[Stoves] News: National Geographic on promotion of gas stoves over improved woodstoves - in Guatemala
Crispin Pemberton-Pigott
crispinpigott at outlook.com
Fri Sep 1 09:39:51 CDT 2017
Dear Friends
Addressing this item only, because Ron stopped reading when he would a hook he could use to avoid reading the documents needed to understand the SeTAR Centre’s HTP and the even more relevant CSI which includes the contextual testing protocol.
“[RWL5: I’ll get back to this - but I repeat that South Africa seems to support the general concept of monitoring the change in water properties in pots sitting on stoves.”
The metric that you objected to and mischaracterise, Ron, is the heat flux into the pot measured per unit area. It a measure of the ability of the stove to deliver heat into a cooking pot normalised for size. This overcome the severe limitation imposed in the WBT (and don’t pretend there is more than one WBT on the discussion table) which prescribes the use of a ‘standard pot’ without a lid.
If you would read further you could find that the important assessment by the cooks of their stove’s performance when it is working well (either high or low power, makes no difference) can be captured using this new metric that has not been used in stove testing before. It is used to assess the cooking pot (in the pot) under a condition the cook determines to be useful – for whatever purpose(s) they have.
When the stove behaviour is replicated in the lab, care is taken to ensure that the candidate stoves replicate the requirement for maximum and minimum cooking power. If they can do it, it means the stove is as controllable as the cooks in the intended market require.
The cooking can be boiling chips in oil, heating water, steaming rice – it does not matter at all. What is needed is to determine that the required performance can be achieved (or better). Water is used for this, but not boiled because boiling greatly interferes with the accurate measurement of heat gained and replication of the test sequence is made difficult.
The CSI tests using water heating (see the paper From WBT to WHT, referring to the Water Heating Test) were very successful at determining the thermal performance without boiling anything. The performance of a stir-fry wok meal can be characterised by a pot-heating rate. Any working fluid can be used for this, not only water.
If you want to determine the cooking power of a stove used for dep frying, this test can be replicated using cooking in in the pot and for the coolant in the heat exchanger, and the test sheet is set up to be able to calculate properly using any fluid, heat exchanger coil material, and can even used different working fluids in the pot and the heat exchanger circuit.
All this has been worked out several years ago. It is one of the many reasons the CSI test method is used in preference to the WBT.
Regards
Crispin
Xavier and ccs
Thanks for a courteous reply with good questions. See a start below. (Start because you gave me a lot of homework. Thanks especially for providing a great set of cites at the end (but no time yet to review any.)
On Aug 30, 2017, at 5:13 PM, Xavier Brandao <xav.brandao at gmail.com<mailto:xav.brandao at gmail.com>> wrote:
Dear Ron,
« The ISO process is open to every country - and is progressing well mostly (I listen in from time to time). »
The gates are open, but I don’t know how to pass through them. Sally Seitz and Ranyee Chiang kindly asked me if wanted to get updates from the TC 285 discussions, I said yes. Several times. I am still waiting. I asked the AFNOR in Paris, but it doesn’t seem like having France as part of the TC 285 is one of their priorities.
The ISO is a black box to me. If anyone can direct me to regular sources of information or ways I can join, I’d be most thankful.
[RWL1: Your statement that ISO is a black box answers many of the questions below. It is imperative that you learn how ISO works. Your best route would seem to be AFNOR - since you are French. I work only through ANSI - not ISO.
I presume Sally and Ranyee thought that you would start with AFNOR. Updates have been given at the last several ETOS meetings and I have written about those updates (which were very well done). We are going to miss Ranyee.
Can anyone help bring Xavier and AFNOR together? I repeat to Xavier - until you are part of the ISO process - you will be making a mistake in decrying it.
« The WBT IS valuable »
Can you explain what is valuable about the WBT?
[RWL2: My favorite on this topic is Jim Jetter. See presentations at several ETHOS meetings. I speak selfishly when I note that TLUDs shine at the WBT. I suspect some don’t like the WBT because their favorite technology doesn’t shine. By shine and value I mean that the WBT is behind most of the tier rankings - which long ago were accepted unanimously as the right way to proceed with stove improvement at this time. To me the WBT is all about improvement. If you can’t measure something, it won’t be improved. I disagree with those especially who say that there is no proven connection between measured CO and PM values in the lab and in the field. If not obtained with today’s WBT, what test is to be preferred? (answer in next question.)
