[Stoves] Stove testing procedures

[Tami Bond]

Hi all,

Very sorry to take so long to follow up on this. I can say something 
about what Aprovecho equipment is and also what we use in the field. 
This is only relating to exhaust gas testing-- not fuel testing.

* Measuring what? *
Through a few discussions at ETHOS meetings, we came to the conclusion 
that we need to test for carbon monoxide (CO) and particulate matter 
(PM). We also measure CO2 in exhaust gas which enables us to get 
'emission factors', pollutant per kg of fuel burned. My ETHOS 
presentations 2002-2004 are probably on the Stoves page, but also 
located at...
http://cee.uiuc.edu/research/bondresearch/stoves.html

We could test for many other pollutants (see especially the 2002 
presentation) but we hoped to settle on the CO and PM to see if we could 
do that well.

* Measuring how? Aprovecho *
Around 2003, Aprovecho-- along with a few specifications from me and 
others-- started implementing their testing lab. Dale Andreatta set up 
the flow hood which captures all the exhaust. Some of the exhaust gas is 
extracted with a little pump (bigger than fish tank, you can get them at 
Grainger in the U.S.), diluted and measured. CO and CO2 are measured two 
ways: in the *undiluted* gas with an Enerac combustion analyzer, and in 
the *diluted* gas with the CCCD-- I'm embarrassed to say I can't 
remember what it stands for-- it's a 4" PVC lump that we informally have 
named the 'bomb' and contains two small CO (electrochemical) and CO2 
(infrared) analyzers. Chris Roden, grad student here, designed and built 
the CCCD for our first trip to Honduras.

PM is measured only in the diluted gas by light scattering 
(nephelometer). Light scattering is not a perfect measurement, but it is 
one of the only real time measurements and it is better than extinction. 
PM *must* be measured in diluted gas, because some of it will condense 
gas as cools-- thus if you measure hot gas you are missing some PM.

* Measuring how? in the field *
We also measure emissions from stoves in the field-- because we 
suspected they would be different than stoves in the lab (they are). If 
you take the diluted part of Aprovecho's measurements (CO, CO2 and PM) 
and strap that on a luggage cart, you have Chris Roden's ARACHNE-- 
Ambulatory Real-time Analyzer for Climate and Health-related Noxious 
Emissions. (I admit that the acronym was made first and then we found 
the words!) We also add real-time particle absorption to that. We can 
tell if the particles emitted are black (soot) or not black. Sometimes 
they are yellow. The color turns out to be very important for climate. 
And finally we collect the particles on filters for total mass and 
chemical analysis. They are mostly carbon, what you might think of as 
'soot' or 'tar'. In order to get a diluted gas sample, we sample high in 
the plume.

We measured in Honduras in summers of 2004, 2005, 2006. The first paper 
about ARACHNE, traditional cookstoves only, 2004 measurements, will 
finally be published in a scientific journal soon (Nov 1). In 2005 we 
went back to measure improved cookstoves. These stoves had not been 
installed for very long, so the 2006 trip was to see whether emission 
performance had degraded, and also to test the contribution of fuel type 
to emissions. Results are not final yet but will come soon.


There is also a document on my web site... 'Emission testing for real 
people'... that talks about some testing issues and possible instruments 
to use. Any comments are welcome.

Sorry if I have missed some of this discussion. I have been traveling a 
lot lately and so have the Aprovecho folks.

Tami