[Stoves] Test methods for cook stoves

[Philip Lloyd]

Dear Frank

 

You say "There are two we are interested in when picking out a stove. (a)
biomass / task and (b) time / task"

 

I beg to differ.  We have little choice of biomass or task - both are almost
entirely determined by the user. Then the important variable is NOT the time
for a task, but the emissions during the (pre-determined) tasks. Granted,
the shorter the time the lower the emissions are likely to be, but that
doesn't necessarily follow.

 

Our target is cleaner cookstoves, fully accepted by users.  I cannot follow
your logic in suggesting that our choice of biomass/fuel and our choice of
task can be at all relevant to achieving that target.

 

Kind regards

 

Prof Philip Lloyd

Energy Institute

Cape Peninsula University of Technology

PO Box 652, Cape Town 8000

Tel:021 460 4216

Fax:021 460 3828

Cell: 083 441 5247

 

 

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Frank Shields
Sent: 17 March 2015 06:52
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Test methods for cook stoves

 

 

Greetings Stovers,

My suggestions:

 

Test methods for comparing Stoves.

 

1)   The units of interest: There are two we are interested in when picking
out a stove. (a) biomass / task and (b) time / task

2)   Variable = the Stove. We swap out different stoves, run the test and
compare the results for biomass per task and time per task.

3)   Controls; there are two: (a) fuel at one end and (b) task at the other.

 

Control (a) Fuel

We walk up to the stockpile of fuel in town that has been gathered and piled
and pull out what we want.  If we want to test a Rocket Stove using 2.5cm X
2.5cm X 10 cm long kiln dried sticks we pull out the bigger pieces and have
them sawed and dried.  The rest of the pile we carry back to the forest and
scatter around under the trees.  Paul for his TLUD needs uniform pieces to
keep an even flame front so he takes out what he wants, chips them to size,
and screens out the fines.  The fines and overs are carried back to the
forest and scattered.  Richard collects the material he can turn to mush and
sends the rest back.  Stoves using pellets and sticks are done the same.
Use whatever you want as long as it comes from the pile.

 

Control (b) Task

The task chosen must have a clear end point.  The start is easy - it's when
the match is struck. 

 

Everything else is NOT part of the test.  Our goal is to reduce by
elimination variables and get control over the ones left so the test can be
conducted at any lab and all will come out with the same results. 

 

We don't care about the chemistry of the gases, smoke, 2.5 pm, stability of
the stove, toxic chemicals, hot surfaces that can burn, or anything else.
If Stove A works better than Stove B then check the gases, make some
adjustments and have Stove B re-tested. If, for example, Stove A completes a
task using less biomass and in a shorter time than Stove B but stove A
produces a lot of smoke - then Stove A wins.

 

Everything else are 'Conditions' that must be meet.  There are lots of them:
paint streaked with runs on new stoves produced is a condition unacceptable,
poor welds, toxic galvanized metals, poor quality metal - all conditions
unacceptable.  Smoke, toxic gases, hot surfaces or unstable are all
conditions unacceptable.  Too heavy to move or won't take my favorite pot
are more conditions.  But these have nothing to do with the Test. We need to
keep the Test real simple.  All the Conditions in the list must pass or
don't bother doing The Test OR make corrections before testing. 

 

 

Also;

Control (a) Fuel; we are interested in mass of the biomass used but we can
normalize it to energy for convenience and when comparing 'like fuels' when
the on-site fuels are not available.  When measuring energy I fully agree
with the method Dean used at Stove Camp. The problem is there are so many
unknowns and guesses of the energy content of the different parts of the
fuel.  Perhaps its possible to get good precision (replicates) but I can't
see how the accuracy (real value) could even be close. Therefore, without
knowing of a better replacement, I believe the E450v energy value for the
fuel is the best one to use because it is easier to determine.  I realize
E450v has its own limitations.

 

Regards

 

Frank

(retired)   

 

Frank Shields
franke at cruzio.com

 

 

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