[Stoves] Stove ID please - 2-pot stoves - testing needed

Tue Jan 1 12:09:27 CST 2013

Dear Paul,

I like the two pot stove concept (both pots on top of the stove, not
sunken, to accommodate different pots) because by decreasing heat losses
(insulating the flow path of the hot gases) and by increasing heat transfer
(using appropriately sized channel gaps under the pots and up around the
second pot) the one fire can boil water in two medium sized pots (5 liters
in each) at about the same time (around 30 minutes). The problem with a
stove that exposes only the pot bottom above the fire is that a small
percentage of the heat from the hot gases and goes into the pot (Shall we
estimate 20% or so?). That includes radiation and conduction.

If the fire is 4 Kw or so there's a lot of useful heat in the hot gasses at
a fairly high temperature to pass by the bottom and sides of the second pot
inside the skirt with an adjustable channel gap of 8mm or so.

The problem is that we spoil the design by using a chimney unless we go to
sunken pots. The chimney will take a disproportionate amount of hot gases
away from the second pot unless the second pot is sunken. Then the hot
gases can go up the channel gap inside the skirt before going down the
outside of the skirt and exiting out the chimney. Like other chimney stoves
the hot gases exiting should be below 200C as a goal: hot pots equal a
colder chimney.

The added draft from a Rocket combustion chamber assists the hot gases to
flow horizontally as does the draft created by the adjustable skirt around
the second pot.

This design has surprisingly less PM which might be caused by additional
scrubbing in the horizontal run?

All Best,

Dean

On Mon, Dec 31, 2012 at 8:06 PM, Paul Anderson <psanders at ilstu.edu> wrote:

>  Crispin and Dale and all,
>
> The topic is the 2-pot stove structure (from two commercial suppliers and
> for other sources).   And NOT the heat creation unit (which may or may not
> be built into the 2-pot stove structure).
>
> For clarification of this, lets be sure that Dale's wood-fire simulator
> (natural gas) is considered as equally appropriate as the heat source as
> would be the Rocket devices or the TLUD devices.
>
> Dale, this would be right up your alley.   Heat transfer.
>
> And this shows how good stove testing could be done by someone who is NOT
> a testing center.   And Dale should NOT be expected to do this work on his
> own time (unless he chooses to do so, with approval by his employer who has
> the equipment.).
>
> Do we (Stover community including all of the GACC Partners and GACC
> leadership) have a mechanism to get this task accomplished?   Perhaps some
> Stove Testing Center that gets a considerable chunk of money from GACC
> could sub-contract Dale (or other appropriate person) to get this job done
> for a relatively small cost.
>
> By the way, how much financial support is the GACC actually putting into
> the hands of the Testing Centers?   and with what requirements?    I assume
> that these are "transparent" transactions already done or soon to be done
> or at least being planned.
>
> And how can people like us Stovers with this very specific request
> actually get this testing onto the agenda in general and/or at a specific
> testing site?   This is certainly "technology neutral" and eligible to be
> financially supported.
>
> Imagine, if we had good data about these 2-pot "attachments", there could
> be some very beneficial results ready for anyone to implement.
>
> And are there already results in the hands of Prakti and Envirofit and
> others that would be useful if known by others?
>
> Paul
>
> Paul S. Anderson, PhD  aka "Dr TLUD"
> Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
> On 12/31/2012 1:16 PM, Crispin Pemberton-Pigott wrote:
>
>  Dear Dean****
>
> ** **
>
> Thanks for that clarification.****
>
> ** **
>
> Paul’s request for research into stove structures or types of structures
> is interesting in that stoves are not usually well classed as ‘structures’
> but rather ‘models’ of some prototypical stove design.****
>
> ** **
>
> Paul, I am not sure how you would design such research but it surely would
> have to include a well vetted evaluation method that gave results which
> could be used to interpret the structure as being the cause an improvement
> (or not).****
>
> ** **
>
> Given the 4 major influences: user, fuel, cooking vessel and the stove, it
> would be worth spending some time to design the experiment which would show
> that the stove (or structure of the stove) was the contributing variable.*
> ***
>
> ** **
>
> I suspect that Dale Andreatta’s wood fire simulator is one approach. If
> everyone recalls, he performed a number of heat transfer efficiency tests
> using multiple thermocouples and a standard gas-fuelled fire with a
> controlled gas flow rate.****
>
> ** **
>
> Regards****
>
> Crispin saying bye-bye to the Old Year****
>
> ** **
>
> ** **
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email addressstoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web pagehttp://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:http://www.bioenergylists.org/
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://www.bioenergylists.org/
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20130101/eabb6ccc/attachment.html>