Results of the 8" batch box thingy at the Innovators Gathering

Part 2 of full batch load of warm system.
sorry for the door being in the way in the second half.
If you wanna see the full load, after I load it all the way, then i pop the door down temporarily for full view and the video can be paused there to get an idea of how i load it and stacking / spacing.

I have been following this thread now for a few days. (took that long to catch up) I tried to read all of the posts on the donkey forums as well. I have a project in mind using an old wood stove with a side exit
flue. The flue is 6" diameter. The stove is a suburban manufacturing. has an air jacket for forced air as well. the bottom of the firebox is lined w/ firebrick.
So my idea is to shed the jacket and gut the stove to the very thin firebox. then, line the whole inside with the clay sand mortar and firebrick. in a similar orientation to the batch box. either remove the original exhaust flange from the stove or try to use refractory to line it. then it would exit into a perlite clay insulated riser and from there proceed like a normal rocket stove. Before i dump my limited time into this, i would like some feedback from the experts of the forum. basically, i want to know if it would be a total waste and i should just build the rmh from ianto's book, or if this has theoretical legs to stand on.

Peter van den Berg has done a lot of research into the exact dimensions and configuration that make the best batch box, and it is likely to be easier to build it from scratch with firebrick than to try to retrofit an existing woodstove. Of course, your stove might have just the right proportions to make this work, so it may be worth doing measured drawings to see if it would fit.

well that's very true. I think like the other innovators i'm just going to have to try this to see how it works. and make changes and improvements as i go .

If you don't have a stock by-the-numbers build to compare with, you will never be able to know if your experiments are successful. Getting "good" results doens't mean that it is superior to or even as good as others, or worth repeating.

Perhaps the hole in the door should mirror the shape of the hole at the back of the burn box. I'm thinking skinnier and taller but with a similar cross sectional area. This may help in a more even top to bottom burn.

So much work has been done in this space. It would help to go back and look at the threads and forums mentioned earlier in this thread. Besides, all of the batch gets roaring and burning evenly top to bottom as is. There is nothing to be gained past the current optimization and speed of burn as far as I can tell. Increasing the primary air intake csa will in fact make the burn less powerful and less efficient. Some of the pictures above snow the entire box full and raging like a blast furnace. What more could you ask for? And very pretty as well.

I may have been slightly misunderstood. I'm not trying to improve on Peters van den berg's batch stove. I agree hes put a lot of time tweaking this batch to run perfectly and by the way I love this idea. Watching the flames through the glass on this thing are phenomenal. I was just looking for opinions as to if you thought my idea would even work. Also after posting I realized I should have started a new thread instead of interrupting this one.
Gentleman please keep up the good work. I will continue following the batch box project very closely.

My opinion (not having built a batch box myself, just studying the published work) is that it may be able to work depending on the exact dimensions and proportions of what you have, but would most likely have to use less than optimal dimensions to fit and probably be more difficult than building one from scratch to proven dimensions.

Hi everybody!

Well, following this idea http://donkey32.proboards.com/thread/1568/batch-cooker


I modified Peter's batch sketchup drawing, to transform it as a rangetop and batch box accumulating oven.

If this can be usefull to someone.

Hello gentleman.
I am a new user and I would like, with your courtesy, to find out if it's possible ,glass ceramic to be replaced with a cooking hobs .Also I would like to know if it's possible to attach a bell and a water heater,
sideways, along the batch box.The water heater will be as a radiator, with power 12kw,so an approximate height and length of 1000mm .
That would be the size of such a firebox to heat water exchanger and a cooking plate?
Thanks.
With respect.

Some more pictures of the batch box rmh.






(Photo(s) by Art Held)

The riser is an 8" ceramic fiber tube, it could be shorter but it is being used as a whole.

Peter, how thick should this ceramic fiber riser be? I live in China and can get it custom made for about $60.

Dustin

Mine, a 6" version, is 30 mm thick, the wall thickness of the larger 8" duct is probably a bit more, something in the range of 35 to 40 mil.

OK, just had a weird idea - question...  has anyone ever tried to rifle the inside of the riser? What do you think the effect would be?  Reason I ask is that I am wondering if it would speed up the air velocity so that the second barrel in a double barrel system would burn hotter. I might need to do some physics on this one.

If you cast the riser in sections, then it would be possible, but the entire length as a whole, I don't see how I could rifle it.  So maybe cast like 10" section of the riser (so, riser 'bricks') with the rifling as part of the mold.

Cassie Langstraat wrote:Some more pictures of the batch box rmh.






(Photo(s) by Art Held)

How big is that building?  I am wanting to heat a 36'x48' insulated metal building on a 6" slab.

Danette Cross wrote:

How big is that building?  I am wanting to heat a 36'x48' insulated metal building on a 6" slab.

Late in the first page of this thread, Erica Wisner corrected Peter's metric to English mixup in describing it, and clarified the size of the space...

 
"I measured out the shop last year, it's about 50 feet by 30 feet in the main room, with about 2" insulation along most walls. So about 1500 square feet / 140 square meters. There's another room alongside the main room, about 10' by the full 50'. So about 2000 sf total, or something under 200 square meters.

