heat for producing
the charcoal is wasted.  

 

Please excuse this very preliminary thought.  But it is fascinating to me to
think of all that unused fuel and how it might interact with soil fertility.

 

As a kind of side note, I am a builder as well as architect.  I use almost
all my scrap wood for fuel for heating (different climate than Cameroon).  I
would never consider throwing it out or burning to get rid of it (which some
people do).

4.	There are lots of other questions her note raises that I will leave
for later.

 

Pearly's note:

Hi Huck. 

 

I have talked to a few people and they all seem to be interested in making
cook stove. I will try to involve a welder or someone with experience in the
group. Keeping in mind they always give positive answers, we can only see
their true commitment while executing. If we are to test it here we will
need quite detailed instructions here.

I have asked about other fuels. They do have corn cobs. Some have nut shells
if they sell groundnuts but since they have no idea that they can be fuel,
nobody is keeping them. But they can be used to complement the firewood if
we tell them. I think people would be very happy with stove that takes in a
variety of fuels so that they can basically just throw things in.

 

It is important to understand the slash and burn system in the village and
its linkages with firewood. People usually leave their land to fallow for 5
years and will burn with fire to clear the land for cultivation (usually in
March). Some of them transport their firewood to use but many also just let
the wood burn. They even produce charcoal this way but throw them away if
nobody request for them. And household produce charcoal too sometimes when
burning their firewood. The perception is that firewood is abundant. Timothy
says he has lots of wood rotten in his farmland. So many might not switch to
other fuel that cost money. 


But if we start to encourage the use of other easily available materials to
complement firewood, this will in a way reduce firewood use and helping
environment sustainability. Charcoal like sawdust is a new introduction into
the village. I would say it has its potential if we let people know as they
cook faster than firewood. It will not substitute firewood but it would help
if they are used to complement firewood if our stove takes it too. 

 

Pearly 

 

 

From: Ronal W. Larson [mailto:rongretlarson at comcast.net] 
Sent: Friday, September 19, 2014 4:33 PM
To: Discussion of biomass; Joshua Guinto
Subject: Re: [Stoves] cook stoves for Cameroon

 

Huck etal

 

            I am looking forward to the next note from Jed.  He has the most
artistic units of anyone on this list - by far.  I'm not sure what he is now
working on, but I know that some recently have made char.  Jed - can you
report anything on how successful you felt things went at the Aprovecho
stove camp - for your char-making design?

 

            I mainly write though because I have not heard Jed ever talk
about "legos".  The TLUD stoves being sold by Anh in Vietnam are squarish -
and might well be very appropriate for modifying for use with
interchangeable (presumably square - and colorful) blocks.   Look up Anh's
website (http://www.greengenstove.com/index.php/vn/)   Sizes could be
different for every family - but with one modular "Lego"  building block.
Nice idea that I don't recall seeing before.  

 

            I can conceive of these as being light and hollow to also
provide good thermal insulation.   And artistic.   Maybe even filled with
vermiculite or a volcanic material.  Jed is asking about local clay - as
this design could be a good choice for the Cameroons.

 

Ron

 

 

 

On Sep 18, 2014, at 1:46 AM, Joshua Guinto <jed.building.bridges at gmail.com>
wrote:





Dear Huck

 

My name is Joshua Guinto. You may call me Jed. Im from the Philippines Im
one of the side participants in the stove list serve. 

 

I work mostly with the rocket stoves but recent lessons i learned from the
stove design community prompted me to tinker on the gasifier camp. And so
now im working on some prototypes of rocket-gasifier hybrids made of terra
cotta and that can produce char after cooking in air tight terra cotta char
box. 

 

I appreciate your comprehensive report on the local situations that covers
the cooking habits, the fuel available, the kitchen and the food
preparations. The reports help us designers to draw ideas from our idea
banks. 

 

I have a few questions 

 

1. Palm oil was mentioned in the report. How extensive is the oil palm
plantation? Where does the oil go? 

 

What remains after extraction? Are those the seed kernels? Are they dry
after pressing? Are there oil residues remaining in the shells? What is the
behavior of these waste when used for cooking? 

 

Do you observe oil residues on the soil/base of the stove after or while
cooking? 

 

How would you describe the smoke when these wastes are used? 

 

2. Is pottery a tradition in Besongabang? Do they have enough clay deposits
and the skills to make clay pots? 

 

3. The report mentioned cooking being at some point as a social activity.
And now that you are into housing design and construction. would your
architects explore this house design paradigm of common or shared kitchen? 

 

4. If so.... how would a garden around the houses clusters be affected by
the house design? Do you see a shared garden? or at a minimum a place for
social interactions? 

 

i ask these sociological questions because it connects deeply into the
stoves and kitchen and garden  and house design. 

 

As i understand it from the report, the households would prefer a a stove
with a table top, several ports and one that leads to a corridor where they
prepare food, do the laundry and eventually lead to the garden. 

 

It is a kitchen that is semi enclosed but allows interaction with the rest
of the household chores as well as their neighbors. 

