[Stoves] WBT disagrements

Sun Jan 14 16:56:05 CST 2018

Philip, 

In the US it often takes three peer reviewed papers just to start the conversation with agencies. Replication by different people seems to be the trend. This paper is a good start. 

Thanks

Tom 

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of plloyd at mweb.co.za
Sent: Sunday, January 14, 2018 1:09 AM
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] WBT disagrements

Thank you, Tom. As far as I am aware, it was not presented anywhere - just submitted for publication, refereed and published.
Thank you also for the copyright point. I shall bear it in mind in future.
Philip Lloyd

Sent from my Huawei Mobile

-------- Original Message --------
Subject: Re: [Stoves] WBT disagrements
From: Tom Miles 
To: 'Discussion of biomass cooking stoves' 
CC: 

Philip,

Thanks for the article. Where has this work been presented? WBT sponsors likely won’t answer questions unless pressed to do so with a clear demonstration of need. The most vocal critic on this list has said that he will not present his case in person. Who will?

Please do not post copyrighted material to the list. The article is available for purchase or may be requested directly from the authors. 

The article can be found at:

http://www.sciencedirect.com/science/article/pii/S136403211630692X?via%3Dihub

The full title and author affiliations are as follows:

Systematic and conceptual errors in standards and protocols for thermal

performance of biomass stoves

Zongxi Zhanga,b, Yixiang Zhanga,b,e, Yuguang Zhoua,b,⁎, Riaz Ahmada,b, Crispin Pemberton-Pigottc, Harold Annegarnd, Renjie Donga,b

a Bioenergy and Environment Science & Technology Laboratory, College of Engineering/Biomass Engineering Center, China Agricultural University, No. 17

Qinghua Donglu, Haidian District, Beijing 100083, P. R. China

b Key Laboratory of Clean Production and Utilisation of Renewable Energy, Ministry of Agriculture, China Agricultural University, No. 17 Qinghua Donglu,

Haidian District, Beijing 100083, P. R. China

c Sustainable Energy Technology and Research (SeTAR) Centre, University of Johannesburg, Republic of South Africa

d Energy Institute, Cape Peninsula University of Technology, Bellville, Republic of South Africa

e Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis,

Campus Box 1180, One Brookings Drive, St. Louis, Missouri 63130, USA  

⁎ Corresponding author at: Bioenergy and Environment Science & Technology Laboratory, College of Engineering/Biomass Engineering Center, China Agricultural University, No. 17

Qinghua Donglu, Haidian District, Beijing 100083, P. R. China.

E-mail address: zhouyg at cau.edu.cn <mailto:zhouyg at cau.edu.cn>  (Y. Zhou).

http://dx.doi.org/10.1016/j.rser.2016.10.037

Received 5 May 2015; Received in revised form 20 September 2016; Accepted 25 October 2016

Renewable and Sustainable Energy Reviews 72 (2017) 1343–1354

Available online 03 November 2016

1364-0321/ © 2016 Elsevier Ltd. All rights reserved.

Tom

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Philip Lloyd
Sent: Friday, January 12, 2018 10:16 PM
To: 'Discussion of biomass cooking stoves' <stoves at lists.bioenergylists.org <mailto:stoves at lists.bioenergylists.org> >
Subject: Re: [Stoves] WBT disagrements

If you could find time to read Zhang et al, Systematic and conceptual errors in standards and protocols for thermal performance of biomass stoves, Renewable and Sustainable Energy Reviews 72 (2017) 1343–1354 (attached) I’m sure you will begin to understand why none of the WBT critics is particularly interested in going to ETHOS to discuss WBT. The WBT sponsors need to answer those findings first.  Until then, silence seems strongly merited. 

Philip

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Tom Miles
Sent: Saturday, January 13, 2018 6:50 AM
To: 'Discussion of biomass cooking stoves' <stoves at lists.bioenergylists.org <mailto:stoves at lists.bioenergylists.org> >
Subject: Re: [Stoves] WBT disagrements

If challenging the WBT is so important why not discuss it with your peers? The purpose of ETHOS is to have a conversation about these issues. After 18 months of criticism of the WBT on this list I expected to see a presentation with a scientific comparison of stove test methods. I don’t see one on the agenda. Are none of the WBT critics going to ETHOS?  

http://www.ethoscon.com/ethos-2018-agenda/

Tom

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Kirk H.
Sent: Friday, January 12, 2018 5:57 PM
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org <mailto:stoves at lists.bioenergylists.org> >
Subject: Re: [Stoves] WBT disagrements

Anh,

Thank you for this information.  It is useful for myself, and hopefully everyone, to know how the charcoal is being used where you are in Vietnam.  The conflict on the char calculations is alive and well, but you are making good use of the char, whatever path the discussion goes.

