[Stoves] Fw: Shields E450c as a way to test char-making stoves(attn: GACC testers)

Kevin kchisholm at ca.inter.net
Thu Oct 24 17:41:30 CDT 2013


Dear Paul
  ----- Original Message ----- 
  From: Paul Anderson 
  To: Discussion of biomass cooking stoves 
  Sent: Thursday, October 24, 2013 5:47 PM
  Subject: Re: [Stoves] Fw: Shields E450c as a way to test char-making stoves(attn: GACC testers)


  Kevin,

  When ALL of the fuel is consumed, then the fuel usage has a known energy usage.   No need to do additional calculations.

  # EXACTLY!! This would be the case for a "Full Combustion Stove." The testing is very much simplified because there is no residual char, or partially charred wood, with an uncertain energy content.

  # Virtually all "bone dry wood" has an energy content of 8,600 BTU/Lb, or 20 mJ/kG. It is a simple matter with a spread sheet, knowing the initial moisture content of the wood, to calculate the energy contained in the fuel supplied. It is a very different matter calculate the efficiency for a "Char Making Stove". 

  # Case A: Char is recovered from the ash, and is recycled to the fuel bin. 
  With 3 or 4 runs, to confirm that there is no build-up or drawdown of char, then the "Average Fuel Efficiency" can be readily calculated. Such a test would be more expensive than a "Full Combustion Stove" because of need for repetition of test work.

  # Case B: The Stove produces char, which is burned in another stove, or is retained for use as biochar. 
  In this case, the energy content of the char is a dead loss from the fuel. It contributes nothing to reducing fuel consumption. Such char is referred to as "Ash pit carbon loss." The same test procedure that was used for a "Full Combustion Stove" would be appropriate here. 

  # Case C: The stove produces char which is burned in another stove, or is used as biochar, but it is desired to know teh energy content of the char produced. In this case, the stove would be tested as a "Full Combustion Stove", as in Case B, but additionally, the recovered char would be tested to determine its energy content. Given that the testing to determine the energy content in the char is not necessary to determine the true Fuel Efficiency of the stove, it is neither fair nor necesary to burden stoves that are intended to be "Full Combustion Stoves" with a test that is helpful only to those with an interest in char making stoves.  

  And as Crispin and others have pointed out, efficiency is measured in energy units, not in kg of wood or liters of liquid fuels.  

  # Clearly, it is impossible to measure "fuel transferred from the stove to the pot." However, one can measure the energy transferred to the pot, and it is a simple matter to compare (energy in pot) / (energy in fuel supplied), to get a figure for "Fuel Utilization Efficiency." Efficiency is not measured in Energy Units. Efficiency is the ratio of:
   Es = (Fuel Eenrgy Used Productively) / Fuel Energy Supplied) 

  Simply report efficiencies in terms of both fuel usage and energy usage for all stoves. 

  # A "Full Combustion Stove" requires less costly testing than a "Char Producing Stove" It is not necesary, fair, or sensible to require ALL stoves to bear the costs of the extra testing for determining the fuel energy loss to the char, for a char making stove.
  What would you think about the following proposal for "stove testing rules"?
  1: Stove Manufacturers shall state whether their stove is a "full burning stove" or a "char producing stove.
  2: "Full burning stoves" shall have a "Fuel Efficiency Test."
  3: "Char producing stoves" shall have BOTH a "Fuel Efficiency Test", and an "Energy Efficiency Test."

  Does that sound practical, fair and reasonable to you?
  Kevin


  Paul  

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD  
Email:  psanders at ilstu.edu   
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.comOn 10/24/2013 12:20 PM, Kevin wrote:

    Dear Paul

    People do not buy, or collect, or prepare ENERGY for a stove... they buy, or collect, or prepare FUEL

    The input to a stove is FUEL, not ENERGY

    Lanny Henson has a very simple "Efficiency Test"... he weighs his fuel beforehand, cooks up a batch of Pinto Beans, and then reports the results as "Grams of Fuel per batch of Pinto Beans." Or as Grams of Fuel per serving of Pinto Beans.
    This is about as simple and elegant and meaningful and repeatable and foolproof a test as one could wish for.  

    EVERY stove should be measured in some manner for FUEL Utilization Efficiency. SOME stoves should also be tested for ENERGY Efficiency. It adds un-necessary cost to the Stove Testing Procedure, to require that ALL stoves be tested for BOTH FUEL and ENERGY efficiency when only SOME stoves need to be tested for ENERGY Efficiency.

