[Stoves] Increasing ND-TLUD riser height accelerates gasification and increases bed temperature

[Dean Still]

Hi All,

The problem with smoke at the transition from wood to charcoal forced us to
add so much primary (bottom) air that the charcoal then burned up resulting
in no bio-char. If we wanted bio-char, not using the charcoal for cooking,
we added a valve to turn off the bottom air. Not a big deal.

Yes, charcoal burns hot. But so does the fire in a TLUD. For long life we
had to use refractory ceramic or refractory metals.

Another problem was to shield the whole stove so it could be used in 20 mph
wind without smoking, etc. We chose 20 mph as a reasonable goal. The wind
shield ended up being a full length cylinder with holes around the middle
of the perimeter equidistant from the primary and secondary holes in the
interior stove.

Best,

Dean



On Fri, Dec 12, 2014 at 10:39 AM, Julien Winter <winter.julien at gmail.com>
wrote:
>
> Hi Paul;
>
> I stand corrected.  This is what you said to me a week or so ago.  You
> were suggesting a dynamic change.   I have been running static batch runs,
> and that colored my thinking.
>
> Paul Anderson:  "About height, whether of riser or of chimney:  I
> recommend some simple experiments when your unit is running.   Have some
> different lengths of extensions that can be easily placed (not even
> attached) on top of the current unit.   The additional draft will pull more
> secondary air and make the flame be LOWER as long as there is control over
> the entry of primary air.   But if the primary air is free flowing, the
> primary air will eventually "catch up" with the increased draft, and the
> flame will become higher than before.   If that is not what you observe,
> please let me know so I can adjust my thinking."
>
> I will have to give that a go.
>
>
> Regards,
> Julien
>
> --
> Julien Winter
> Cobourg, ON, CANADA
>
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