[Stoves] Test methods for cook stoves

Frank Shields franke at cruzio.com
Tue Mar 17 13:54:03 CDT 2015


Dear Crispin,

see below

 <snip>

1) 
We only need biomass/task and time/task as final measurements. The energy going into the water in a WBT (for example) is no more important than determining the energy going into bacon frying or energy going into a turkey roasting. Fuel efficiency calculations are just more unnecessary variables that increase the ‘noise’ of the test and result in poor precision amongst labs. 

2)
Suppose we want to list stove testing labs around the World (thats what we want to do -right?). We have 25 that send in their money to be tested to get Qualified. We send each a like stove and like fuel for testing. We form a bell curve of the results (biomass/task and time/task). Five are outliers so leaving 20 Qualified labs. 

Example A:
Lets say we add emissions testing to the Qualifying test. Five fail the emissions test and that leaves 15 Qualified labs for stove testing.  We add stability test (bag of sand on a rope swing) and 2 fail. That leaves 13 qualified labs for stove testing.   

Example B:
Lets say we make emissions optional. Ask the labs if they want to be Certified for emissions. Of the 20 Qualified labs 15 want to be Emission Certified and the rest do not want to spend the money on equipment. Of the 15 there are 5 outliers leaving 20 Qualified and 10 to be both Qualified and Emission Certified. We can add Stability and Construction inspections and many other Conditions that must be meet based on pre-determined limits. All tested by Qualified and Certified labs. 

Until we do the above - We Go Nowhere!

Once all the Conditions have been met (clean, stable, looks nice etc.) we are only left with biomass used and time to do the task. We are reduced down to the end user’s basic concerns when they look down a list of stoves and know the stove would not be on the list unless all the Conditions have passed. All this testing means nothing (except research) until we have enough control such that all labs get the same results and the results are meaningful to the group being marketed (using their available fuel and tested using their task(s)). 

Many more years will pass and we will have gone nowhere because we can’t follow basic grade school science.  How sad.  : (

Regards

Frank

Frank Shields
franke at cruzio.com


> 
> Suppose the energy consumption, which you mention towards the end, is not the major concern of the user, but PM emissions is the biggie?
> 
> Suppose the program funder wants to know how long the pile of fuel will last, rather than how much energy is extracted from the pile? These numbers are quite different, particularly when comparing stoves that don't burn the fuel completely. 
> 
> Suppose when using a new stove the household changes their behaviour a lot and uses it more to keep food warm and provide more light? If they have more burning hours available from the same pile of fuel, they may want to use them, not save fuel as it is already there. In short, do you want to measure the performance of the family or the performance of the stove?
> These very practical questions affect the design of the test. Another aspect is fuel preparation. Should time needed to cut squares fuel be considered? What about fuel flexibility? That is a major issue with users. What about moisture flexibility? Ditto. 
> 
> If we don't ask enough questions, we can't identify a good fit between a particular group of users and the available stock of stoves. In the case of a DGIS-funded project at ProBEC, they accepted the less-than-optimal fuel reduction because the lifestyle of the people was improved by running the stove longer each day which they described as 'access to modern energy' which was the main programme goal. 
> 
> Pretty cool I think!
> 
> Regards 
> 
> Crispin 
> 
> 
> 
> 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
> 
> 
> 
> 
> _______________________________________________
> Stoves mailing list
> 
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
> 
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20150317/5dd6086b/attachment.html>


More information about the Stoves mailing list