A very different batch core, no riser at all

During the Innovators Event, I've built a mockup of a new core idea. Based on my experience with the earlier 45 degrees riser and the findings of Brian Livelsberger, also known as DCish on Donkey's forum. His experiment proved the double vortex could be formed in a number of directions, 45 degrees up being not the only deviation from vertical.

Of course I tried this at home beforehand and the results were encouraging.



I've made half a dozen videos of it and uploaded two to YouTube, here they are.





The second one seemed to be the better option although the double vortex looked much more chaotic. It was more like a fire fountain with smaller vortexes at the side and the end of the flames, dancing around all the time. This is much better visable in the next video, taken from the actual mockup build in Montana. This is done using insulative firebricks and sporting a very short chimney. In fact, this is the second version built at that location. It sports a glass top and glass front, both the inside of the firebox and fire tunnel are visable.
I hope you don't mind the sound track, it was too funny to replace it by a piece of music.



More about this later in the day.

Peter, you prat!

Sorry, but i had to say it!

Few years back, at donkeys, when you were just out of developing the batch; i asked you, if a firebox, with a round hole venturi on top and a heat riser above would work.

You said no! It will never work.

Max, I might be a prat but I was right about that. A riser on top of a firebox won't work, the double vortex won't form. In fact, at some point I tried a port and a riser on top but the flames went straight up and the thing smoked badly.

What I did this year is laying down the riser in horizontal position on top of the firebox, thereby creating a  90 degree corner for the flames to go through, a condition which is very important for mixing. The shape of the port is not round as you proposed but a rectangle of 50% instead, as a whole it is nowhere near your idea. A round horizontal tunnel on top like Pinhead described presumably creates a beautiful double vortex but I expect that won't give the results we should be looking for.
And second, the videos I've posted are the result of trying six different layouts and eight different secondary air channels. About two months of work off and on before the darn thing at last started to behave itself.

But if and when you think your idea would work, please go ahead and build it. I lean back and await the results, don't forget to generate Testo diagrams.

In order to make clear what the thing looked like, here's a very nice video made by Attilio Cesare. It'll provide a good view at the fire fountain from the top and might avoid possible misinterpretation.

https://www.facebook.com/attiliocesareguadagno/videos/10214437755916241/

The water was heated on the glass, I tried to toast a slice of bread first but that went black in about 6 seconds while I flipped it over every two seconds. Here's another video showing the water boiling, also one by Attilio.

https://www.facebook.com/attiliocesareguadagno/videos/10214436716370253/

The flue gases were tested using a Testo gas analizer. The results are a bit strange and not very consistent yet, in that the CO remains quite high (average 1165 ppm at best) but the white probe filters are dingy instead of the usual black.
This was done with a very simple floor channel in a smaller cast version inside my workshop.

Peter, sorry. I should have put a smiley with a big grin!

I'll have to find it to remember exactly what i asked.

I'll just digress. My idea of a round port, but a real plate or sharp orifice. Could may be work. A carburetor is not too bad at mixing gases usually.

Again, watch this.



Can you imagine a round top port. rather narrow.  And the flames develop in there, a bit like on the video. Or may be more like a nuclear mushroom. As usual. This is all babble. Your solution here is more interesting.

What you were teasing us with, made me think.  Is the vertical port absolutely necessary in a batch? I'm thinking of an horizontal port at the back, for example, 2/3rd up in the firebox, and à bit of horizontal "riser" behind. Another type of arrangement. But this could be really be useful in cookers.

Please, don't get crossed!

Gentlemen,
What are the air requirements and arrangement of intake on your ideas?
I.E. Port size =72%; primary air 20%, secondary air 5% (batchrocket).

Yes! This was incredible to witness as it happened!  Peter what are the dimensions of the tunnel or firebox as well??

Satamax Antone wrote: Is the vertical port absolutely necessary in a batch? I'm thinking of an horizontal port at the back, for example, 2/3rd up in the firebox, and à bit of horizontal "riser" behind. Another type of arrangement. But this could be really be useful in cookers.

What you propose here looks like what Brian Livelsberger did. He used a horizontal port higher up in the left wall of the firebox and led the fire tunnel to the front and up. In order to make a new arrangement, just take the existing batch box riser, port and all, and turn it on its side. I placed mine on top of the firebox but it could go anywhere although a riser that's going down would be a bit much to ask without a fan. In fact, a batch box rocket already has some features in common with a wood gasifier.

Travis Armstrong wrote:Peter what are the dimensions of the tunnel or firebox as well??

Travis and Kirk, I need to evaluate the original core for dimensions, I might do that today.