Thank you,

Kirk H.

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From: Anh Nguyen <mailto:ntanh72 at gmail.com> 
Sent: Friday, January 12, 2018 12:50 AM
To: Discussion of biomass cooking stoves <mailto:stoves at lists.bioenergylists.org> 
Subject: Re: [Stoves] WBT disagrements

Dear All,

>From my personal point of view, charcoal should be calculated in lab test because charcoal do contain some energy value that is usable.

In practice, for charcoal making stove, users can use charcoal in 2 ways. 

1- they can stop the stove and save charcoal for next time use. 

2- they can leave the charcoal burning (most of people in Vietnam using this way). That charcoal will produce hit enough to cook, simmering food for some more time (can be equal time to the burning with flame, depending on stove design/fuel use), very useful for several type of food that need some slow cook or just keeping warm. If we do CCT, PKT test, cooks will use the charcoal this way and it will be calculated in the test result, so if we leave out the charcoal in lab tests, it would miss something and create miss leading result when compare lab test vs CCT, KPT.

Anh

On Thu, Jan 11, 2018 at 2:32 AM, Paul Anderson <psanders at ilstu.edu <mailto:psanders at ilstu.edu> > wrote:

Stovers,

I highly agree with what Crispin and Xavier are intending to do.   Their method of compaisons (the spreadsheets) needs to be very clearly explained so that others can see what are the differences and then clearly see what are the concequences.   Will this be "operational" in time to have some results to be discussed at ETHOS?

I suspect that INTERPRETATION of the results might still be different.  For example, how charcoal (a byproduct, if any) is acknowledged (or omitted) needs to be clearly stated.

At ETHOS this month I will present some quantitative (financial) results about charcoal  from some TLUD stoves in India.  The results are quite favorable and will give one perspective on the value of produced charcoal, and that can be compared with the value of the wood fuel that did not get burned to do the residential cooking.

And then there is the case of when pellet fuel is made from either agro-refuse (like corn/maize cobs)  or from non-wood energy crops (grown to be fuel), IN CONTRAST TO WOOD FUEL that impacts forests that are either sustainable or forest-depleting.   

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu <mailto:psanders at ilstu.edu> 
Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com <http://www.drtlud.com> 

On 1/10/2018 10:56 AM, tmiles at trmiles.com <mailto:tmiles at trmiles.com>  wrote:

Thanks to Crispin and Xavier for working up a spreadsheet comparing results from the three methods. Hopefully that will show the strengths and weaknesses of each of them. Repeatability within a reasonable range is clearly important. 

Tom 

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Kirk H.
Sent: Wednesday, January 10, 2018 8:46 AM
To: Discussion of biomass cooking stoves  <mailto:stoves at lists.bioenergylists.org> <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] WBT disagrements

Ron,

No, there was no discussion on this topic.

Kirk H.

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From: Ronal W. Larson <mailto:rongretlarson at comcast.net> 
Sent: Tuesday, January 9, 2018 5:19 PM
To: Discussion of biomass <mailto:stoves at lists.bioenergylists.org> 
Subject: Re: [Stoves] WBT disagrements

Kirk: cc list

              Thanks for hanging in there.

              I wonder if,  in your off-list dialogs with Crispin and Xavier, you could determine how they would go about utilizing your own work in charcoal-making stoves - in the Tier ranking system.   

              The WBT methodology coming out of the ISO-285 activities (in WG2 and many other methodologies) supports what I have termed the “denominator equation”  e3=e1/(1-e2). e3 (to be used in the Tier rankings)  can also be written as e3=e1/(e1+i) = 1/(1+i/e1).  This, since e1+ e2 + i = 1 (where i is the inefficiency).   Note no negative sign in the denominator, when written this way.

              It seems they want to treat all char as a waste material (become part of the inefficiency term i);   e2 should apparently always be zero in their thinking.  Did you learn anything on this point?

Ron

On Jan 9, 2018, at 1:12 PM, Kirk H. <gkharris316 at comcast.net <mailto:gkharris316 at comcast.net> > wrote:

Crispin,

I think your question was appropriate and the answers were hopefully helpful.

No, you don’t deserve credit for being helpful.  I asked my question and instead of answering it you projected your agenda into me and proceeded to answer your own projections, not my question.  Without an answer from you I had to make a guess.  You didn’t like my guess and became angry and in that anger actually gave me a partial answer.  You proceeded to push your agenda using me as a pawn, but not fully answering my question.  I had to fight tooth and nail with you and Xavier to get tid-bits of information.  Finally I had enough tid-bits of information to assemble a coherent answer.  The credit is mine for fighting for an answer.

