Re: I stake my claim of being the first to make a single pot stove to boil 1 litre of water in under 2 minutes.

["Kevin Chisholm" <kchishol@fox.nstn.ca>]

Dear Crispin

Thanks very much for your report on your test results. I pernonally would
not have thought that one could boil a litre of water in such a short time
with a wood stove.

----- Original Message -----
From: "New Dawn Engineering /ATEX" <crispin@newdawn.sz>
To: "Stoves" <stoves@crest.org>
Sent: Monday, January 07, 2002 1:25 PM
Subject: I stake my claim of being the first to make a single pot stove to
boil 1 litre of water in under 2 minutes.


> Dear Stovers
>
> I hereby throw down the gauntlet to all challengers who wish to knock me
off
> my throne as Boil King of the Stovers.
>
Well, you will be a "hard act to follow", but when I do, it will give me
great satisfaction to have beaten one of the best!! :-)

> I have this afternoon tested an unmodified Basintuthu single pot stove
> fuelled specifically for this type of a burn with ordinary pine wood taken
> from a plank in the workshop.

This is all the more remarkable, in that you are working with a practical
stove, and not just a "racing model."

 I did add three paint cans on top of the pot
> to get more updraft.

Shhhh. don't tell othres these secrets!! :-)  Actually, my design employs a
stack system also, and a small door at the top of the can, which can be
opened at about the right time, to allow the Judges to see the penny flip.

  It boiled the 1 litre in well under 2 minutes and also
> had boiled off  80cc of water when I stopped the test at 2:40.
>
OK!! This is super!! Do you think you can do a "1 minute boil???"

> The ease with which this was accomplished means that we will have to
> re-evaluate what a meaningful boiling test will be like.
>
Very good point. For one thing, it strikes me that for the "Fast Boiler
Contest", we should reduce the total fuel quantity to 250 grams of "kindling
plus fuel". You mentioned that you feel you have burned "over 200 grams" of
fuel in the test; was this estimate at the 2:30 mark, or at the 1:30 mark,
when you first heard the boiling sounds?

A simple variation of the Contest Rules would permit "The Worlds Most
Efficient Pot Boiler" contest..... using the same basic system, the Entrant
would select "just the right amount" of fuel to bring the water to a boil.
The winner would be the entrant who was able to boil 1 litre with the least
grams of "permitted" biomass fuel placed in his firebox at the start of the
test.

You don't mention the dimensions of the pot you used for your test. Would
the proposed "juice can" work on your stove system? If not, could you
advantageously make a "racing version" of it to get even quicker boiling
times?

You mention 96C as your boiling point. This is presumably as a result of
your elevation and/or low barometric pressure due to weather conditions. For
simplicity, I would propose to ignore barometric pressure in the Contest
Rules, based on the assumption that what you gain through the lower boiling
point is basically offset by the less dense air and a requirement for more
ACFM (actual cubic feet per minute) for a given heat release. DOes this make
sense to you?

Once the Draft of the Rules are put together, would you be agreeable to do a
"test run" that would confirm that the Rules were practical, or whether
there were still some holes that had to be plugged? Of course, I would
expect that you would "understate" your results, and not tell us your "real
secrets"!! :-)

Kindest regards, and many thanks for the very complete report on your very
interesting results.

Kevin Chisholm

> Sincerely,
> Crispin in Swaziland
>
> +++++++++++++++
>
> Details:
>
> Date of Test  7 January 2002, 6PM
> Mean air temperature 27 deg C
> Mass of water    1000gm
> Mass of aluminum pot    510gm (the test was done with an open pot so I
> could try to assess when it was boiling)
> Mass of water + pot    1510gm
> Mass of paper used to ignite kindling    4gm
> Mass of pine fuel put into the basket grate    246gm
> Mass of all fuel in the basket grate    250gm
> Mass of fuel added during the test    None
> Mass of water + pot at 2 minutes 40 seconds    1430gm
> Initial Water temperature 22 deg C
> Final water temperature (est from previous experiments)    96 deg C
>
> Method
> I found it very difficult to light the fire and start the stopwatch at the
> same time.  I decided to light a piece of newspaper rolled up so it
wouldn't
> go out as a match can when simultaneously holding a stove up in the air
and
> starting a stopwatch at the same time.
>
> I held up the stove in the air so I could bottom-light it with the end of
> the rolled up newspaper and when the paper in the grate bottom caught
> alight, I put the stove down on the ground.
>
> >>From starting the ignition of the paper to putting it down was about
7-10
> seconds I guess. Then I immediately put the pot of water on the stove and
> started the stopwatch.  This took about another 2 seconds.  From starting
to
> light the paper under the pine pieces until the pot was in place on the
> stove was about 12 seconds and I didn't time that part because it was
> impractical to do so.
>
> With the stop watch running, I balanced three paint cans on the upper part
> of the stove to increase the draft.  By the time I finished this process
the
> fire was smoking hard.
>
> I would have preferred to have the chimney in place, the pot covered and
the
> watch started when the flame hit the paper but I am working alone here.  I
> was recording the time the pot was on the heat and the 'head start' the
fire
> got was minimal.
>
> The fire shield around the pot was not present during this test which
would
> have increased the heat transfer to the pot sides, however the pot was
> encased by the chimney protecting it from any wind.
>
> I let it burn. The combustion 'went secondary' after about 45 seconds
> leaving me with substantially clean smoke and I could look down the paint
> cans and see the top of the water in the open pot, in theory.
>
> Unfortunately there was so much combustion product coming at me and what
> with the pot being underlit with a roaring red-fellow flame, and the water
> being in the dark, so I couldn't see the water surface.  I ran to the
> pick-up truck for a powerful flashlight to shine down and this allowed me
to
> take a peek occasionally.
>
> Before 1 minute 30 I heard the sound of boiling and I shone the light down
> through the fumes.  I could hear strong hissing and clearly see that the
top
> of the water was severely agitated but I was not sure if it was perhaps
> caused by the roaring fire and gasses passing around the pot.
>
> I let it run until the 2 minute mark and removed the three paint cans.  It
> was boiling vigorously.  I left the pot boiling without the extra draft
for
> another 30 seconds.
>
> At 2 minutes 40 seconds I removed the pot from the stove and placed it on
> the scale and let it stabilize.  I found that the water had come to a full
> boil and that additionally 80 gm of water had boiled off in that time of
> 2:40.
>
> +++++++++++++++
>
> Description of the Stove
> Name:    Basintuthu Single Pot Stove (pronounced bah-sin-DOO-too)
> Class:    Bottom lighting with preheated primary and secondary air
> Air Control:    None during this test.  All air passed throught the 5 x
40mm
> air control holes unhindered.
> Grate:    140mm diameter, 255mm long, cylindrical, open grated lower end,
> made from 1.2mm stainless steel.
> Pot:    230mm aluminum pot weighing 510 gm, tested without the lid.
> Fuel:    Pine, air dried in summer.
> Clearance between the pot and the fire passages:    25mm
> Fuel consumed during the test:    Over 200 gm, not sure exactly.
>
> +++++++++++++++
> END
>
>
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