[Stoves] Stove comparison coming

[Crispin Pemberton-Pigott]

Dear Stovers

We have now performance tests on 17 different stove types at the SEET
laboratory in Ulaanbaatar, over 50 tests in all. Some were iterations of the
same stove with changes in operating method and changes it hardware but not
really different stoves so those count as 1 model. 

 

The result will be coming soon and continue for those interested in
following it. The stoves fall into the following categories:

 

Traditional bottom lit updraft

Crossdraft

Top lit updraft

Bottom lit downdraft

 

They can also be divided into two general groups: those that can be
refuelled and those that are batch-loaded.

 

The refuellable ones can be further divided into two sub-groups: those that
are refuelled periodically and those that have hoppers for continuous
refuelling.

 

As time passes we are sure to see original and interesting new products that
challenge conventional classification.

 

We have shown that operator technique is not very important for high
emissions stoves and quite important for low emissions ones. For example a
badly lit TLUD easily fails the 'improved stove' selection criteria for
funding (a rebated subsidy).

 

The provisional minimum performance criteria are relative to a local stove
baseline. It is an emissions per net MegaJoule of heat delivered into the
home. That means it factors the actual emissions per kg of fuel by the
thermal efficiency so the actual emissions required to heat and cook are
used to make the judgement. 

 

The baseline is 650 mg PM2.5/Net MJ and CO is 13.5 g/Net MJ delivered.

Qualifying stoves will emit less than 70 mg PM2.5/NMJ and 7 g CO/NMJ.

There is also a cooking test and they have to be able to run continuously
24/7 plus a few other assessments like a 5 year life expectancy. 

 

So far at least 5 stoves are in the 99% reduction category. They are not
similar, including TLUD, BLDD and Cross Draft models. The thermal efficiency
as a space heater is usually in the 80-85% range. Cost ranges from $60 to
$250.

 

One of the more unusual models that popped up last week is a TLUD that can
be run continuously at full power 24/7.

 

A large number of interesting figures comes out of the test analysis which
includes emissions during portions of the test like the ignition and dying
fire phase. It quickly becomes obvious to the observer that start-up
emissions account for nearly all the PM emitted by a decent coal stove and
many of them are net-negative for PM during significant portions of the
brown coal burn, i.e. they are cleaning the ambient air of particulates!
Most interesting.

 

Regards

Crispin in Seoul

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