Pablo Kulbaba

Can you tell me you favourite books on biomass burning theory?
Mine:
Van Loo, Sjaak & Koppejan, Jaap. (2008). "The Handbook of Biomass Combustion and Cofiring". Earthscan.
https://www.researchgate.net/publication/237079687_The_Handbook_of_Biomass_Combustion_and_Cofiring

Lehmann, Johannes. (2021) Biochar for Environmental Management: Science, Technology and Implementation, 2 ed. Earthscan
https://www.amazon.com/-/es/Biochar-Environmental-Management-Technology-Implementation/dp/0367779188

This looks very much based on Peter van den Berg's work with DSR and BBRs.
Given that work has been licensed under CC, why not give the right attribution ? There's no problem with acknowlegding that and selling the produce showed in photos.

On the other hand great deep diving in mass production, but first things come first.

Hi. This is an attempt to a collaborative post to list all standards related to wood burning heating appliances.

EN 16510 Residential solid fuel burning appliances - Part 1: General requirements and test methods
EN 13240 Roomheaters fired by solid fuel - Requirements and test methods. LINK

Nice!
Please tell me the name of those red bricks. How do you call the, over there? Here in Argentina they would be "Pressed bricks", or "Machine bricks".
How much do they cost each?

Hi.
This thread is to show you the Institutional Stove 50 liter model called "Poderosa" plans, hoping that you will get to know it better and take it into account whenever you decide your next build.
You can find full plans, with no paywall, in this link: Cocina Institucional 2024 "Poderosa"

The institutional Stove is a development of the www.aprovecho.com foundation.
I built my first institutional stove back in 2013, by reverse engineering the online videos published by Aprovecho. I was thrilled with its capabilities, although its appearance and features limit the field of application to a very specific type of user. Since 2013 to today I have built 25 of these kitchens and every time we turn it on, the public present is surprised by both how quickly the water heats up and how low the fuel consumption is. This kitchen boils 40 liters in 45 minutes using about 3 kg of wood.

See some of the pages that compose the package:



















In this video you'll see some images of a social project involving the build and installation of 10 of these stoves:

John Suavecito wrote:Yes, IMHO it is more efficient of overall char production per unit of biomass input.  I know some people love retorts because you can just leave them and they will go out on their own.  I get that.  That's not my priority.  I like making biochar and I want more char out of my wood that I have, and a larger quantity each time I make it.

John S
PDX OR

Great. You seem experienced in biochar. Let me be curious.
What size of pipe do you use in your barrel kiln?
What's your charring cycle duration? Since fire starting till water quenching.
What wood species do you char?

John Suavecito wrote:Thank you for sharing this design with others. I like the design in general.

What I do differently than this is I use a chimney with a larger diameter, and I burn the wood directly, without a retort.  The wider chimney allowed for much more efficient burning.  Direct burning produced a much larger quantity of char in the burn.  I needed too much char in my yard to make it in a retort.

That being said, everyone has to figure out a system that is going to work for their situation.

John S
PDX OR

Great to see hands-on opinions.

Would you say that that much larger quantity of char you get, goes along with more efficiency in char production? defining efficiency  in char production as weight of char obtained/ weight of wood input (taking into account the amount of humidity).

April Wickes wrote:Those are beautiful, Pablo. Thanks for the info and warning. Have you found any way to patch cracks?

I believe that cracks due to thermal expansion in masonry stoves are not patchable, because thermal expansion forces are uncontainable, irrepressible.

The only thing to be done (in my experience) with thermal expansion cracks is avoid them via several strategies:
-Use the biggest possible pieces of bricks.
-Thin mortar layer, less than 1 cm.
-Always lay bricks ¿interlaced? sorry, my english is not good. I mean the bricks in the next row are displaced from the current row.
-Metal has aprox the double of thermal expansion coefficient than bricks and mud, so always place ceramic wool between those two materials.

Pablo,
Could you expand (no pun intended) on the expansion forces? I saw several examples of Búbos Kemence while living in Hungary. It has a long, long history, and they must have a way to deal with those forces. What have you done to mitigate them in your projects?

Ok.
Danesa6 hornero 2020 was lower half made of bricks and upper half in 6mm diam rebar meridians and parallels,
then metal expanded mesh,
then mud+sand+straw

=CRACKS. Clients still in love with the result.

Danesa6 hornero 2021 the same as 2020
+1 layer sand+mud in fiberglass mesh 1cm sided hole
+1º jabelga (lime + sand in a thick paintable consistence) layer with fiberglass mesh 1cm sided hole

=CRACKS (more slight but i see them and that's enough). Clients still in love with the result.

Danesa6 hornero 2023 same as 2021:
+2º layer of jabelga with fiberglass mesh 1cm sided hole in certain areas.

=CRACKS (more slight but i see them and that's enough). Clients still in love with the result. I'm not satisfied and feel exposed to a geometry that doesn't allow me to give certainty to my clients.

My guess is the radius of curvature chosen where to tight and the pieces tended to get too small, and the masonry work didnt get so resistent as when the bricks are bigger, or uncut. The second geometrical disturbance was the profile thinning designed (my fault), because the slope was too tight in certain areas, and the resulting corbel  imposed a displacement of the bricks of more than the maximum 1/3rd of thickness that's rule of thumb.

April Wickes wrote:Pablo, that is a good and important question. I will not be able to answer it until January. However, I did make sure the plaster was reinforced with 2 layers of fiberglass mesh.

Great. I have experience with the same material. And the same application in round shapes. And let me tell you that i've found that thermal expansion forces are irrepressible.
But there's great joy and happiness in making round stoves.

Let me share with you some my stoves in this line of work:

Danesa6 hornero 2023




Danesa6 hornero 2021




Danesa6 hornero 2020