« and should stay until replaced with something better »
There is already something better! Better is not right word: there is already something valid, as opposed to the invalidity of the WBT. There’s be something valid for a long time.
There are the CSI method and HTP protocol.
They are here, I sent the link to you long ago:
https://drive.google.com/drive/folders/0B5rmmRmIsdlnQlRQX3A1cXVOQ3M?usp=sharing
Tell me why you think they cannot replace the WBT?
[RWL3:
The documents I found at your above cite were from the South African SETAR. I stopped reading when I read this sentence in the last of the four there: “A cooking session using a
system with a heat flux rate of 2 W/cm 2 will boil 5 liters of water in under 25 minutes.” Sounds like a WBT to me - and the ISO process is encouraging such diversity in different countries. But ISO has accepted the challenge of an international version - not mandated to be used by everyone. Somebody please tell me I am missing something on WBTs.
The first (HTP) document similarly measures water temperature rise - albeit a little differently. I view the accuracy of the results to be so dependent on the user that whether it is one run with water loss in an uncovered pan or only concentrating on the regime where water loss is minimal and rate of temperature rise makes little difference to me. I am using the term WBT to mean that a water-containing pot is involved. I may be wrong but this HTP test seems to assume there is no production of charcoal. I predict this lack will cause a change at some point (and may be the reason we hear little favorable about TLUDs from South Africa (even though there are several capable TLUD manufacturers in South Africa. I hope they will chime in on the value of a stove test that assumes charcoal has no value.
For time reasons, I have chosen not to read the other two documents at your recommended site. Apologies in advance for that lapse and for apparently not saying something earlier about this site - which seems to strongly support the use of pots of water in stove testing (as do EVERY other test procedure I am aware of). No reason to talk of cooking rice or boiling oils- when boiling water is so universal.
Tom, this question is also addressed to you, since last time, I think you were saying there wasn’t yet an alternative.
What is so unique about the WBT that cannot be done by the CSI nor HTP?
All “the experts” I trust are advocating continued use of the WBT.
Ron, can you please list all the experts who, now, today, still advocate continued use of the WBT?
I know there is you, and there is Dean Still with whom I discussed over emails.
Can you please name these experts Ron?
[RWL4: As I have said before, I consider Jim Jetter as especially knowledgeable. John Mitchell, also of EPA, knows a huge amount about stove testing. Look at who has spoken at ETHOS meetings on these topics. Ranyee Chiang will be hugely missed at GACC. Professor Tami Bond is great - as well as some of her graduate students. Berkeley is full of competent stove people - starting with Dr. Michael Johnson. See http://berkeleyair.com/about-us/staff/ for others who really know their stove measurementstuff. I am not claiming support from Professor Kirk Smith, but his name is on at least one paper with Jetter. And both DoE and EPA funded 3-4 groups - mostly at Universities. I won’t try to mention all their names, but they are at schools such as CSU and U Washington. Again - see their presentations at ETHOS. No guarantee they support the WBT - but I look forward to hearing if any of those mentioned disown it.
On this list, I especially list Tom Miles and Andrew Heggie as likely supporters of the WBT.
Dean Still has been in this a long time and I also trust his judgement - which in part goes back to a premier early stove investigator - Dr. Sam Baldwin. I have talked to Sam quite often and have never heard any concern that the WBT was inappropriate. My concern was about making char and using the “denominator” equation - which seems to be the main dispute which I have been having for years with Crispin. And also you??
One person I am excluding from this list is myself. I have no experience with monitoring either CO or PM. I especially like measuring water evaporated because I have made a lot of progress on char-making stove improvement by using a simplified WBT. I have heard Kirk Harris say the same.
Apologies to anyone I missed or mislabeled.
You are talking about « Crispin’s » experts. I cannot help but think about the people who reviewed the CSI and HTP and highlighted the problems with the WBT.
The 2 (long) lists are below this email.
[RWL5: I’ll get back to this - but I repeat that South Africa seems to support the general concept of monitoring the change in water properties in pots sitting on stoves.
Ron, can you please critique their work? Critique the reviews or the studies? What is it that you don’t agree with?
Ron, or anyone, can you please share a list of reviews of the WBT protocol?
As you said Ron, the WBT has been used for decades. It shouldn’t be difficult then to get a list of reviews by external researchers showing how scientifically valid the WBT is.
