[Stoves] Testing Cookstoves: Autocorrelation and White Swans

[Julien Winter]

Hi Paul;

I think you raise a good point.  A stove may be designed specifically for
pellets.


If the designer of the stove may say, "mine is for pellets only," then
that is what it is tested for.

When testing stoves, I think that the test results should specify a
recommended range of power levels, or fuel types that could be used.  In
fact, a really good laboratory testing for a stove would produce
performance curves with power output (on the x-axis) and cooking efficiency
and emissions (on the y-axes).  That way we could find out if a stove has a
"sweet-spot" of optimal operation.

If a designer hopes that their stove will work on a range of fuels, then I
think the test procedure should challenge the stove over that range.  The
general conclusion could be something like, "this is a clean, general
purpose stove, tier-4 stove, but please don't try to flash-fry a goat."

In my experimental ND-TLUD, high gasification rates (50 g/m²s), which I
call "flash-fired goat," causes temperatures in excess of 1,100 °C in the
TLUD reaction chamber.  That is not a good thing for a long-lived stove.

What designers of stoves may try to do is look at where the stove performs
best, and try to add design features that make it difficult to operate the
stove outside of that range.   That could be in the size and dimensions of
the fuel chamber,  the size of the fuel loading port, limiting the maximum
amount of primary air, or by designing a burner that limits gas flow
through the stove (an example of which I will post shortly).

In the end, how the stove is used is up to the user.  If they want to use
it outside of its recommended specifications, then there isn't much the
stove designer can do about it.


Cheers,
Julien.


-- 
Julien Winter
Cobourg, ON, CANADA
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