Thanks once again AJH,
I'd really like to not have a fan - I'm not always connected to the grid
and during winter my battery bank can often get quite low.
I'm looking for something that will take a range of fuel - I mainly use
split logs / sawn branches although at times have easy access to pallets
and wood chip. Occasionally I only have access to wood that has not
been properly dried.
More response / comments in the text below......
On 09/01/2011 14:40, [email protected] wrote:
Water is traditional because it has a high specific heat but it only
(generally) stores at below 100C, Iron has a much lower specific heat but
the density is better, higher temperature is available and it doesn't
leak.
Water suits me best as I'm pushing the weight limit for the vehicle and
it will be handy to be able to dump the weight if needed (and easily be
able to add more). I'm also going to use the hot water for washing etc.
The Resolute Acclaim.
http://www.hearth.com/econtent/index.php/wiki/Downdraft_Stove_Operation
/
In the Kunzel and Kob designs this throat area is protected by a water
jacket, when we made a hot air version this area soon burned away in
steel.
Is that a problem with the GTZ stoves Crispin spoke of? (I guess that
may be a question for Crispin?). Is 'throat burn' likely to be a
problem with any reasonably efficient stove?
As I said the hopper needs to be cool and the stratified DD aims to
do this with cool primary air. If the logs are dry then little heat is
needed to get to pyrolysis temperature, at which point pyrolysis is just
about self sustaining, so evolution of offgas happens suddenly. Of course
if the logs are wet ( and the Kob happily burns 50%mc logs if a char bed
is available, from a previous run, to start it). Then the endothermy of
drying the logs prevents runaway but all the moisture has to be heated to
throat temperature and discarded as steam.
So cold primary air and/or (or both?) wet wood can act to help prevent
runaway but at the cost of combustion efficiency... I'm guessing that
runaway can be a very bad thing... In a steel stove what are we talking?
any examples?
Best
Darren
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