[RWL6: I can assure you that Jim Jetter, who has written extensively on stove testing, defends the WBT. He also leads the ISO effort - which WOULD NOT be finishing if there were any doubt as to the validity of the WBT. If it is not yet clear, I am claiming you are in a small minority of “experts”.
7 months ago, the 26/01, I asked you Ron on this List several very specific questions, referring to the WBT issues.
You never responded.
[RWL7: Apologies if I didn’t respond, but I do know that I contacted many of the principal authors (and I think Riva) and think I might have reported. I am pretty sure that the basic WBT approach was not in doubt with them. What was in question was only (??) how many replications needed to be made to ALWAYS achieve what they considered a minimum level of accuracy.
I ask you these questions again, they refer to the text of the paper of Riva and al., paper that you can find here:
https://www.researchgate.net/publication/308898807_Fuzzy_interval_propagation_of_uncertainties_in_experimental_analysis_for_improved_and_traditional_three_-_Stone_fire_cookstoves :
Ron, in the WBT,
* do you contest the role of thermodynamic uncertainties (viz. variable steam production and boiling point determination) on results repeatability? Can you ensure there are no uncertainties?
RWL: I cannot so ensure - since most of my efforts along these lines was more than 20 years ago. I am sure that there are uncertainties, since many properties DO vary with altitude. But I have seen no uncertainty that applies to placing stoves at a single testing center into incorrect tiers (as measured to tenths of a tier). Boiling point determination can be different - but when you run for an hour, this is of disappearing importance, compared to who did the testing. And, if you don’t use a WBT, what do you replace it with?
* Of if there are, can you ensure they have no effect on results repeatability? How?
[RWL: I believe the existing uncertainties are acceptable - being much smaller than other known causes for measurement differences. Is there any group anywhere that has avoided all the concerns you think exist? A much bigger error for me lies with those who claim you should ignore the weight of any charcoal produced.
*
* do you have an answer to the questions about the rationale of some calculations raised by Zhang et al.?
[RWL: Give me more to go on.
*
* do you support the statistical approach recommended by this standardised laboratory-based test (the WBT) to evaluate, communicate and compare performances and emissions of tested stoves, i.e. using the arithmetic average of three replicate tests? How do you guarantee this statistical approach ensure good comparison of stove performances?
[RWL: Yes I can support the use of just three tests - if they are “relatively” close together in all tier statistics. If one test if vastly different than the other two, then additional testing should take place. The main reason for accepting three is trying to keep costs low. I gather that one can make some useful statistical importance with just two tests.
The arithmetic average is not the only data that should be given - each result should be (and is usually, I believe) given.
*
Best,
Xavier
Reviews of the HTP and CSI
The HTP was officially reviewed by an external expert group as required by the IWA 2012:11. The World Bank office in Beijing commissioned SGS Netherlands which provided a report after investigating the equipment, test protocol and calculations.
[RWL: Where do I go read that? (It is getting too late to find, read, and report back). This one looks important.
The Ulaanbaatar Clean Air Project test method for approving stove performance is the HTP before the CSI contextual portion was added, though the test conducted is in fact based on current observed practice. The Ulaanbaatar Clean Air Project test method has been reviewed and/or approved by:
* Mongolian University of Science and Technology, Prof Tseyen-Oidov and others
* Ulaanbaatar Clean Air Project, Operations Manager & Chief Engineer, Ms D Tsendsuren
* Dr B Odonkhishig and Dr Jargalsaikhan Buriad, head and Director, respectively, of the SEET Laboratory in Ulaanbaatar
* SGS Laboratories, Netherlands (who conduct most of the stove tests for EU certification), WB contract
* Team experts under Akeo Fukuyama, from the Environment Division of JICA contractor Suuri-Keikaku Co. Ltd.
* Millennium Challenge Account – Mongolia (MCA-Mongolia is the local branch of the Millennium Challenge Corporation, USA) which spend $20m on stove subsidies based on the results of the tests
* National University of Mongolia, Prof Lodoysamba, Innovation Manager, Department of Research (nuclear physicist and air quality expert)
* GTZ building energy efficiency program in Ulaanbaatar, headed by Ruth Erlbeck (reviewed by her head technical man and a young German MSc physicist Mr Henning Schulte-Huxel who wrote a lot of the chemical balance calculation block on the FUELS tab)
[RWL: Please correct me if wrong, but I don’t believe this test is at all applicable to cook stoves; it may or may not have some value for cook stoves - but I doubt seriously that this testing involves boiling water.
