[Stoves] old patent-paper about a saw-dust stoves

[Crispin Pemberton-Pigott]

Dear Martin

 

Thanks for the references (there seems to be a lot more but editing the name
didn't find it).

 

>Cover-sheet with the description for the intention of the insert
("Einsatz") 

http://www.collection-appareils.fr/brevet/Kaftanski/DE423728/page1.pdf

 

>Drawings with description:

http://www.collection-appareils.fr/brevet/Kaftanski/DE423728/page2.pdf

 

I want to saw that 'back in those days' people did not have very good
measuring equipment and as a result stoves were not very clean burning, even
when people thought they were.

 

I have not yet seen a single stove over 30 years old that has good
combustion throughout its cycle. I realise that is limited to what I have
seen and is defined by my interpretation of the word 'good'. However, the
most interesting thing is how close they were to have good systems for
burning all sorts of fuels, and how we are finally able to tune them to be
profoundly cleaner - often with small changes to air and containment.

 

There is all sorts of weird and whacky and useful stove inventions and they
are certainly an inspiration for the array of developers popping up all over
the world. But I recommend not getting too excited about them as they are
until some testing has been done to show what the emissions are in real use.

 

Having done an awful lot of testing myself it is clear that for nearly every
stove there are magic moments when the conditions are just right and
everything works perfectly, or nearly perfectly. Even a box full of coal
will at some point have amazingly low CO and later, nearly no PM at all. In
a big application (like a power station) those conditions are maintained
continuously if possible. 

 

The impression given is that some device may be clean when things are going
well. That is an achievement in itself. Modern equipment now shows that we
need to take care, in particular, of the ignition emissions and quite often,
the refuelling emissions. With some of the char producers, the tail end
emissions can be an issue as well. 

 

One of the people attending the DoE meeting in Washington (Omar from Mexico)
mentioned the use of a 'burn cycle test'. This is basically when one
analyses what people do in the field and reproduce the same burning cycle in
the lab. Then develop the stove to lower the emissions when performing that
cycle. We use exactly that approach in Ulaanbaatar so we will know what the
in-field efficiency, fuel consumption  and emissions will be.

 

When examining these old stoves we could determine how they were supposed to
be applied to cooking or heating problems and work out what the burn cycle
was that they were addressing. Then test them to see how good they were.
Stove usually refer to reduction in smoke and thermal efficiency. Then by
applying what we now know about combustion, we could tune these devices to
work well/better on the burn cycles of interest. Boiling water in one cycle,
making tortillas is another. Heating a room, yet another.

 

We may find in the haystack of ideas a glorious 'needle' that perfectly fits
what we are after, even if we have to polish it up a bit.

 

Sawdust stoves would be so useful in many places because sawdust has been
declared a hazardous material at many waste dumps (because it catches fire
and burns underground). 

 

Has anyone seen sawdust burning stoves that seems to work reasonably well,
or are they all plagued by rising thermal power, for example? I am hoping
that some form of TLUD will work with really small sawdust particles because
there is so much of it around.

 

Thanks

Crispin 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20110116/67f49550/attachment.html>