Re: LETS ADOPT A UNIVERSAL POT

["Dean Still" <dstill@epud.net>]

Dear Lanny,

Glad to hear that you want to continue the Rocket Wok project. I'll try from
my end to use the stove as much as possible, get the students to use it and
give it a real try out. And I'll get you all the feedback. Also inform the
List.

I looked at your improved pot skirt and my two cents worth would be that
using a insulated Rocket combustion chamber under the pot gives us a lot of
draft so I wouldn't think that diminished draft would be a problem. Mark
Bryden who advises me about stoves, has the idea that increasing the force
with which hot flue gases contact the pot helps to punch through a still air
boundry layer so I wonder about the value of increasing dwell time, slowing
hot gases, as a big determinant of heat transfer. I don't know and the
perfect test might be to compare results from a straight skirt and your
spiral. I do know that the right sized gap has a tremendous effect on heat
transfer and that this gap is very small. Larry uses as a rule of thumb
keeping the same cross sectional area all through the stove so bigger pots
use smaller gaps.

Of course, the pot shape is a huge factor. A pot that touches more water
inside is better, therefore a large diameter pot with a little water in it
boils quickly. In our tests, big pots generally score higher than small
pots.

Could I then take this opportunity to forward a suggestion which Ron and I
tossed about on a train heading from Rugby to London? Let's form one center
of sanity in the bigger stove world here on the CREST list and all agree on
a pot size/amount of water that we all use in our tests! Then we can compare
results of tests. Until we do so, this factor will confound comparisons.

At Aprovecho we now use a nine inch in diameter steel pot that is five
inches high. We use five pounds of water in it. But I'm perfectly happy to
switch to liters!!

If we establish the UNIVERSAL POT SIZE FOR TESTING/AMOUNT OF WATER we will
have done something that the befuddled stove world has not accomplished in
decades! Let's do it and maybe we'll force the rest of the stove world to
follow...

Best,

Dean



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