*
The CSI Test Protocol which includes the contextual test method appended to the HTP test method and calculations has been reviewed by:
* World Bank technical review team for Indonesia (their infrastructure engineer and technical reviewer)
* College of Engineering, China Agricultural University (CAU), Prof Renjie Dong, head of the National Key Laboratory for Biogas, reviewed it at the request of the Senior Economist heading the CSI-Indonesia Pilot
* Yixiang Zhang, PhD candidate, College of engineering, CAU. He has published several reviews of certain aspects of the test method and its calculations.
* Degan Ostogic, Lead Energy specialist (engineer) in the WB Energy and Extractives supervising the CSI-Indonesia Stove Pilot, he also required a demonstration of the method in action.
* The head of stove testing at a Western nation’s national regulatory body has reviewed the method for generating the Technical Test from a set of Cooking Tests. This provides the contextual element of the CSI Method.
* Prof Harold Annegarn, nuclear physicist, then at the Department of Geography Environmental Management and Energy Studies, University of Johannesburg
* Engineer David Beritault, formerly with GERES, for years the head of the Cambodian stove testing lab and now with CARITAS Switzerland, made a very detailed review of the concepts and calculations underlying the method. He is a co-author of ISO TC-285 WG2, 19867 Part 2.
* James Robinson, BSc (Eng), MSc (Eng), MSc (aeronautics), former head of the SeTAR Centre, University of Johannesburg.
* Dr Tafadzwa Makonese, Head of the SeTAR Centre, Research Village, University of Johannesburg
* Indonesian BNI (National Standards Body technical committee) made a conceptual review with the intention of replacing their current Draft National Standard (which at present uses an early SeTAR Centre heat transfer efficiency test protocol, the forerunner of the HTP.
[RWL: I haven’t had time to review any of these, but note again that the CSI test does involve boiling water. I don’t yet see it worth my while to review any of these. Pleas give a better cite for your top two of the above and I will try to report on its relevance to the issue of retaining the existing WBT.
The following list looks quite interesting, but too late to try to look at any, much less all. I’ll try to get at these ASAP, but would appreciate knowing of those that take specific exception anything I have said above.
Xavier - please tell me where I have let you down in the above. Anyone else find my responses insufficient?
Ron
*
Papers pointing at issues with the WBT
* Fuzzy interval propagation of uncertainties in experimental analysis for improved and traditional three–stone fire cookstoves
https://www.researchgate.net/publication/308898807_Fuzzy_interval_propagation_of_uncertainties_in_experimental_analysis_for_improved_and_traditional_three_-_Stone_fire_cookstoves
* Key differences of performance test protocols for household biomass cookstoves. Twenty-Second Domestic Use of Energy, IEEE 2014:1–11.
http://energyuse.org.za/document-archive/
To access the file, select DUE [Domestic Use of energy COnference]. Select DUE 2014. Select PROCEEDINGS. Select paper by Zhang etal (PDFs arranged alphabetically).
* Performance testing for monitoring improved biomass stove interventions: experiences of the Household Energy and Health Project. Energy Sustainable Dev 2007;11:57–70.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.461.783&rep=rep1&type=pdf
* The shortcomings of the U.S. protocol
http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1534&context=etd
* Influence of testing parameters on biomass stove performance and development of an improved testing protocol
https://envirofit.org/wp-content/uploads/2016/06/2012-influence-of-testing-parameters.pdf
* How many replicate tests are needed to test cookstove performance and emissions? — Three is not always adequate.
http://gadgillab.berkeley.edu/wp-content/uploads/2014/03/D-13-00075-Wang-et-al._final.pdf
* Systematic and conceptual errors in standards and protocols for thermal performance of biomass stoves
https://www.researchgate.net/publication/309689616_Systematic_and_conceptual_errors_in_standards_and_protocols_for_thermal_performance_of_biomass_stoves
* Quality assurance for cookstoves testing centers: calculation of expanded uncertainty for WBT
http://www.newdawnengineering.com/website/library/Stove%20Testing/Testing%20Protocols/American%20WBT,%20CCT,%20KPT/2014%20March%20WBT%204.2.x%20Uncertainty,%20Gorrity,%20M.pdf
* Key factors of thermal efficiency test protocols
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1000.3936&rep=rep1&type=pdf
* Towards a standard for clean solid-fuelled cookstoves
https://www.researchgate.net/publication/274706950_Towards_a_standard_for_clean_solid-fuelled_cookstoves
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