[Stoves] Seeking feedback on a mixed-materials TLUD

[Anh Nguyen]

Dear Bodie,

Here are my observations, hope it can help a bit in your case.

Weak starting: if you light up the coconut shell directly, you may try to
change the top layer of the fuel to good dry kindling wood, it catch fire
and burn much faster.

If you have smoky problem when putting the pot on, you can check on 2
things:
- You got smoke through the whole burning cycle: you need more secondary
air/your pot raiser too low. Try to increase pot raiser.
- You got smoke only when the stove just burn for few minutes, no smoke if
put the pot on after a while: you put too much fuel and not enough space to
burn it. This happen to us a lot as most of the time users tend to over
load fuel to increase burning time. For your stove, you can try to reduce
fuel load or increase the space on top of the fuel canister.

Poor turn down ratio: please try to shut the primary air completely  (if
you have very flat surface on the PA door, can just put a brick, piece of
wood across to stop all/most of PA to get in) and the flame is still high,
probably you have problem with a large amount of primary air still get in
through the space at bottom of fuel canister. You can try to put a thin
layer of clay (1-2 mm) around the fuel canister when building the stove
bottom part. This will reduce PA to get in and help fix the fuel canister
in middle of the stove.

Some other points:

For secondary air: you may add some holes around the stove by putting a
small pipes when building up the walls to increase SA in.

Secondary air mixing: put some wood sticks/pipes (5-6 pieces) around the
smaller can when building up the stove. It will create some spaces that
allow more secondary air get to top part of the stove, it may improve the
mixing. I m not sure if this work but it is not very hard for you to try on
a clay stove.

Best regards,

Anh
GreenGenStove
Hanoi, Vietnam


On Tue, Jan 13, 2015 at 12:06 AM, Bodie Cabiyo <bodie.cabiyo at gmail.com>
wrote:

> Hi Fellow Stove Enthusiasts!
>
> For the past few months I've been working on refining a TLUD design
> (attached) which is fabricated from a mud mixture and recycled cans. My
> intention is to design a efficient, biochar-producing stove that can be
> fabricated by the user.
>
> I've gotten the stove to a point where it burns well under certain
> conditions, but I'm facing some serious roadblocks that I can't seem to
> surmount on my own. I would love your feedback.
>
> Here's the key problems I'm trying to solve:
>
>    1. Weak starting. With my primary fuel (coconut shells), it takes
>    about 2 - 4 smoky minutes for the stove to really get going and start
>    burning the smoke.
>    2. Poor mixing. A couple of weeks ago, Crispin described a "textbook
>    example" of poor mixing characterized by a column of flame that produces
>    smoke when the pot is placed over it. I presume that with better mixing,
>    the majority of the smoke would be combusted by the time it gets to the pot
>    surface.
>    3. Poor turndown ratio. As mentioned in the document, the stove has
>    two settings: high heat and very high heat. Even with a tiny amount of
>    primary air space, the heat stays very high.
>
> I'm eager to hear your comments! What do you think? Can I perfect this
> stove, or have I created a beast that can't be tamed? :)
>
>
> Thank you in advance!
>
> Bodie
>
> PS. You might notice the absence of a proper WBT. I haven't bothered yet
> because I feel that I should address the above issues first. If it would be
> helpful for assessing the design, I certainly can give the results of a WBT.
>
> --
>
> *Bodie Cabiyo*
>
> Professional: carbonalternatives.org
> Personal: concentricchange.wordpress.com
>
> *Food for Thought:*
> *"A mountain is composed of tiny grains of earth. The ocean is made up of
> tiny drops of water. Even so, life is but an endless series of little
> details, actions, speeches, and thoughts. And the consequences whether good
> or bad of even the least of them are far-reaching."*
> - Sri Swami Sivananda
>
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