[Stoves] Re: Stoves Digest, Vol 23, Issue 9

Wed Jun 7 04:50:40 CDT 2006

  Comment:

  wood energy (Firewood & Chacoal) is a nutural choice  to many poor poeple in the third world paticularly here in Africa.Improved wood stoves, in the strickest sence of the word is debatable. to realy find the difinitionof "improved' is difficult. becouse firewood is not a clean energy as compiled to grid electricity, biogas etc 

  For those involved in charity oriented project this  (Improved stove)sounds sexy  to the poeple they are working with.Yes they is some deffrence compiled to tratiditional stoves.
  what i'm trying to say is firewood and chacoal is a poor man source of enegry period. And its up to Goverments in Africa to improve their poeples lives.This will reduce a numbers of con arts poporting to be  helping the poor acess biomass energy efficient stoves and wining wards on their exspence.

  Chewe

  Many programmes that have been introduced  in many african countries are more to with
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Today's Topics:

1. RE: improving charcoal stoves (Crispin Pemberton-Pigott)
2. Re: Central channel combustion stoves. Was RE: Henson
CenterFiure Burner System (Crispin at newdawn.sz)
3. Phosphate bonding of clay and other speculations
(Crispin Pemberton-Pigott)
4. RE: Phosphate bonding of clay and other speculations (Dean Still)

----------------------------------------------------------------------

Message: 1
Date: Tue, 6 Jun 2006 12:57:27 +0200
From: "Crispin Pemberton-Pigott" 
Subject: [Stoves] RE: improving charcoal stoves
To: "Stoves" 
Message-ID: <0cea01c6896b$c75b6740$69413f45 at Averatec>
Content-Type: text/plain; charset="iso-8859-1"

Dear Friends

Jason asked:
>All else being equal* how does the CO output of 'good' charcoal
>stoves compare to the sorts of fuels typical of a rocket stove?

The problem is to find an 'improved charcoal stove' that meets the 
definition of 'improved'.

A JIKO is not really an improvement over much these days. It has "Brand X' 
and the new ones should be compared with it. I guess the problem is to find 
really bad metal charcoal stoves against which to compare your 'new 
improved' stove.

For example, if you are measuring CO only, a JIKO is not an improvement over 
a metal grate.

If you are measuring specific fuel consumption, a JIKO is better. In fact 
it is pretty good as long as you don't look at CO.

If you are measuring affordability, a ceramic stove will 'win' over a JIKO 
because it is cheaper and has about the same performance. If it is an 
'improved' ceramic stove it will be cheaper and have much lower CO.

If you are measuring lifetime of the investment, the metal stoves stand up 
pretty well, with the best ones being stoves which you can change the parts 
that break or wear out - as is the case with a JIKO.

So...taking the present state of the art in the kitchen, the CO output of 
the most common 'improved Kenyan JIKO' is really high compared with just 
about any wood stove, and the specific fuel consumption is 'medium'. All of 
them can be improved with skirts and for the most part, more space between 
the fuel and the pot so the flames are not quenched.

Regards
Crispin 

------------------------------

Message: 2
Date: Tue, 6 Jun 2006 17:16:09 +0200
From: "Crispin at newdawn.sz" 
Subject: Re: [Stoves] Central channel combustion stoves. Was RE:
Henson CenterFiure Burner System
To: "Kevin Chisholm" , "Paul S. Anderson"

Cc: alexis belonio - Philippines , Stoves

Message-ID: <0d1001c6897c$4d001980$69413f45 at Averatec>
Content-Type: text/plain; charset="iso-8859-1"

Dear Friends

Kevin wrote:

>Not to be argumentative, but what Lanny has configured in a raw form is
>really a Side-Lit Updraft Gasifier, a S-LUD Gasifier Stove.

I have a problem with this description because it is not a gasifier any more 
than a JIKO isa gasifier. As I have said before, all coal fires are gas 
fires. All charcoal fires are gas fires.

A charcoal fire is not going to burn from the inside to the outside like a 
sawdust stove does. Nor will it burn from the top down like Reed's stove.

It will be burn like John Davies' packed bed coal stove, which is more 
technically a gasifier than Lanny's burner is.

The interesting thing about Lanny's fire is that it has a hot metal ignitor 
maintained at a high temperature by convection and radiation to light gases 
and sometimes come from the right and sometimes the left.

I have not gone into detail about the downdraft coal stove I have made for 
JHB but while investigating it I found that it the 'grate' is made from 
sheet metal punched with lots of holes, it smokes. When the grate is made 
from thin wires, they stay hot enough and ignite what passes through them. 
Lanny has built a center-fire system that uses the wire grate of the 
downdraft stove rolled into a tube.

It is OK, it is as far as I know his idea first, but making a hole in the 
middle is not new at all, packed, unpacked, whatever.

It might turn out to be a surprisingly effective way to get the CO down, 
though I suspect it is not at the moment because of a lack of air through 
the center. That still have to be investigated.

Best regards
Crispin

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------------------------------

Message: 3
Date: Tue, 6 Jun 2006 16:32:21 +0200
From: "Crispin Pemberton-Pigott" 
Subject: [Stoves] Phosphate bonding of clay and other speculations
To: "Stoves" 
Cc: Bruce Berger 
Message-ID: <0d1201c6897c$548e9be0$69413f45 at Averatec>
Content-Type: text/plain; charset="iso-8859-1"

Dear Friends

One of the great things about an internet discussion group is that you can say things that are wa-a-a-y wrong and no one will fire you for it. Now how about this idea:

I have been looking at how ceramic stoves are assembled at the microscopic level and all things considered, I don't think many of the stoves we see are very 'ceramic' at all. There are strong phosphate bonds - strong chemical bonds which are pretty heat resistant. I am suggesting that several 'traditional' approaches to making clay products are (mostly) phosphate bonded.

