[Stoves] Conceptioal Errors and possible pitfals.

[Paul Anderson]

Dear all,

Further thoughts about just one of Crispin's examples below:
>
> >3.  How about giving us *_ONE_* paragraph in 4.2.2  to look at  - and 
> with especially new language on how you would change that paragraph?  
> Even if that has to be a year or two from now.
>
Crispin wrote:
>
> How is this:
>
> I give you 5 litres of water in a pot and ask you to bring it to a boil.
>
> You put it in a fire and bring it to what we agree is 'a boil' by 
> which time 100 cc has evaporated.
>
> I ask you how many litres of water you have just boiled.
>
> What is your answer?
>
> That is an example of a conceptual difference. The WBT says you boiled 
> 4.9. An engineering will say you boiled 5.0.
>
> Is this cognitive dissonance or conceptual error?
>
And take this to the simmer stage, which typically is for 45 minutes in 
the WBT.   If the pot has not lid (and it does not have a lid in the 
official testing), additional water will be boiled away. Assume two 
cases, one with a very low fire and one with very high fire (a common 
result of not having much of a turn-down ratio on powerful stoves).

In the low fire case, assume that there are still 4.5 liters in the pot.
In the high fire case, assume that there are only 3 liters in the pot.

In the final minutes, the difference in the amount of water in the two 
pots is 1.5 liters, which is 33% of 4.5 liters and 50% of 3 liters.   
So, are you actually "simmering" 5 or 4.5 or 3 liters? And how much 
actual ENERGY is needed to accomplish that task if the amounts of water 
are so different?

And which stove has the "advantage" (that is, looks the best in the 
reported results) depending on what number(s) are used in the 
analyses?    (Will someone please do the math using the formulae, just 
changing the number of liters from 5 to 4.5 to 3 so that we can see the 
impact.)   This is hypothetical, but educational.

I think that this is the type of stuff that Erin was mentioning about 
issues not well understood.  If you have the answer WITHOUT doing the 6 
calculations, then you are quite special.   But I will still ask you to 
give me the numbers.

            Topic                 Stove type       Results  5 
L            4.5 L           3 L Comments:
                                     (L or H heat)

Results of
A.   Efficiency???       for LOW heat stove: ________           
______      _______          _______..........

B.           dito                   HIGH          ________           
______      _______ _______..........


C.  Result ???            for LOW heat stove: ________           
______      _______          _______..........

D.           dito                   HIGH        ________           
______      _______ _______..........

And more???

Sorry, I do not know the answers, and I am not qualified to do the 
calculations.  But I would like to know the results.   Maybe more than 
one "result" is correct and should be reported in the results of the 
stove testing?  If this is meaningless, I want to know why.

Note:   If the results of the above are NOT of interest to you, then 
perhaps none of the discussion about testing protocols is of interest to 
you.   All of us will be grateful for these types of questions being 
resolved.

Paul


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