Crispin and all,
The Prakti 2-pot unit should be directly compared with the 2-pot unit
from Envirofit.
http://www.envirofit.org/products/?sub=cookstoves&pid=5 (to see a photo).
Double-Pot Attachment
Features
* The Double pot accessory with chimney is the perfect add-on for
customers who want the portability and ease of using the
single-pot stove, but need the extra cooking area for large
families, festivals, or cooking for visitors.
* The attachment is easily moved onto or off of the stove for quick
change ability but is steady and sturdy while attached.
* The chimney portion can be used as is - to move any minimal
emissions out of the face of the person cooking - or can be vented
out of the home. * Shown with G-3300 cookstove.
And I am sure that there are other 2-pot stoves, but just not being
stamped out and with such smooth edges. Many of us have made such units.
What is needed is some serious study of these useful features, whether
built into the stove or as an attachment. Issues to be studied include:
heat transfer to EACH pot
types of pots used (sit on top or inserted)
insulation
temperatures of the outside surfaces
fuel efficiencies attributed to the second pot
And of course, the ways of supplying heat to the 2-pot stove
structure. The fact that both the Prakti and Envirofit units use
Rocket combustion structures does not exclude use with other combustors,
such as
TLUDs and even fossil-fuel burners.
Important note: These 2-pot structures both (virtually all of them?)
have a chimney because horizontal flow of the hot gases must eventually
have some upward movement to maintain the draft (exceptions if there are
fans in use). For the TLUD combustors, the chimney is a nice
enhancement of the draft.
I did not understand Crispin's comment about keeping the smoke and
flames together.
It seems to me to be worth investigation the % of smoke that can be
burned by keeping the smoke and flames together for a while.
That is true for "stick-burners" like the Rockets. But TLUDs are
"gas-burners" (that make their own gases in the close-coupled gasifier
reactors.) What would be the best ways to get the best results with
Rockets, TLUDs, or other heat sources?
Regardless, this seems like a great topic for some research by the now
"product-independent" laboratories for stove testing, such as CREEC and
Zamorano and ARC. But the question is: who will pay for these tests,
and who will release the results? Past practices have been that "he
who pays decides what will be released." And the chances of having
both PRAKTI and Envirofit pay and allow comparisons are about slim to none.
And I am not going to pay for it. And the testing centers get paid
nothing for testing unless there are sponsors.
So, I hope that the GACC will soon finance some comparative testings of
stove STRUCTURES that are not just focused on the combustion devices.
AND then do some testing of those same STRUCTURES but with different
systems of combustion, such as having Champion or Mwoto or Quad TLUDs
under identical 2-pot structures..
Happy New Year to all!!!
Paul
Paul S. Anderson, PhD aka "Dr TLUD"
Email: [email protected] Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
On 12/30/2012 4:24 PM, Crispin Pemberton-Pigott wrote:
Dear Richard in NW Obamaland
Agreed. I was looking at the size of the opening at the top and
wondering how it burned. I have been working on the use of flame tubes
a-la-BLDD6 and earlier versions where the fire is enclosed in a fairly
small round channel.
A couple of weeks ago I tried installing a 57mm I.D. flame tube in a
horizontal draft two-pot stove (I will add pictures later) to see if
the smoke could be burned post-pot-1. It worked pretty well. I do not
yet have definitive numbers but as a design approach it definitely
worked. There are a number of stoves that have far too much space
after the fire, allowing the smoke and flames to take separate routs
to the outlet.
So the stove in question has a huge outlet so if smoke manages to get
to a corner, it has ample space to escape to the margins away from Pot
2. It seems to me to be worth investigation the % of smoke that can be
burned by keeping the smoke and flames together for a while. There are
several stoves with a suitable layout for this. One is the three-pot
stove used in Indonesia consisting of separate clay round sections
with interconnecting tunnels. If the tunnels were reduced in diameter
to the point at which they became an impediment to gas flow, that
would maximise the chance of burning the smoke. If the flame was
entering the tube in the simple experiment I conducted, the smoke was
dramatically reduced showing a reproducible and consistent effect.
I really like the cast iron grate in the Prakti stove with a thickened
front bar that will resist banging from heavy wood sitting on it.
Regards
Crispin
Crispin,
This seems to be c similar o what was coming from the Dutch TOOL
foundation in (A ' dam) in the late 70's. They were trying to
replicate them thru our center (AATP) during that time but it never
really took on.
Richard Stanley
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
[email protected]
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/
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
[email protected]
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/