Kirk H.

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From:  <mailto:crispinpigott at outlook.com> Crispin Pemberton-Pigott
Sent: Tuesday, January 9, 2018 2:13 AM
To:  <mailto:stoves at lists.bioenergylists.org> Kirk H.;  <mailto:stoves at lists.bioenergylists.org> Discussion of biomass cooking stoves
Subject: Re: [Stoves] WBT disagrements

Dear Kirk

I think your question was appropriate and the answers were hopefully helpful. There are many lab based systems of ‎measurement and sometimes only a few measurements are necessary to make great progress in improving an existing product. 

Something that can be separated ‎is this: Aprovecho is not 'the WBT'. What they do and how they do it is not dependent on using the WBT which is merely a fixed test sequence with a set of measurements and calculations. 

Philip's comment about the WBT telling you whether or not the stove is improved is most pertinent. If the test didn't tell you how it performed the first time, getting a different wrong answer later may, or may not, be helpful. This is the crux of the problem. 

Tuning a stove requires making refined measurements, not generalizations. A series of small, say, 3% improvements can result in a 12-15% improvement in fuel consumption or power change time, or turn down ratio. If the test cannot reliably tell you the change ‎for better or worse is 1% vs 4%, the results are guiding you by chance. 

A very carefully done experiment must, not should, deliver reproducible results‎. Prof Lloyd has I think been the most specific on this point, much more than most commenters. As an experimentalist not familiar with small stoves, he was expecting that stove performance tests would deliver the same sort of replicability as other physics experiments. The WBT doesn't do that because of the conceptual errors embedded in what it measures, when, and how it calculates the outputs. 

On the face of it, why should the calculations make a result variable? Dean once posted here that if there is a mistake that is applied to every test, then it is not important. 

The difficulty is that the mistakes manifest errors unequally in different stove types, additional to the variability created by conceptual errors. Prof Lloyd was forced to abandon the WBT in favour of a method without those errors in order to continue his work.  

Thank you for participating offlist in the discussions. ‎Xavier are I are discussing the preparation of a spreadsheet with a number of tabs, one each for different versions of the WBT and CCT. Putting in the lab info from a test will create copies of the test on each tab with the different calculations so the outputs can be compared. I think we will be able to find 12 versions of the calculations, maybe 15.

We can also prepare one tab without the errors. This will be the formulas to be applied that are developed from first principles as per the HTP/CSI where the requested metric is calculated from only the necessary measurements made to achieve it. 

Given the limitation of the test sequence itself,, high, high, low power, it would give 'an answer' that could be used to compare the performance of two slightly different versions of a stove, or different fuels, pots, ambient temperature and so on. 

In South Africa, any kerosene stove tested in Johannesburg or similar altitude must also have an emissions test conducted at a coastal location. Similarly in reverse. The performance on such a pair of tests must be highly reproducible. 

Such a comparison sheet can be very helpful for convincing the casual user that only the corrected version should be relied upon. Failing that, we must retire, as there are always going to be those who will not make the effort to understand the technicalities of the field in which they choose to dabble. 

After that comes the issue of contextuality. If the WBT with 'standard wood'‎ is used to develop a stove that will be used to simmer soup burning dung, there is no hope. It would be like perfecting a gasoline engine for 89 octane fuel then operating it with diesel oil. 

All stoves are used in some context so the assessment will be most relevant, even for internal metrics for sub-systems, if the test conditions are relevant to the expected pattern of use. The WBT is advertised as a 'cooking simulation'. That's OK. Pick and report. 

Regards 

Crispin 

All,

I recently asked a question about whether the disagreement with the WBT included the sensors, filters and computer graphing as well as the water boiling portion of the overall test.  I have received several responses from Crispin and Xavier (some off list).  From all that was said by them I have assembled an answer:  The sensors, filters and computer read-outs are part of the WBT, but not part of the disagreement with the WBT.  So this disagreement is with a portion of the WBT test, not all of it.  Also, I believe that Crispin has a second disagreement that questions whether some sensors and setups are able to provide accurate read-outs.  I believe that this is a legitimate concern for scientific study, however I also believe in different standards for different purposes.  Perfection is not always needed.

This is an acceptable answer for me.  It is not pro or con to the WBT or any protocol.  My question was intentionally neutral.  I just wanted to know the extent of the disagreement.  

My position on the WBT remains neutral.  I use it because it is available for me in a lab, whereas the other protocols are not.  The WBT does very well for what I need.  It tells me if a change in the stove is helpful or not.  Whether or not it is perfect science is not important for my interests.  

I believe that Aprovecho (ARC) plays an important part for wood stove development and education and I remain a supporter.  

Kirk H.

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