[Stoves] [ethos] Re: Laboratory Comparison of the Global-Warming Potential of Six Categories of Biomass Cooking Stoves

[Tom Miles]

Dean,

Let's work through these issues one at a time and determine why significant
differences occur. 

Fuel. Fuel moisture and density their impact on emissions has been tested
with heating stoves. Typically a humidification chamber is used to condition
the fuel to the desired moisture. These are standard techniques used in wood
technology that I have suggested in the past. The object is always to use
the material closest to its moisture and density in actual use, as in a CCT
or KPT. This testing needs to be done and should be done at multiple
laboratories.

Test conditions. When Aprovecho tested the Mayon Turbo stove in 2005 the
results were substantially different than in 2007, especially in fuel
consumption and CO emissions. http://www.bioenergylists.org/en/apromayon05
What are the main reasons for these differences in performance? Which report
do we believe? It appears that a different pot size (2.5 L) was used in 2007
which would present the stove with a different heating load. In the past
Nordica provided some statistical analysis of performance tests which was
very helpful. Are there similar difference between the 2007 tests of the
other stoves and previous tests of the same stoves?

Tom   
   

  


-----Original Message-----
From: stoves-bounces at listserv.repp.org
[mailto:stoves-bounces at listserv.repp.org] On Behalf Of Mr. Dean Still
Sent: Tuesday, October 09, 2007 10:05 PM
To: crispin at newdawn.sz; Discussion of biomass cooking stoves
Cc: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] [ethos] Re: Laboratory Comparison of the
Global-Warming Potential of Six Categories of Biomass Cooking Stoves

Dear Crispin,

As I pointed out to Tom, we just sponsored a very long series of tests
measuring the effect of moisture content on emissions and fuel use,
specifically responding to questions raised at ETHOS. It should be
available soon. Did anyone else investigate the effects?

The wood that we use for testing is left overs from a large carpentry
shop. It is the wood they use every day. It is not especially dried for
our tests.

It seems that you imagine that drier wood favors the rocket type
combustion. However, as you can see in the report the fan stove and Karve
gasifier did well using the same wood.

Perhaps you did not see that Rob Bailis addressed some of your points with
the WBT?

As you may remember, when we were testing the Vesto I repeatedly asked you
to come to the lab to run the tests. We try to carefully learn how to run
stoves before testing them. Having the inventor run the stove gives it the
best chance to succeed as Paul Anderson knows from testing frequently at
Aprovecho with all kinds of biomass.

I think the point is for all of us to remind funders what testing is
showing. People who are familiar with scientific investigation know that
the results of experiments only show what is investigated. Does this mean
that stovers should not do experiments for fear the results will be
misunderstood? NO, it means that more and more experiments should be done
to  fill in the whole picture.

All Best,

Dean