[Stoves] Going back to 3-Stone Fire [Was Re: Chinaandcookstoves]

Xavier Brandao xav.brandao at gmail.com
Tue Dec 26 13:40:25 CST 2017


Dear Kirk,

 

Did you receive my last email?

I just reforwarded it to you. It has the answers to your questions :

 

“KH  I too would like to test it with one of these “good” tests.  When will they be available?  I have been waiting for four years now. “

Actually this question has been asked, and answered, many times, especially recently.

The CSI and HTP are valid and reliable testing protocols, they are available here:

https://drive.google.com/drive/folders/0B5rmmRmIsdlnQlRQX3A1cXVOQ3M?usp=sharing  

 

These protocols have been available since 2012.

 

It is great that you agree to test your stove with an alternative protocol. But why only in December 2018? Would there be an opportunity to try it before?

 

“I can tell you its performance right now because its performance is measured by the sensors and filters which you have said are not part of the disagreement with the WBT.  According to the sensors and filters, it is clean burning.“

I’m not sure you understand. The WBT testing protocol is severely flawed. Its results, whatever the equipment you are using, are not reliable. You can have the best sensors and filters, you cannot trust the emissions results that come out of a WBT. You’ll have to use another testing protocol for that.

                                                                                                                                                          

Thanks a lot for sharing the end results of your tests. Is it possible for you to share the original spreadsheet, that has all the data and calculations?

 

Best regards,


Xavier

 

 

 

De : Stoves [mailto:stoves-bounces at lists.bioenergylists.org] De la part de Kirk H.
Envoyé : samedi 23 décembre 2017 09:59
À : Discussion of biomass cooking stoves
Objet : Re: [Stoves] Going back to 3-Stone Fire [Was Re: Chinaandcookstoves]

 

Crispin,

 

>If I understand you, you want to know if I object to the WBT calling for the use of ‘sensors’ – is >that correct?

 

KH  No this is not correct.  What I asked is if the disagreement with the WBT includes the sensors and filters.  The answer is no.  The question was intended not to be specific to you but rather to address the general disagreement.  

 

>All testing uses sensors. Why would someone object to using sensors? How else would >measurements be made? 

 

KH  You are projecting into my words your own thoughts.  I never said anything about any objection to using sensors.  I only wanted to know if the sensors were considered part of the WBT and so part of the disagreement with the WBT.  The answer, as you have said, is no.

 

>The WBT has a fixed testing sequence of power and control. It does not represent cooking >anywhere in particular, though it says in the documentation that it is a proxy for cooking. “Rating >stoves” using a universal test sequence of operations is nearly pointless because it cannot predict >what will happen if someone uses it to cook. If the test doesn’t represent use, how can the result >tell us something that will inform policy? You wouldn’t buy a child safety seat that was tested >that way.

 

KH  None of this was in my question or my intention.

 

>Measurements can be made using any instruments you like. Xavier tried using one instrument >and didn’t like it. He is a customer and was dissatisfied. I am not.

 

KH  Again not in my question or intention.

 

You asked if he objected to making measurements is that correct?

 

KH  Again no.  Please do not project into my words your own agenda.

 

>If so I find the question silly, to be frank.

 

KH  Yes it is a silly question.  I am glad that I did not ask it.  Again projecting your agenda, this time apparently to misdirect the reader into believing that my actual question was somehow silly.  Why would you want to discredit my question with this misdirection?

 

>The instruments required to make measurements mentioned in the WBT are not part of the >testing protocol, they are part of the test apparatus used when conduction the procedures listed >in the protocol. Test protocols should list the measurement range and precision required to get a >valid result within a confidence interval. The WBT does not contain any such description that >would produce results within the range required by the IWA. Writers of Standards include such a >list of needed equipment so as to provide the quality of result needed. This has nothing to do >with the equipment Xavier bought. It has to do with the test method and the claims which an be >made for its results. Such things are normally decided at the beginning during a conceptual >analysis of the purpose of the experiment and the quality of results needed.

 

KH  Again, projecting your agenda.  I once worked with a man to whom I would have to sometimes ask questions.  He would not answer the question but would talk all around it with a very long and intellectual sounding response.  I would have to ask him the same question three or four times before I would finally get a straight answer.  You are reminding me of him.

 

>Processing the recorded measurements uses a method included in the WBT document. The >method is defective on many counts – it contains approximately 75 systematic errors at present. >Some are major errors and can be (but might not be) misleading.

 

KH  Processing what recorded measurements?  From the sensors, filters, or the WBP (water boiling portion of the test).  I was told earlier the sensors were not included in the WBT, so it must be from the WBP.  

 

>I object to two things: the claim that a WBT can be used as a pre-screening method before field >trials are attempted. That is nonsense. A stove designed to burn a certain fuel and cook certain >meals might perform very badly on a standard WBT and very well in the field. Numerous >investigations support my POV. Claims that stoves ‘generally perform better in the field if they >perform better in the lab using a WBT’. So what? We can’t use ‘might generally perform better’ >as a rating.

 

>The second thing I object to is conceptual errors embedded in the test, and the arithmetic errors, >some of which are fundamental to the claims made for the results. Obviously the claims for the >‘specific fuel consumption’ are incorrect if it doesn’t report the fuel consumed.

 

KH  How did we get here from my question?  Again projecting your agenda.  I never asked anything to which this is a response.  

 

>I look forward to the day when you have your stove tested using a good test method that is well >grounded in science and engineering so we know what its performance actually is. It sounds >really good.

 

KH  I too would like to test it with one of these “good” tests.  When will they be available?  I have been waiting for four years now.  

 

       I can tell you its performance right now because its performance is measured by the sensors and filters which you have said are not part of the disagreement with the WBT.  According to the sensors and filters, it is clean burning.  It is also adjustable from high to low.  It is simple to use and all who have used it for cooking love it.  I hope it will take its place with the Champion, the Prime and all the other excellent stoves out there in the world.

       The WBT measures the heat from the stove entering into the water in the pot.  This of course is only good for the one combination of pot, pot holder and skirt.  The final user may not use this combination, but rather a different pot, a wok, plancha, griddle or other.  Each of these needs its own test if its efficiency needs to be known.  That which the WBT was designed to measure is very ephemeral, agreeing with what you said above.  I wonder if these “better” tests are the same?  However, the purpose of the WBT, sensors and filters (or the “better” tests), as I see it, is to help in the design of the stove such that it burns the fuel with the best possible efficiency and cleanliness, and to maximize the amount of produced heat that is available to the cooking device, whatever it may be.  This will be useful in the field.  Comparisons with other stoves is, from my point of view, important but secondary.

 

Kirk H.

 

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