Dear Ron
I will give it a quick shot:
1. Is the lab pretty much going to be reserved for coal-burning stoves?
Anything people burn we will test: coal, wood, wood briquettes, oil, rubber,
coked fuels, anthracite, semi-coked coal briquettes, raw coal briquettes with
many of them being in the semi-coked categories.
2. I gather that particulate emission is particularly bad with coal in UB -
or is it just as bad from most wood burning stoves in other parts of the world?
The local inversion conditions in winter are particularly disadvantageous.
Wood, though forming a small portion of the total energy generated, is a
significant polluter on a per kg basis. It is used to ignite coal.
3. Re this sentence: "The total range of the particulate concentration from
a bad stove during ignition to a good stove during flaming pyrolysis is
10,000:1."
a. Do you feel this is true of wood burning stoves as well?
It is true of wood burned under a pile of coal early in the ignition phase. The
lower the volatile content of the fuel, the more wood needed to light it (so
far, anyway). Wood gives off extremely dense smoke at time and is very clean
burning at others. In general it never burns as hot as coal on its own so it
might put out PM emissions that are always higher than a hot, clean coal fire.
b. Would this statistic apply to recharging a relatively hot stove with
glowing embers?
Refuelling emissions are significantly lower than ignition, in the main because
the heat of the cold fuel to ignition is accomplished by retained heat.
c. Is your statement about 98% relief related to a conversion to BLDD
(Bottom Lit Down Draft)
I have seen three completely different stove types that are at least 98% lower
in CO emissions during ignition. At this time the PM roughly correlate with PM.
We are on the verge of being able to say this definitively. The three are the
crossdraft stove described here recently, the bottom-lit downdraft and the
end-lit cross-draft.
d. In your down draft stove development, are you always bottom lit?
Yes.
e. Do you think your DD work has application to wood burning stoves?
I am confident that it will burn small pellets well though it may require a
conventional pellet feeder to make a practical device that can burn for hours
unattended (which is a goal, of course).
f. Does "flaming pyrolysis" imply testing of both DD and UD (with
appropriate BL and TL modifiers?)
Yes. To date, much against expectation, I can achieve greater emission
reductions by changing the lighting and operating procedure than has been
achieved by any ‘improved stove’ that made it to market in the past 10 years.
Extensive work by the WB and ADB and others shows that actual saving of fuel
between a traditional and improved stove (which everyone has related to
emissions with little evidence at all) is about 10%. Adopting the Basenjengo
Magogo lighting technique adapted to the stove clearly reduces emissions
dramatically and increases thermal efficiency. I will put a figure on that
within a couple of weeks.
4. Can the new test lab accommodate chimneys of several story height?
We might be able to use one as short as 1.5 metres, but normally 3 metres
minimum – the lab has been constructed with an elevated platform for the stove
in order to deal with the relatively high ceiling and still get the pipe
outside. We can accommodate 6 metres easily. After that we will have to
construct something. It is important to mention that during the test the whole
stove and chimney is on a scale with a 2g resolution. We have software from
Jeremy P-P which can read a shaking scale (which I will share here).
5. The standard (?) heating stove in many nordic and slavic countries has a
single ignition each day with the chimney having a long tortuous path to the
roof - in order to capture and store the energy. Would that work in UB?
The problem with that is that the efficiency would rise to the point that the
exit temperature would be well below the point at which H2S would condense and
eat the pipes. At this time getting the heat has not been an issue. The thermal
efficiency of a traditional stove is about 65%. This can be raised to 80%.
Above that the draft reduces dangerously unless the power level is perhaps in
the 12 kW range.
6. Is there a role for more energy efficiency (bigger wall/ceiling R-values)
and solar space heating (both active and passive)?
Randy at U of Waterloo has modelled the building with a general case
spreadsheet and it includes the solar input. Maybe, the answer to your
question. We can model the influence. I hope so. Insulating the gers (yurts) is
very effective however it also raises the CO because the stoves are leaky. Well
sealed, people may be badly affected. We have to change the stoves and reduce
their heat output which is quite hard to do below 5 kW. Reducing the size of a
semi-coke briquette fire is quite difficult. Only 600 or 700 g per hour would
be needed. There is no practical stove in that category. The fuels are
speculative at best and the housing improvement people are not really talking
to the stove people about what the heat demand is. There are no stoves suited
to a really well insulated small house.
7. You cite 400,000 ignitions per day. What is the total number of stoves in
UB? What is the relationship between space-heating and cooking? Same stove?
Started sometimes for cooking only?
Heating and cooking is done on the same stove. When it is not all that cold,
people light the stove 3 or 4 times a day. In mid-winter it is running most of
the time and the air is much cleaner. This winter it was 12 C below normal and
the coming one looks like it will be as bad or worse. Because of this, most
people kept their stoves going and the air was unusually clear in Jan-Fed.
8. There is mention of different fuels. What are being considered?
Above.
Gotta run
Regards
Crispin
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