    What would you think about the following proposal for "stove testing rules"?
    1: Stove Manufacturers shall state whether their stove is a "full burning stove" or a "char producing stove.
    2: "Full burning stoves" shall have a "Fuel Efficiency Test."
    3: "Char producing stoves" shall have BOTH a "Fuel Efficiency Test", and an "Energy Efficiency Test."

    Does that sound practical, fair and reasonable to you?

    Best wishes,

    Kevin
      ----- Original Message ----- 
      From: Paul Anderson 
      To: Discussion of biomass cooking stoves 
      Sent: Thursday, October 24, 2013 1:13 PM
      Subject: Re: [Stoves] Fw: Shields E450c as a way to test char-making stoves(attn: GACC testers)


      Kevin and all,

      All stoves should be rated on ENERGY consumption as well as FUEL consumption.    That is not too much to expect.   And would alert the readers of the test reports to the difference that char-production accomplishes in some stoves.

      Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD  
Email:  psanders at ilstu.edu   
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.comOn 10/24/2013 11:00 AM, Kevin wrote:


        ----- Original Message ----- 
        From: Kevin 
        To: Discussion of biomass cooking stoves 
        Sent: Thursday, October 24, 2013 12:42 AM
        Subject: Re: [Stoves] Shields E450c as a way to test char-making stoves(attn: GACC testers)


        Dear Ron

        Do you believe that wood burning stoves will be rated for fuel consumption, but that "char making stoves" will be rated for 
        fuel consumption minus the energy remaining in the char?

        Kevin
          ----- Original Message ----- 
          From: Ronal W. Larson 
          To: Crispin Pemberton-Pigott ; Discussion of biomass 
          Sent: Wednesday, October 23, 2013 2:16 PM
          Subject: Re: [Stoves] Shields E450c as a way to test char-making stoves(attn: GACC testers)


          Crispin  cc stoves


              Fine.


          Ron






          On Oct 23, 2013, at 11:10 AM, crispinpigott at gmail.com wrote:


            Dear Ron

            We'll at least this time you are not putting words in my mouth, you are just misunderstanding what I write and as far as I see, deliberately so. 
            If you have no more questions I will be happy to move on. 
            Regards Crispin 

            >>Q10>>>
                  From: Ronal W. Larson
                  Sent: Wednesday, October 23, 2013 12:47
                  To: Crispin Pemberton-Pigott; Discussion of biomass
                  Subject: Re: [Stoves] Shields E450c as a way to test char-making stoves (attn:
                  GACC testers) 


            Crispin and list


            #1.  You have added only extraneous material re naming, China, kilns.  You did not at all address the issue of treating char-making stoves fairly.


            #a.  Same response.  You did not address the topic of differentiating between char-making stoves.  Apparently you are happy that your money making stove in Indonesia will receive a report that says nothing about the char produced?


            #b1   Same response.  You have a typo "for a that stove"   that precludes a definitive answer since I don't know whether to strike "a" or "the".  I continue to believe that the present approach being used by Jim reports everything you ask for - and always has.  The only new material I know about I am delighted with - the amount of char and the energy in the char is specifically now provided.  It was always there, but hidden.  Char-making stove people couldn't be happier with this small change in reported results.


            #b2 -i   You write about the formula A/(B-C):  "...  it has been misleading people ever since it was introduced"
                   I agree.  - but for opposite reasons than you.  It undervalues the production of char.   I am willing to let it ride, since my preference is also being shown.


               - ii    You write:   " Char? Fine, if it too can be burned as fuel. If it is not usable, it is not fuel. Same as ash as far as that stove is concerned."   I  am sorry that you don't see how unfair this statement is to char-making stoves -- where people (including you) can make money on the char - whether used as fuel or put in the ground.   You are taking income away from the poorest with your stance.
               
              - iii   Your last sentences:  The WBT was changed and that was the major point of Jim's recent webinar to which you posed a number of questions and which he answered repeatedly. 
               [RWL:  And I was happy with all the answers.]


            I am again answering that same question. 
                  [RWL:  With answers different from Jim's]


            The fuel consumption considers whether or not the remaining fuel is fuel for that same stove. If it is not, it shall be considered consumed.
                  [RWL:   You are (I think) the only one saying this should be the rule.  Certainly no-one who thinks making char in a stove is better economically and environmentally - regardless of where it ends up.  Of course for climate reasons I want it to go in the ground,  but I started on this topic in the early 1990s just to save trees.  Char-making stoves can do both, but since char-makig stoves are more efficient and cleaner, char-using stoves are on their way out.

              End of short story. Take it up with Jim if you do not agree with this reality.
                 [RWL:  I see no need to.  I think Jim is handling "reality" correctly and has already said so on this list several times.] 