 

If this understanding is correct, then you have there a community element
that is worth preserving and nurturing, even if it has to begin with the
stove design. 

 

And if this is making sense... i will present on the next round the stove
prototype which im working now. It is a lego brick stove that can be built
as a rocket stove or as a gasifier stove for a single port or several ports,
with or without a chimney or a table top...  from individual lego shaped
fire bricks. 

 

There are more to discuss on this thread but i park my ideas for now. 

 

Jed Guinto 

Philippines

 

 

 

2014-09-17 19:27 GMT-07:00 Huck Rorick <huckrorick at groundwork.org>:

Hi All,

 

I found myself a little confused by the discussion.  

 

Not being expert in the field, this is how I would pose my questions:

1.	There is a certain amount of energy per kilogram of wood (I'm going
to stick with wood for the moment rather than all biomass).
2.	When burned, some of that energy is realized and some is not, i.e.
there is not complete combustion.  How complete is the combustion?  How much
energy is released?  That would be the first measure.  I want this because
it tells me about one component of the system and is useful for design.  It
does not tell me the net result for the user.
3.	How much of the released energy goes into cooking?  That would be my
next measure.  That should tell me what weight of wood people have to
collect to cook their food.  It is worth noting that the amount of energy
that goes into cooking is also affected by the pots and lids used as well as
how they fit onto the stove.
4.	It is also important to know how much energy was expended to get the
fuel and prepare it for use.  Some of that energy is human energy so it gets
treated a bit differently and has a different impact.  For example, it
doesn't convert simply to climate impact (are humans low global warming gas
emitters?).  If you cut up the fuel a lot and process it a lot there is a
cost there.  I don't know how that stacks up for gasifiers vs other stoves.
5.	Regarding charcoal.  I am presuming you can still use the charcoal.
I was, apparently erroneously, under the impression that gasifier stoves
could continue to receive primary air and therefore burn the charcoal.  I
actually liked that idea because it was simple and used most of the energy
in the stove.  If you take the charcoal out of the stove you then have a
couple of options for using it.  You can burn it in another stove, which has
some appeal as you can do a different kind of cooking with it (e.g. BBQ, or
?).  But also seems like quite a bit of work and complication for a small
amount of charcoal.  Or, you can use it in the soil. So another question:
6.	Is a gasifier stove with charcoal (biochar) buried actually carbon
negative?
7.	Then the other important measure: what are the emissions?

 

And, a kind of crude question: with the ins and outs of this discussion is
it the case that rocket stoves or some other stove is more efficient than
the gasifiers?  In my question by efficiency I mean kg of wood required for
a Cameroonian to cook their meals?

Which stove do they have to carry more wood for and do more fuel preparation
for?  (I'm not sure how you measure the combined work for those tasks).

 

Huck

 

From: Paul Anderson [mailto:psanders at ilstu.edu] 
Sent: Monday, September 15, 2014 9:25 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] cook stoves for Cameroon

 

Huck,

Crispin wrote:

Thus 'gasifiers' are getting rated as if they do not consume fuel that is
actually consumed.

Crispin's point is that wood that is turned into charcoal is no longer wood.
THAT is true.    But there are two ways to state the efficiency:    Fuel
efficiency and Energy efficiency.    Charcoal that is created is no longer
wood.   But it is a fuel made from wood that was transformed.    And it
typically represent 25% to 35% of the energy that is in the dry weight of
the wood.  

You indicated that the area is reasonably wooded.   So it is not a case of
scarcity of wood.   

If the created charcoal is put into the soil as biochar, then that energy
content is no longer available.

You as the project leader and with your personnel can make the decision
about how to read the numbers in the reports on stove efficiency (of fuel or
of energy).

Paul



Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD  
Email:  psanders at ilstu.edu   
Skype: paultlud      Phone: +1-309-452-7072 <tel:%2B1-309-452-7072> 
Website:  www.drtlud.com <http://www.drtlud.com/> 

On 9/15/2014 10:45 PM, Crispin Pemberton-Pigott wrote:

Dear Huck

 

Just one quick point:

 

"The gasifier, as I understand it, is more efficient and has lower
emissions."

 

It depends on the test method and the metrics. It is fashionable to use the
GACC-WBT and that test does not report fuel consumption, it reports the fuel
mass equivalent of the energy consumption, treating charcoal left over as
unburned raw fuel (meaning it says the wood was not consumed).

 

Thus 'gasifiers' are getting rated as if they do not consume fuel that is
actually consumed. When you assess the performance be sure you are clear on
how the method calculates performance and what the metrics are. You may want
to measure ( and weigh) fuel needed per cooking cycle rather than use any
calculated numbers from a complex test protocol.

 

For evaluation of performance I recommend the CSI-WHT which is a water
heating test (no boiling) and a measure of the raw fuel needed per
replication of the cooing cycle. It is used by the WB in the Clean Stove
Initiative in Indonesia. Documentation (some anyway) is available.

 

Regards

Crispin in Tamil Naidu

 





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