-Erica W"


If you are heating for less frequent use/don't need continuous heating, this design is perfect as is.  If trying to heat a continuously used living space, the balance could be shifted in your design (after the heat riser,) away from immediate radiant heat from the stacked barrels over the riser, toward a heat storage mass in a bell or ducted bench of cob and or masonry.

 You could reduce radiant by removing one of the barrels in the two barrel stack, or could keep both and build up cob/mass around say, 1/2-3/4 of the barrel surface area, perhaps with the third facing "front" uncovered, for immediate people warming? As the barrels will be VERY hot, your first couple of inches should be lining it with highly heat resistant material like fire brick, closest to the barrel surface.

 Cob may be fine for the innermost layer on the barrels as well, but I am not 100% sure of that...

Matthew Goheen:  Thanks.  My building is similar, 36' x 48' insulated and drywalled. I am one of those that isn't crazy about the big metal drums. I am wondering if I could cast my bells from perlite and refactory cement and have them side by side rather than vertical.  If that building was heated I would be in it a lot more!!  I want to build my studio and workshop out there (I am a weaver, spinner, fiber type person).  I have been waiting for something to come along that makes a RMH feasible in sucha  large space without having to constantly nurse a fire.  This could be it!

You certainly don't need big metal drums for bells. If you want a different profile and less immediate heat, you can make a bell of bricks in whatever shape you want. I would not use perlite-clay, as that is intended for insulation, not mass, and is not very strong by itself. Cob is most assuredly capable of standing up to RMH heat from the core, though I would probably not use it as the only layer of containment.

Instead of barrels, i use home heating fuel tanks.

http://donkey32.proboards.com/thread/1817/starting-build-220mm-rocket-double

You can also find stainless steels ones, for foods, in large shapes.

Satamax Antone wrote:Instead of barrels, i use home heating fuel tanks.

http://donkey32.proboards.com/thread/1817/starting-build-220mm-rocket-double

You can also find stainless steels ones, for foods, in large shapes.

I want to stay away from metal if I can.

If appearance is your source of dislike for metal barrels or other metal chambers, they can be covered with cob, brick, and or other masonry, which would improve the appearance, and shift the balance away from immediate heat radiation toward absorption and slow release from the masonry mass covering the barrel and/or bells...

Matthew Goheen wrote:If appearance is your source of dislike for metal barrels or other metal chambers, they can be covered with cob, brick, and or other masonry, which would improve the appearance, and shift the balance away from immediate heat radiation toward absorption and slow release from the masonry mass covering the barrel and/or bells...

Well, it's not only the look, but I wonder how long barrels have lasted over the long haul?

As long as they are not actually IN the heat riser or burn tunnel areas of a stove, The metal of a standard 55 gallon drum can last a long time...  Think of the body of a wood stove...

 In the bell that is actually over the riser ("the barrel") corrosion of the top could be an issue long term... The better performing and higher btu output of the stove, and the closer that barrel top is to the top of the heat riser, the more of a problem it would be.

And it could definitely be more of an issue if it happened AFTER you built masonry/cob all over it.

 So perhaps your inclination to go with masonry only is the best thing for your situation.

I like the idea of some radiative/cooking surface like the barrel top,  and of course would want the awesome ceramic stove glass window on top of the firebox, which would give a good amount of direct radiated heat (though mostly upward, I would imagine...)

Could also do masonry for the sides of the first bell and a piece of steel plate as a removable lid for the top (with proper gasketing, and distance from the top of the riser to reduce warpage/increase even-ness of heating,  of course) which would make checking on/cleaning the area inside the "barrel" easy...

 With masonry, I believe I've read that the area of the first bell/barrel at and above the top of the riser needs to be firebrick (the heavy/not so insulative/expensiv stuff) and then regular brick can be used past that point... For areas of the bell below that/past it in the exhaust stream, and subsequent bells pretty much any type of masonry unit can be used.

And of course, cob...

Where in the building would you like to locate the heat?  Would you use it for purposes like heating water for dye making/setting?  Wold the Walker stove fit with your needs with perhaps a bench for heat storage instead of the oven.?

Hans Quistorff wrote:Where in the building would you like to locate the heat?  Would you use it for purposes like heating water for dye making/setting?  Wold the Walker stove fit with your needs with perhaps a bench for heat storage instead of the oven.?

That is exactly what I want in the kitchen, plus a nice big RMH for the main heat of the future house. Thanks for this!!

Danette, i have a cast iron firebox top. Takes a while to heat. But at the end of first load, i can Cook on it. And a glass door.

Check chimney retrofit and vertical batch threads at donkey's. There's few sketchup drawings that i have made. Which include a cooking plate.

Satamax Antone wrote:Danette, i have a cast iron firebox top. Takes a while to heat. But at the end of first load, i can Cook on it. And a glass door.

Check chimney retrofit and vertical batch threads at donkey's. There's few sketchup drawings that i have made. Which include a cooking plate.

Great! Thanks.

