150 mm batch box cookstove w/ short riser

[travis]

Thanks.
Today I added a layer to the riser which made it about 70mm taller and I made it almost 250mm wide but had some trouble placing bricks properly through the cooking rings. I also added two small bricks as interruptions to the flow in the riser hoping for greater turbulence. I was getting a bit of smoke every time I would add fuel, now this has cleared up and it heats very nicely. My house was too hot!

[travis]

I forgot to say that I also widened the top of the risers new course to about 250mm, not precisely but almost. This has made the top gap slightly less but I have not noticed any poor performance. Flames do not come out of the riser like they used to. I also think that they may begin getting close to coming out because I open the top of the stove to see what’s happening which allows a new and easy exit for gases.

[Orange]

if you look at yasin's model it burns clean with the tiny riser. You can also add chimney damper to save energy since your system is not airtight.

can you compare wood consumption before/after? Exit temperature, condensation?

[travis]

Yasins stove has a much wider riser from the base all the way up at a consistent size. 240mm i believe. The wood I have been burning is quite poor because its mainly scraps from tearing the house apart inside. We bought wood but must buck and split it all. I can try getting my thermometer ouy when more ti.e is available. But i have very little equipment to really test efficiency.

[travis]

Oh and there is already a damper installed. I hope that it will run well for the winter.

[peterberg]

May 25, 2018 5:21:31 GMT -8 travis said:

Peter
The small opening is the bypass, the main opening to the heating wall is actually the old metal stove on the right side of the bell. I took the top cooking rings off and built around the stove and also left the door open. In the back of the stove the opening to heating wall is at least 200mm. This is mainly to try using the radiator system that is in the house.

Ok, that isn't the cause of the smoke then.

May 25, 2018 5:21:31 GMT -8 travis said:

Today I made two additions in the heat riser. One, I added about 70mm in height and also two small bricks in the ledges once the steps are above the port. These are very small intrusions into the flame path that I hoped would create more turbulence. The stove now seems to run with no smoke from the chimney even as the bricks I added dried out. Previously there would be several minutes after adding fresh fuel that there would be gray smoke from the chimney.

So the top gap is smaller now, 23 cm? should be no problem. A question though: has the stove been bone dry entirely before amending? Also, you made two changes and now it doesn't smoke anymore. Is that because of one (or both) changes or is it because it is dry now?
The riser configuration is now like a trumpet I'd imagine. What is the total height of it and what is the top gap size now?
Well done Travis, you've built almost certainly the first batch box rocket in Mongolia.

[travis]

Yes that should be correct, top gap is 23 or 22 cm. Have to double check. Yes the stove was dry before making changes, at least I think so. Not experienced enough to know for sure. Well after the changes it stopped smoking almost right away. I did not think of adding one change at a time. I could remove the bluff bodies from the riser and see how it behaves then add them back.
Yes the riser is like a trumpet from 150mm to 250mm and a height of 58cm.

[Orange]

yasin small cookstove is 160mm size entering into the bell. You have cast iron so I dont think it will warp from flames. Good think you lowered the ISA. Radiators now are colder now as they are not in direct contact with fire I guess. Btw, what do you do in Mongolia?

[peterberg]

Your riser height is now 53.5% of the recommended size (10B) and 66.8% of the recommended minimum size. It's looks like doable to build to me so this opens a good perspective to a lower kitchen range than before.
I don't have a clear picture where you added the bricks that're supposed to cause more turbulence.

[travis]

You don’t mean the riser into the cook stove part do you? Or from cook stove body into the bell?

I am in Mongolia first of all because I believe Jesus told me to come and live here, my faith is what brought me. Now I have been here for almost 3 years and have been planting trees of many kinds. I’m married to a Mongolian and work with her Dad. I have been learning to build rocket stoves in hopes of cleaning the air. As I have been here I’ve gained a passion for permaculture and living in a way that is similar to how the world naturally works when left alone.
What about you orange?

[travis]

I will try adding a photo to the dropbox folder to help clarify.
The other thought I had is to raise the fire box to whatever height is desired and use the top as a cook top and not enclose it in the bell then the riser does not matter. But it may depend on the constraints of each build.
My materials are also less than ideal. I used my mud fire box mix in the base of the riser to shape it but above that is red brick. I know many people would not do this but I want to know the longevity for people here in my area. The thought is that better insulative materials will most definitely give a cleaner burn, but not many would build one if that’s the case. 
I began wondering this morning though, if I was to mix up wood ash and clay slip would this be good for in the riser, similar to perlite?

[Orange]

well red brick is produced on temperatures around 1000-1200C so if you cover it with clay-ash mix it may be a long-term solution for the firebox and riser.

PS it may be better to discus this build in other thread.

[Orange]

that's a nice story! I'm in continental Europe so the climate is prety nice and there's plenty of wood. I like permaculture so I'm planting only perennial edible plants. If your stove works out it can be a model for other stoves in Mongolia.

here's a pic, riser is only 1 brick taller than firebox, no insulation:

[travis]

I made a few changes today to try and check what has made improvements in the stoves performance. I may have stumbled on something new. I haven’t read of anything like it the forums before (the last part of this)

So first with only the extra course in the riser- height 580mm, top gap 200mm. Burned well over all, when fuel was loaded it smoked for about 5 minutes then was quite clean. Could see a small amount of smoke/vapor through the main part of the burn.

Next I added only the top bluff body (split brick)which is sitting on the final ledge or shelf in the riser. This protruded into the riser roughly 60mm. The burn was very similar to the previous one, very little visible smoke or vapor after the first 5 min.

Lastly, I removed the small brick from in the riser and placed two bricks on top of the riser with an opening of 65mm by 250mm. Slightly larger than CSA of the system but smaller than the chimney. The top gap became 140mm. This was just to try it since it’s easy to access and change. It turned out that it seemed to be the best of all I’ve tried so far. It hardly smoked with new fuel and after the first part of the burn I couldn’t see anything coming from the chimney. I even climbed up to smell the exhaust from the roof and it had very little smell, maybe wet socks or wet charcoal. When I looked in the riser the base was all glowing orange and some of the p channel was glowing as well. Is this a too good to be true kind of thing? I can’t test with a Testo but it seemed to be the cleanest burn. Or is it bad because it will possibly be too much heat stress on the materials? I don’t have experience over the long term with this so any advice is welcome.

[travis]

Thanks Orange. I see what you mean. I was under the impression that his riser was 240mm. Quite oversized, but I guess not? Has Yasin left the forums?