I recreated the drawing of the double shoebox mockup with glass on top, the videos of Attilio were a great help with that.
The dimensions are as follows, measured in millimeters:
Firebox 511 deep, 294 high and 200 wide.
Tunnel 460 deep, 170 wide and 180 high.
Port 176 deep, 64 wide.
Floor channel 50x38x2.5, ending halfway in the depth of the port. The original at home did use a 60x40x2 tube as the floor channel.



I have to stress that most of the dimensions are dictated by the size of the fire bricks, so when you intend to build the thing out of other bricks just use the pattern of the bricks as laid out in the SketchUp 8 format drawing which is available here.
All the dimensions are nominal, without calculating the seams. In case conversion of the dimensions to imperial is called for, here's a very comprehensive converter.
Air inlets used for this mockup were approximately 20% for primary air and 10% for secondary air when viewed as relative to a 150 mm (6") chimney pipe. When the whole of the core gets hot the primary air could be reduced to 10% so the air inlet proportion would be 1 to 1.

Peter, thanks for the hat tip! Someone over on Donkey's forum linked to this thread, and I'm glad I clicked through. I just had to register here to jump in on this thread. Since I don't have a testo, I'm excited to see how this will progress. I'm particularly interested in the difference between how the double vortex and the "fire fountain" compare. I have tried a round port (4" and 5" diameter versions, though I don't think I have documentation), and if I recall correctly, it created a quite turbulent result. I have a couple more ideas I want to try in my own setup, so hopefully time will permit more tinkering soon. Thanks, as always, for sharing your work!

Thanks for posting the SketchUp drawing Peter and for continuing the development of the batch box system. Please keep us posted with any updates.

Brian Livelsberger wrote:Someone over on Donkey's forum linked to this thread, and I'm glad I clicked through. I just had to register here to jump in on this thread. Since I don't have a testo, I'm excited to see how this will progress. I'm particularly interested in the difference between how the double vortex and the "fire fountain" compare. I have tried a round port (4" and 5" diameter versions, though I don't think I have documentation), and if I recall correctly, it created a quite turbulent result. I have a couple more ideas I want to try in my own setup, so hopefully time will permit more tinkering soon. Thanks, as always, for sharing your work!

The same documentation is also on Donkey's, see http://donkey32.proboards.com/thread/2341/different-batch-core-riser-all
At this time, the fire fountain is my favourite since the tendency of overfuelling is apparently stronger when inducing a proper double vortex, regarding this particular setup of course.
No thanks, my pleasure.

I skimmed through the pictures on my iphone and found some relevant ones. First shows Donkey viewing the flames in the thingy and trying to sniff some of the gases that're coming out of that redicously short chimney while Mud and Patrick taking pictures.



A very nice picture after dark while the thingy was running full tilt.



Later the next day I took it apart but beforehand Tomás and Patrick took pictures and measurements of it.



Four days later a new experiment was erected at Allerton Abbey, being a small cooking range connected to a bench of two half barrels. We tried to get it going on the last day without a proper chimney but to no avail, it was too much to ask. In order to have it started like that I should have added a bypass anyway, the whole of the build was soaking wet.



The fire tunnel was built like a U-turn to optimize space and have different temperature zones to cook on. At the bottom right of this rather hazy picture is the port with the floor channel end clearly visable. Above that there's the opening to the small bell and bench beneath. There's also a viewing window incorporated. The cooktop was cut with a wet saw out of the glass of a dumped induction plate.



To conclude, a picture of the design drawing which was made in one day. There are some glitches in there like some floating bricks and a bypass need to be added. Of course it could be built without the viewing window making the build less complicated and a better support for the glass cooktop as a bonus.



I will amend the design later in November and post it here, it is all done with US format bricks in mind.

I notice a peice of white material next to the viewing glass,is that ceramic board?

Yes, that's right. It's there to protect the red bricks from the highest heat. It's also a way to avoid having a significant step from the glass. It's all done very simple, of course it could be done using a steel frame to hold the cook top and incorporating the viewing window a bit more inside.

Finally, I got time to amend the drawing of the Allerton Abbey kitchen. It's a real world example, I'm convinced it should work given a proper chimney and bypass. A door is needed, although this isn't drawn. The air inlet should be around 35 cm² (5.43"²), placed low in the door. The bricks sizes are what was at hand in Montana, used in such a way minimal cutting was in order.
The drawing can be downloaded using this link.
It's in SketchUp 8 format, so most of the older versions should be capable to load it.

FYI:   more info about peter's build at allerton abbey is in this thread:

https://permies.com/t/72880/permaculture-projects/double-shoebox-rocket-cook-stove

Is there a formula for sizing up in dimensions? Say 8'' or 10'' systems?

Hi Sam;
Here is the chart for regular batch box's.

Going to Peters Batch rocket site might give you numbers on a riserless system.  http://batchrocket.eu/