From Charlie Sellers:
I chased down this protocol in case it would help me with my effort to see how to compare the performance of 2 stoves differentiated by only minor design changes (not predict how they will work in the field - though we keep hoping that lab testing results can be eventually correlated with field performance, once we have figured out how behavioral, educational, and cultural issues can be overcome):
It might be considered a little obscure on the web - since if you search on the title ("Stove Manufacturers Emissions & Performance Test Protocol" - EPTP for short) you won't get much else besides this helpful presentation at NREL last fall:
A supporting journal article cited is "Influence of testing parameters on biomass stove performance and development of an improved testing protocol", written by L'Orange et al at Colorado State University and published in the March 2012 issue of Energy for Sustainable Development: http://www.sciencedirect.com/science/article/pii/S097308261100086X
and it is worth a read. For those of you who are not yet familiar with it, Google Scholar is an excellent tool for ferreting out the, hopefully, highest quality technical information - and it has no superfluous information or ads, yet. I am not sure that I am allowed to attach a copy of it here - but the authors should be able to. Note that an older, but similarly oriented, journal article from India "Effects of selected parameters on performance and emission of biomass cookstoves" - was published in 2002 by Bhattacharya et all (Thailand), in the journal Biomass and Bioenergy (http://www.sciencedirect.com/science/article/pii/S0961953402000624).
The EPTP seems for the moment to address some of my personal needs related to "quality control" - The The EPTP seems for the moment to provide for some of my personal needs related to "quality control", one of the things that it was developed for - hopefully reducing test-to-test, tester-to-tester, and lab-to-lab performance variations using ways that I am familiar with from the product development and manufacturing world (like the general Gauge R&R method http://en.wikipedia.org/wiki/ANOVA_gauge_R%26R). Introducing a lid (they use a piece of foam floating on the surface, plus some other tweaks) addresses the point that few of us are in this to study the time dependent kinetics of water evaporation during the sometimes lengthy approach to boiling, and how to calculate the impact of a continuous decrease in water volume using a simple spreadsheet. Again, it is not a substitute for a properly conducted KPT for estimating field performance, and I look forward to the discussion of where/when it is appropriate for users on this list.
So... since our last discussion on this was about whether to use pot lids or not, and after you weighed in so heavily, I report that I have switched to a lidded method (and will try your heterogeneous approach as well). I owe those interested details on my own testing (presently still statistically inadequate - doing enough tests is very time consuming), comparing the WBT and variations on the EPTP for the structurally similar Envirofit and Ecozoom commercial stoves. One thing that I am seeing is that the two tests do not seem to produce results which are quite as similar (for me) as has been suggested, and of course I need additional testing using various fuels, etc. I am quite impressed with the ease of use and performance of both of these, and consider them a real step in the right direction for places where large volumes of imported stoves are appropriate. As I described last, one of my other interests is comparing the impacts of the thermal insulation material type on various stove performance measures in a lab-like setting, and that work is yielding some interesting results with implications for sometimes using local choices instead of unnecessarily importing that bulky component too. More as it develops.