[Stoves] comparative water boiling test

[Jean-François Rozis]

Dear Crispin, 

I read by chance the comment you made concerning the comparative water boiling test, happy at the begining to have some exchange on it and after disapointed to see some misunderstanding and confusion..

So I will try to answer step by step:
- goal of this test, only for field laboratory stove, just to improve one stove or compare two stoves in correlation with specific local cooking habits. No interest for me for having international test for that, objective is to reduce sources of errors (different pots, fuel specificity, local environment, complicated "modus operandi"..), same place , same starting time, same pot, same fuel, same qty of fuel, as simple to conduct as possible.
Which one will perform better, that means with same quantity of fuel will make more useful job (heating and water evaporating)

- so I hope you agree with the interest for field developer of this test??

- If yes, ok  it's just a problem of formula.

- no need to add in calculation energy for maintaining stove pot heat, loss energy and not useful for me, and when you make the difference between stove with same pot, this amount is thus eliminated so forget it (I saw kirk Smith also has taken it out for the international WBT)

- influence of cook, not evaluated in this test, only of course in field test. Iif we have to maitain one test, for sure we will use only field test (please a simple and comparative one of course), but to see if I put higher pot rest, lower combustion chamber,.. what will happen, hopefully I have not to build one hundred stoves and to disseminate these ones in the field to see if I am right or not, for that I need a laboratory test telling me I'm in the good way or not..The final prototype will be of course validated in the field and only at that time I could tell I success..

- so the CWBT I presented is an indication valuable for Cambodia but to be adapted for local cooking habits of course..In cambodia, saving time, having for same fuel qty more power to the pot is the good way, So I simplify the calcualtion in that way, evaporating water is in that case useful energy proving I can cook faster so obtaining approval from end user..

- in other case, if you are sure to have certain power to not overpass (long and lower simmering by instance), so  you can adjust the simmering level (fix the power, by adjusting the quantity in fine of water evaporated, same in the two stoves to be compared), so don't go to DGIS to obtain formula just compare the total time to use the fixed amount of fuel. The ratio will give you idea of potential fuel saving, the longest lasting the better is in that case..I have to precise I compare stove with same way of giving heat to the pot, not one where pot is totally sunk in the stove, other only heating bottom part.

it's not the scenario to reproduce in each country it's the approach to compare stove to be reproduced, 

so following this philosophy I'm sure we can write a final description of this CWBT you can use in your context...

to be continued




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Jean-François Rozis
Tél: 0467643816