            On Oct 22, 2013, at 5:56 PM, "Crispin Pemberton-Pigott" <crispinpigott at gmail.com> wrote:


              Dear Ron

              >Crispin and stoves list  (again ignored - why?)
              1.      The "game"  I am playing is to ensure that charcoal-making stoves are treated fairly.  Saying that existing char at the end of a run has been "consumed" is not fair.

              How do you suggest we term the fuel that enters a stove once, each time the stove is operated through a burning cycle? Should that be the fuel consumed? The fuel needed per cycle? The fuel use? The fuel demand? Give it a name and let's see how it flies.

              We are speaking of course of raw biomass in this case. Whatever biomass goes into a stove, per cycle, drawn from the available supply, and which needs to be drawn again the next time, needs a name.

              In the strict sense of the word 'consumed' it has been consumed as far as that stove is concerned. In another sense, from an outside perspective which can see additional uses for that remainder, whether it be ashes or char, it has 'produced something'. No problem. One can view it that way, but it will not change the raw fuel demand for a new cycle unless some of it is fuel to that same stove. There is no other practical way to communicate to people the amount of fuel a stove requires to be harvested and provided each day.

              In China they have a test that runs for a month. A stove is installed and cooked upon each day for a month. The amount of fuel it consumes during that month is calculated. Then they know what the fuel consumption really is. If there is a huge pile of char left afterwards, they do not consider that an 'efficiency'. I can't say I am surprised.

              If you are in the char making business, you still have to consider how many cubic metres of trees are needed each day. That is the raw fuel consumption of the char making kiln. The char produced is not a raw fuel efficiency, it is the output efficiency of the char making process. No problem.

              We both owe a duty of care to the people buying and promoting stoves to correctly report the amount of biomass that is needed to fuel the stove per cycle or per day or per month.
              2.  Under a) - I repeat my original claim - you have no test in mind that will differentiate between char-making stoves.   If char is there, it has not been "consumed".

              Well you can read the above again if you like. If there is char remaining that is not fuel for the stove from which it came, it comes from fuel which the stove consumed. Word it as you like. I thought you would be asking for a report on the char production efficiency with a rating on the energy content per kg and the % volatiles. That would make sense if you wanted to sell it for income. I am hoping to do exactly that in an area of Indonesia where there are many candle nut shells. It makes really good charcoal fuel when burned in a TLUD which people can sell for income.

              When assessing the fuel consumption of the TLUD that makes that char, we will get the mass of fuel consumed per cycle, the energy content and rate it accordingly. Another stove that burns the same fuel and cooks the same amount and produces no char will consume a lot less raw material. All we are doing is reporting how much the stove consume per cycle.

              3.  Under b) -  The key sentences are your final two:   The direct cause is that the more char produced, the less fuel was claimed to have been consumed, which is clearly untrue. That is why the WBT was changed."       If char exists, the claim of less fuel is "clearly true",  not "clearly untrue".  

              My claim is related to the amount of raw biomass needed to be put into the stove each time it is used. Your claim is to view the char remaining as fuel. This may or may not be true for a particular stove. If that char is fuel for a that stove, then the char can be credited as unburned fuel. The point is to tell the prospective buyer what the raw fuel consumption is.

              Further,  the use of the formula A/(B-C) goes back at least to VITA days and is in there today.   On this main point under dispute, the WBT was NOT changed (thank goodness).  Or if I am wrong, please give a cite.

              Yes it does go back that far and it has been misleading people ever since it was introduced.  It was written on the basis that the desired measurement was not the raw fuel consumed each cycle, but the efficiency with which the heat was developed in the fire and transferred to the pot. That is why it was called (in those tests) the 'heat transfer efficiency'.  It isn't really the heat transfer efficiency, but it was given that name. The heat transfer efficiency is a useful number for stove designers. When making changes like pot to stove clearance the number will change. But it is not and never was the fuel consumption figure, even for the fry fuel consumption, because the consumption depends on what happens to the fuel remaining. If it is long sticks that can be burned tomorrow, fine, it is unburned fuel. Char? Fine, if it too can be burned as fuel. If it is not usable, it is not fuel. Same as ash as far as that stove is concerned.

              The WBT was changed and that was the major point of Jim's recent webinar to which you posed a number of questions and which he answered repeatedly. I am again answering that same question. The fuel consumption considers whether or not the remaining fuel is fuel for that same stove. If it is not, it shall be considered consumed.

              End of short story. Take it up with Jim if you do not agree with this reality.

              Regards
              Crispin






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