[Stoves] "Vom Pyrolysekocher zur terra preta" Workshop 11-12.06. --> Clay TLUDs

[Rebecca A. Vermeer]

Dear Julien, Werner and All, 
Attached are the Babylon English translations of Werner's German email and Workshop  Agenda.  It looks very interesting indeed! 
  
With the small version of  Eco-Kalan Bingka Oven, I had experimented with the clay-rice husk-molasses mixture at various proportions.  At low proportions of rice husk, the mixture can still be formed into the oven components but with negligible impact on the weight.  At higher proportions, the mixture can no longer be formed or shaped into a Bingka oven -- mixture no longer stick to the cement mould.  Even at low concentration of rice husk,  the durability of the fired Bingka oven is poor.  For example, the posts that hold the heating plate  above the bottom of the oven easily breaks off from where they are joined. 
  
In looking at the Artefact's stove (pyrolysis chamber), it seems that a fibrous organic matter has been added to the clay.  Werner -- would you be able to share your recipe for the mixture?   does the fired pyrolysis chamber crack (even small cracks) during pyrolysis?  Many of us would love to know. 
  
Best wishes, 
  
Rebecca Vermeer 
  

----- Original Message -----

From: "Julien Winter" <winter.julien at gmail.com> 
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Tuesday, May 3, 2016 9:44:25 AM 
Subject: [Stoves] "Vom Pyrolysekocher zur terra preta" Workshop 11-12.06.        --> Clay TLUDs 

Dear Werner; 

Good luck with your workshop.  It looks very interesting. 

However, I am interested in the picture of the TLUD reactor in your pdf attachment.  Can you provide details on its construction, and who designed it? 

Clay TLUDs could be very important in communities were imported materials (i.e., metal) are very expensive.  Clay TLUDs could maintain the self-sufficiency in cooking that traditional stoves provide.  The method being used in Haiti (Jon and Flip Anderson) and Bangladesh (Mahbubul Islam) is to mix clay and organic material (1:1 by volume), where the organic material is sawdust or rice straw, plus cow dung.  After the stove has been formed, the interior is polished to seal pores, and may also be lined with clay slip.  This method is already part of the existing skill-set of some artisans in Bangladesh. 

The organic mater in the clay becomes a pyrolyized "fugitive" creating porosity, wherever the temperature is high enough.  In any case, organic makes the stove body a poorer conductor of heat, with a lower heat capacity than solid clay.  Porosity in the stove body also makes the clay more tolerant of thermal expansion. Because the stove body doesn't conduct heat as well as solid clay, the inner wall of the combustion chamber may become vitrified. 

A similar approach was taken by Clayton Bailey (1971) “How to Do Horseclay Firing Without a Kiln”  with his self-fired clay pottery.  He used 50% horse manure in his clay body. 

What is needed is to know more about the durability of clay TLUDs and the range of clays from which they can be made. 

All the best, 
Julien. 

  

-- 
Julien Winter 
Cobourg, ON, CANADA 

_______________________________________________ 
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://stoves.bioenergylists.org/ 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20160503/1d0764d6/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ARTEFACT TERRE PRETA WORKSHOP EMAIL-ENGLISH.docx
Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
Size: 11280 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20160503/1d0764d6/attachment.docx>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Herde-Workshop2-english.docx
Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
Size: 257859 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20160503/1d0764d6/attachment-0001.docx>