It has now been three years and Peter makes a summary about this project.

To see the full build, check out the DVDs.

a bit about this build

i just bought the Wisner book, and I'm hoping they cover how long a barrel over the riser will last, and how long other materials can be expected to last!!

Nobody really knows how long the RMH barrel in a dwelling or dry shop will last, because the oldest (20 to 30 years) are still reportedly working. For the combustion core, hard firebrick as the Wisners use will probably last numerous decades, though the first brick in the burn tunnel roof sees exceptional thermal stresses and may fail sooner. That is about the most accessible for replacement, though. Other more insulating but soft components will give higher performance but may have shorter lifespans.

It would be wise practice to build your RMH with the core accessible for inspection and possible future repair. This can often be done without tearing up the casing if planned right.

Glenn Herbert wrote:Nobody really knows how long the RMH barrel in a dwelling or dry shop will last, because the oldest (20 to 30 years) are still reportedly working. For the combustion core, hard firebrick as the Wisners use will probably last numerous decades, though the first brick in the burn tunnel roof sees exceptional thermal stresses and may fail sooner. That is about the most accessible for replacement, though. Other more insulating but soft components will give higher performance but may have shorter lifespans.

It would be wise practice to build your RMH with the core accessible for inspection and possible future repair. This can often be done without tearing up the casing if planned right.

Glenn,
thanks.  Do you think fire brick is more durable than the ceramic fiber board used in Matt Walker's cores?

I don't know how durable the ceramic fiber board is; hard firebricks can last many decades outside of industrial-grade service.

Glenn Herbert wrote:I don't know how durable the ceramic fiber board is; hard firebricks can last many decades outside of industrial-grade service.

thanks Glenn.  I always had a vague and somewhat scary vision of the top of my RMH having finally deteriorated and blown a hole one wintery day, and rocket flames shooting up to the ceiling and doing who knows what? after using the RMH accident free for 20 years.


on a slightly different note...

I don't know how the efficiency of a rocket mass heater would compare with the efficiency of the clay plastered brick (masonry) 'bread oven' and smaller oven made of clay tiles in the kitchen in this sustainable home in Latvia , but again, I see that rocket mass heaters are at least 9 times more efficient than the most efficient conventional wood stoves, as explained in https://www.youtube.com/watch?v=t0cs8PWDfwg]this video.  Who knows, perhaps the Latvian builder utilized rocket technology in his masonry 'bread oven'?  But from looking at the pictures, I doubt it.  


https://drive.google.com/file/d/1fr9GSidHi5k8Tnvs23DbefSqhQzG55cO/view?usp=sharing
https://drive.google.com/file/d/1Ju0bjIk1F6Wdz-dotKyE0IsA5M6gkW21/view?usp=sharing
https://drive.google.com/file/d/1Xth4txAJiaR440PdA_FCbzteZZUynkti/view?usp=sharing

 
In the builder Jacob's words... "Exterior measurements of the house is [21.33 feet] x [42.65 feet]. Living space in both floors are [1,292sq/feet]. The house is being heated with clay plastered brick bread oven and smaller oven made of clay tiles in the kitchen (the picture above is of the larger of the two - the bread oven).  To heat up both floors of the house, when outside it is [-14 degrees Fahrenheit] only [the] small oven is heated once a day.  When freeze gets below [-5], we heat up the bread oven.  Once it is heated, because of it’s thermal mass of 5 tons, it keeps the warmth 2-3 days. To heat up all the house in the winter time we use not more than [1.1 cords] of dry firewood."

There must be something really Latvian-saavy about his design, if he only needs to fire it up every 2-3 days!  Another large masonry stove built by the author of https://www.motherearthnews.com/diy/building-a-russian-woodstove-from-bricks-zmaz97onzgoe]this Mother Earth News post, is almost 3 feet x 6.33 feet by 7.5 feet high, and the firebox is 40 inches long. I'm not sure where this author lives, but I'd be surprised if his winter temps are lower than -5, and he says they have to fire it twice per day (morning and evening).    The Mother Earth news blogger didn't say how many tons his bricks weighted, but Jacob's total bricks weigh 5 tons, as stated on his website.  Granted, this builder used a masonry stove design from a library book, but the size of his stove at least sounds somewhat comparable to Jacob's Latvian masonry stove, doesn't it?  As the two designs appear to be somewhat similar in size, the amount of bricks (thermal mass) used in the design only seems to be partially responsible for the efficiency of Jacob's masonry stove.

Any thoughts?  Also, I does anyone have links for the two types of brick recommended (fire brick and 'regular brick')?  I wanted to do an estimate on how much it would cost to get the amount of bricks for various designs, but i'm not sure what kind of bricks really are optimum.

All the best.  I can't figure out why the URL's aren't working correctly...i mean, I didn't want to pos the whole URL....just the URL description!  eeeek!

Some pics of it being started properly:

Hi Peter, Thanks a lot for sharing your result generously.

If I may ask a question? Based on your previous and present experiments can you conclude that a bigger system, in general, has less CO emission than smaller ones?


Julian