[Stoves] Length of wood segments vertically placed Re: Recorded EPA webinar and files posted/ wood size

[Paul Anderson]

Lanny and all,

The wood you describe can be called "segments" (in contrast to 
"stickwood" of greater and irregular length, or chips /chunks that are 
so much shorter).

In Uganda we regularly use wood segments that are 18 - 20 cm (nearly 8 
inches) long because that size fits well vertically in the Quad TLUD 
stove by Awamu.

No problem with rapid burning when the batch is top-lit.   But the 
segments should be snugly packed.   And in the case of any large 
vertical gaps, some chips or even charcoal pieces can be added to the 
fuel BEFORE ignition to minimize the difficulty of the fire (embers) 
dropping down to the bottom of the batch of fuel.

Also, I have an unsubstantiated hunch (observed but not studied) that 
even when the fire moves down one side more than uniformly migrating 
downward, the heat of pyrolysis does move laterally (still rather slowly 
and with very controlled supply of primary air).

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.com

On 9/22/2013 8:39 PM, Lanny Henson wrote:
> I would like to see wood at least 15 cm/6 inches long being used in 
> future test.
>
> I noticed the size of the wood In the test is 2 x 2 and  2-7.63 cm 
> long. That translates to about ¾" x ¾" and  ¾" to 3" long, for my 
> fellow "meterphobics" (unnatural fear of the metric system)
>
> 7.63 cm is very small wood and It takes a lot of work to cut wood down 
> to that size. It is not the diameter that is a problem because wood is 
> easily split to smaller diameters but the length of  ¾' to 3" is a 
> problem because the cross cut is more difficult.
>
> I have seen comments that users do not like to cut wood down to small 
> pieces so I wonder how practical a household size stove is going to be 
> unless it is flexible enough to burn larger size wood.
>
> Even 15 cm may be too short for some end users. If I am wrong about 
> the small wood problem please let me know.
>
> The problem with designing a  batch-fueled stove that will burn 6" 
> long wood, is that it is more of a  challenge than a stove that will 
> only burn wood  3" long,  because the size of the burner needs to be 
> different. Wood needs to lay horizontally with the grain when being 
> burned in a batch, because wood does not burn well standing on the 
> end.  It reacts all at once and the burn is not steady and continuous, 
> like it is when the pieces are laying horizontally. Laying 
> horizontally and top lit the pieces burn a few at time as the flame 
> burns down through the fuel bed in more steady way, with less heat 
> spikes and dips.  The taller the stack the better for the same reason.
>
> I am working on a burner that will hold 1Kg of 6" long wood. It is 
> oval to hold the longer pieces but narrow so the wood will make a 
> taller stack. It burns the wood from both ends and there is no grate 
> or even a bottom to the stove. This is very handy for saving the 
> charcoal, just lift the stove off and lay a cap over the pile of 
> charcoal on the ground to extinguish it. When I am able to walk again 
> I will take some photos
> Lanny
>
>
> ----- Original Message ----- From: "Jetter, James" <Jetter.Jim at epa.gov>
> To: <stoves at lists.bioenergylists.org>
> Sent: Saturday, September 21, 2013 5:35 PM
> Subject: [Stoves] Recorded EPA webinar and files posted
>
>
>> To All,
>>
>> Thanks to those who joined us for the webinar on August 29, and 
>> thanks to the Global Alliance for Clean Cookstoves for hosting.
>>
>> The recorded webinar, presentation slides with notes, and draft 
>> spreadsheet have been posted for your information, review, and comments:
>> http://community.cleancookstoves.org/communities/forums/viewtopic/22/33/207?post_id=357#p357 
>>
>>
>> The purpose of the webinar was to:
>>   Provide an update on the EPA cookstove testing project
>>   Present a format (EPA spreadsheet) for sharing data
>>   Discuss test methods
>>   Focus on example testing results for a batch-fueled pyrolytic TLUD 
>> (top-lit up-draft) stove
>>   Solicit further comments on methods, spreadsheet, and data sharing
>>
>> Please let me know if you have any further comments by Oct. 11. My 
>> email address is: jetter.jim at epa.gov
>>
>> Regards,
>> Jim Jetter
>>
>>
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>
>
>
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