Consider this: people add cow dung to clay to improve the 'performance'. It is usually assumed with some degree of support that the reason the clay lasts longer in a stove is that the holes produced by the fibres make it into a more flexible and insulative. Suppose the real reason was that the phosphates in the dung are creating a stronger product that is not really held together by melted clay minerals (ceramic bonds) but by chemical ones.

And this: people add a variety of things to clay to make it 'better' and the secret ingredient may in fact be phosphate, added accidentally, creating a stronger product.

And this: making 'clay bricks' from ant hill soil (which is full of dried, fresh grass and biomass, works (makes a decent brick) when the product is fired at temperatures far too low to be ceramic-bonded. I suggest it is the phosphates in the biomass creating a chemical, not ceramic bond.

So....how about we try making 'ceramic' stove parts deliberately salted with phosphates? The insulative bricks used in the 6-brick Rocket Stoves could be made just as easily, but they would be a lot stronger (resist their inherent nature to disintegrate from thermal shock) if phosphates were added.

What natural processes form them? What are the readily available sources of phosphates? 

Grass
Fertilizer (I was thinking of artificial fertilizer which is widely available?
Dung
The raw materials for detergents
Phosphoric acid (sounds dangerous)
What about laundry soap? Omo? Tide?
Bat guano
Chicken 'litter'
Rabbit manure

Instead of using ground charcoal, which has no phosphates at all, how about using hammer-milled fresh dried grass? Powdered hay. Make the porus structure using something that releases phosphates as it burns.

If there is a lot of phosphate in chicken manure, it could be mixed into the brick or ring material and when burned, would provide both little air pockets as well as phosphate bonding.

I suspect that a careful look at the chemistry of traditional ceramics would repeatedly pitch up natural sources of phosphates that are making chemical bonds in low temperature clay products like terracotta. The traditional 'bisquit firing' might just by a slight phosphate bonding, not a very low temperature ceramic bond.

What's really going on?

Ponderingly yours
Crispin

------------------------------

Message: 4
Date: Tue, 6 Jun 2006 09:04:19 -0700
From: "Dean Still" 
Subject: RE: [Stoves] Phosphate bonding of clay and other speculations
To: "'Crispin Pemberton-Pigott'" , "'Stoves'"

Message-ID: <20060606160421.67F6115 at telchar.epud.net>
Content-Type: text/plain; charset="us-ascii"

Dear Crispin,

I think that you might be right...we could run an experiment here, if you
want to design it?

Add phosphate to a brick compare it to a brick without?

All Best,

Dean

-----Original Message-----
From: stoves-bounces at listserv.repp.org
[mailto:stoves-bounces at listserv.repp.org] On Behalf Of Crispin
Pemberton-Pigott
Sent: Tuesday, June 06, 2006 6:32 AM
To: Stoves
Cc: Bruce Berger
Subject: [Stoves] Phosphate bonding of clay and other speculations

Dear Friends

One of the great things about an internet discussion group is that you can
say things that are wa-a-a-y wrong and no one will fire you for it. Now how
about this idea:

I have been looking at how ceramic stoves are assembled at the microscopic
level and all things considered, I don't think many of the stoves we see are
very 'ceramic' at all. There are strong phosphate bonds - strong chemical
bonds which are pretty heat resistant. I am suggesting that several
'traditional' approaches to making clay products are (mostly) phosphate
bonded.

Consider this: people add cow dung to clay to improve the 'performance'.
It is usually assumed with some degree of support that the reason the clay
lasts longer in a stove is that the holes produced by the fibres make it
into a more flexible and insulative. Suppose the real reason was that the
phosphates in the dung are creating a stronger product that is not really
held together by melted clay minerals (ceramic bonds) but by chemical ones.

And this: people add a variety of things to clay to make it 'better' and the
secret ingredient may in fact be phosphate, added accidentally, creating a
stronger product.

And this: making 'clay bricks' from ant hill soil (which is full of dried,
fresh grass and biomass, works (makes a decent brick) when the product is
fired at temperatures far too low to be ceramic-bonded. I suggest it is the
phosphates in the biomass creating a chemical, not ceramic bond.

So....how about we try making 'ceramic' stove parts deliberately salted with
phosphates? The insulative bricks used in the 6-brick Rocket Stoves could
be made just as easily, but they would be a lot stronger (resist their
inherent nature to disintegrate from thermal shock) if phosphates were
added.

What natural processes form them? What are the readily available sources of
phosphates? 

Grass
Fertilizer (I was thinking of artificial fertilizer which is widely
available?
Dung
The raw materials for detergents
Phosphoric acid (sounds dangerous)
What about laundry soap? Omo? Tide?
Bat guano
Chicken 'litter'
Rabbit manure

Instead of using ground charcoal, which has no phosphates at all, how about
using hammer-milled fresh dried grass? Powdered hay. Make the porus
structure using something that releases phosphates as it burns.

If there is a lot of phosphate in chicken manure, it could be mixed into the
brick or ring material and when burned, would provide both little air
pockets as well as phosphate bonding.

I suspect that a careful look at the chemistry of traditional ceramics would
repeatedly pitch up natural sources of phosphates that are making chemical
bonds in low temperature clay products like terracotta. The traditional
'bisquit firing' might just by a slight phosphate bonding, not a very low
temperature ceramic bond.

What's really going on?

Ponderingly yours
Crispin
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------------------------------

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End of Stoves Digest, Vol 23, Issue 9
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