[Stoves] Irrelevant lab testing - for what purpose?

Thu Jun 1 15:43:38 CDT 2017

"'Five of the stoves presented here were also tested at the US EPA, with results agreeing within 20% or better on all fuel and emissions measures,...'"

Hang on, how does this validate the results for the 50 tests?

If they both used the same stoves and protocol, the result is as defective as the protocol. WBT3.0, which was not peer reviewed just as the Aprovecho-modified ‎v3.1 wasn't, doesn't give a meaningful fuel consumption value (because of the char energy deduction error. For emissions, that is a crap-shoot because the uncertainty of the Aprovecho-made PM test equipment is at least 50%.

As Fabio Riva meticulously pointed out (in his peer reviewed journal article), the combination of the WBT and a PEMS hood was not able to definitely place more than 75% of 'improved stoves' above 0% improvement even at a confidence interval of 0%. And that is before trying to assign some absolute value for the performance, just 'is it better at all?'

What does "within 20%" mean if the uncertainty is 50%?

WBT3.0 doesn't even correctly report the mass of water boiled and the conceptually erroneous fuel consumption formula is what was 'corrected' in v3.1 so how can it rate performance?

Unless the EPA used the same defective calculations, there is no way they could get a comparable result. If I gave the same stoves to the Brookhaven National Lab and asked them to report the performance, they could provide an answer that could serve as a baseline against which the quality of the Aprovecho testing could be ‎evaluated.

Crispin

+++++++++

To continue in my criticism of WBT and energy efficiency as a performance metric....

I discovered a paper by Aprovecho folks - Nordica MacCarty, Dean Still and Damon Ogle, "Fuel use and emissions performance of fifty cooking stoves in the laboratory and related benchmarks of performance<http://www.sciencedirect.com/science/article/pii/S0973082610000311> Energy for Sustainable Development, Volume 14, Issue 3, September 2010, Pages 161–171. http://dx.doi.org/10.1016/j.esd.2010.06.002.

.. The authors claim in the Abstract:

Performance of 50 different stove designs was investigated using the 2003 University of California-Berkeley (UCB) revised Water Boiling Test (WBT) Version 3.0 to compare the fuel use, carbon monoxide (CO) and particulate matter (PM) emissions produced. While these laboratory tests do not necessarily predict field performance for actual cooking, the elimination of variables such as fuel, tending, and moisture content, helps to isolate and compare the technical properties of stove design.

It stretches credulity that stove designs are tested on the basis of excluding fuel, tending, and moisture content.

This is engineering madness. Standard fuel, standard pots, standard water.  No cook, just the theologians of thermodynamics.  I am surprised Tom Miles thinks I am crazy to call that the dominant paradigm of stovers needs to be shaken from the root to the skies. What there is to protect will stay, but WBT not only must go, all past results of WBT must be dumped as "technical error".

It has been a technical terror.

I can understand Aprovecho engineers' vested interests in a certain kind of "stoves ideology" but I wonder if they realize just how laughable they are to the world with statements like

"From this data, it was possible to recommend benchmarks of improved cookstove performance. " and that

'Five of the stoves presented here were also tested at the US EPA, with results agreeing within 20% or better on all fuel and emissions measures, suggesting standard evaluation at various locations is possible.

Probably doesn't matter. So long as EPA and Approvecho results coincide, their interests and ideological agenda will also coincide. All in the name of fact-free, cook-free science of cookstoves.

Boil blood, not water. This whole storm of "standards" is a nightmare or a pleasant dream, take your pick. Emission rates and efficiency ratios have little to do with usefulness of a cookstove.

Nikhil

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Nikhil Desai
(India +91) 909 995 2080<tel:+91%2090999%2052080>
Skype: nikhildesai888

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