[Stoves] Stoves Digest, Vol 2, Issue 23

[Crispin Pemberton-Pigott]

Dear Andrew

Do you refer to cooking stoves? I was actually referring to the air quality
problem in UB.

I agree there are different perspectives on stove problems.

In Africa for a long time it was a fuel saving problem and stoves were
developed to have a higher heat transfer efficiency.

Later emissions were a larger issue with indoor air quality being the main
point. Fuel saving is not as important save from the (incorrect) point of
view that if one reduces fuel consumption exposure to emissions is
automatically reduced.

The situation in Ulaanbaatar is one of outdoor air quality. In fact indoor
air quality is pretty good compared with outdoors. As the place is so cold
that one has to heat the home to live more than a few days, everyone needs
to generate heat somehow. The best answer is thermal insulation and this is
definitely being addressed, however upgrading the entire housing stock is a
formidable challenge. GTZ is working on demonstrating super-insulated
retro-fitting to old Soviet era precast concrete buildings (basically 6"
slabs of concrete as walls). Millennium Challenge Corp is demonstrating
super insulated ger blankets (yurt covers). They cut heat demand in half.

The problem is there are no stoves that match the lower heat demand of the
highly insulated buildings. The emissions from the stoves are produced in
the first 40 minutes of burning - almost all of it. If the home is insulated
well, it means less heat is required and people light the stove more often,
which increases total emissions. That was not the plan, eh?

So the lighting emissions have to be modelled into the stove use equation.
If we want to clean up the air, we have to either limit the number of
ignitions, modify the ignition sequence to reduce emissions, keep the home
fires burning all the time at a low level (not good with existing hardware)
or increase the amount of fuel burned so the fire is running at a normal
power level and not being re-started several times a day.

The increasing popularity if mass walls for storing heat is likely to
increase emissions even though at least in theory they save fuel (because
they are condensing heat exchangers).

Interesting problem. We need a 2 kW stove for heating an super insulated
ger. There is no such  thing at the moment as a clean burning 2 kW coal
stove. I am thinking of trying a fan stove.

Regards
Crispin


-----Original Message-----

On Saturday 30 October 2010 09:00:32 Crispin Pemberton-Pigott wrote:

>
> The present mantra is, "This is not a thermal efficiency problem, it 
> is an emissions problem!"

I think this list has had the consensual view that it's an emissions and
heat exchange problem since Ronal first introduced Kirk Smith's views about
15 years ago.

AJH