[Stoves] Test methods for cook stoves

[Frank Shields]

Dear Philip,

see below


On Mar 16, 2015, at 11:15 PM, Philip Lloyd <plloyd at mweb.co.za> wrote:

> Dear Frank
>  
> You say “There are two we are interested in when picking out a stove. (a) biomass / task and (b) time / task”
>  
> I beg to differ.  We have little choice of biomass or task – both are almost entirely determined by the user. Then the important variable is NOT the time for a task, but the emissions during the (pre-determined) tasks. Granted, the shorter the time the lower the emissions are likely to be, but that doesn’t necessarily follow.
We have (MUST have) control over the biomass and task if we ever want to have a stove test that can be sent to any qualified lab in the World and come back with all the same results. We will continue getting nowhere, as we have for the past ten years and continue to do so, until the basics of method development is followed. That is, keep one variable and control all the others so to notice changes in the one we target. We are just piling on variables like there is no tomorrow.  



> Our target is cleaner cookstoves, fully accepted by users.  I cannot follow your logic in suggesting that our choice of biomass/fuel and our choice of task can be at all relevant to achieving that target.
>  
YOUR target is cleaner cookstoves. The person designing the legs for the stove has a target of making the stove more stable and the person inspecting the paint job has a target of making the stove look nice. 
Emissions is no more important than the paint job because neither stove will make it to market until those (and all) Conditions have been met. 



> Kind regards
>  
> Prof Philip Lloyd
> Energy Institute
> Cape Peninsula University of Technology
> PO Box 652, Cape Town 8000
> Tel:021 460 4216
> Fax:021 460 3828
> Cell: 083 441 5247
>  
>  
> From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Frank Shields
> Sent: 17 March 2015 06:52
> To: Discussion of biomass cooking stoves
> Subject: Re: [Stoves] Test methods for cook stoves
>  
>  
> Greetings Stovers,
> My suggestions:
>  
> Test methods for comparing Stoves.
>  
> 1)   The units of interest: There are two we are interested in when picking out a stove. (a) biomass / task and (b) time / task
> 
> 2)   Variable = the Stove. We swap out different stoves, run the test and compare the results for biomass per task and time per task.
> 
> 3)   Controls; there are two: (a) fuel at one end and (b) task at the other.
> 
>  
> Control (a) Fuel
> We walk up to the stockpile of fuel in town that has been gathered and piled and pull out what we want.  If we want to test a Rocket Stove using 2.5cm X 2.5cm X 10 cm long kiln dried sticks we pull out the bigger pieces and have them sawed and dried.  The rest of the pile we carry back to the forest and scatter around under the trees.  Paul for his TLUD needs uniform pieces to keep an even flame front so he takes out what he wants, chips them to size, and screens out the fines.  The fines and overs are carried back to the forest and scattered.  Richard collects the material he can turn to mush and sends the rest back.  Stoves using pellets and sticks are done the same.  Use whatever you want as long as it comes from the pile.
>  
> Control (b) Task
> The task chosen must have a clear end point.  The start is easy – it’s when the match is struck.
>  
> Everything else is NOT part of the test.  Our goal is to reduce by elimination variables and get control over the ones left so the test can be conducted at any lab and all will come out with the same results.
>  
> We don’t care about the chemistry of the gases, smoke, 2.5 pm, stability of the stove, toxic chemicals, hot surfaces that can burn, or anything else.  If Stove A works better than Stove B then check the gases, make some adjustments and have Stove B re-tested. If, for example, Stove A completes a task using less biomass and in a shorter time than Stove B but stove A produces a lot of smoke – then Stove A wins.
>  
> Everything else are ‘Conditions’ that must be meet.  There are lots of them: paint streaked with runs on new stoves produced is a condition unacceptable, poor welds, toxic galvanized metals, poor quality metal – all conditions unacceptable.  Smoke, toxic gases, hot surfaces or unstable are all conditions unacceptable.  Too heavy to move or won’t take my favorite pot are more conditions.  But these have nothing to do with the Test. We need to keep the Test real simple.  All the Conditions in the list must pass or don’t bother doing The Test OR make corrections before testing.
>  
>  
> Also;
> Control (a) Fuel; we are interested in mass of the biomass used but we can normalize it to energy for convenience and when comparing ‘like fuels’ when the on-site fuels are not available.  When measuring energy I fully agree with the method Dean used at Stove Camp. The problem is there are so many unknowns and guesses of the energy content of the different parts of the fuel.  Perhaps its possible to get good precision (replicates) but I can’t see how the accuracy (real value) could even be close. Therefore, without knowing of a better replacement, I believe the E450v energy value for the fuel is the best one to use because it is easier to determine.  I realize E450v has its own limitations.
>  
> Regards
>  
> Frank
> (retired)   
>  
> Frank Shields
> franke at cruzio.com
> 
>  
>  
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