fireplace to batch box conversion

[satamax]

permies.com/t/38889/a/44150/yomegastove2.skp?download_attachment=true

Well, another version, with a plunger tube, and a better cooking plate. The plate is part of the top of the bell.

[yhomega]

Thanks for the sketchup!
We thought that a wood storage place would be good, I will try to add that to your design.


The plunger tube it the chimney right? I plan to make it even a bit lower, because I have a existing ash collector down the fireplace. I will be carefull to keep a CSA of 6'.


www.leboncoin.fr/bricolage/1027770647.htm?ca=21_s
He is living just next to me, I will buy the bricks next week (0.75 each or maybe a bit less)
Do you think I can use thoses bricks for the riser and insulate with rockwool?


Also I will go single skin, the builder is confident that with refractory brick it will be safe enough. Also it will be a bit cheaper/easier to build

You told me that 15cm room above the riser is ok. Do you think that a 100cm (instead of 108) riser with 15-20cm room above would work?

Thanks for all your precious help satamax

[satamax]

Plunger tube, is an extension downwards of the chimney tube, to augment the height differential between top of the bell, and bottom of the bell. Hence, keeping more heat. Keep 10cm bellow the tube in this case. 5 is about right for the CSA of 314cm², in case of a 20 cm riser. Which i've drawn since i had the parts ready in another sketchup.

I made my first design a single bell, with several channels. Better to heat the cooking plate. Three vanes could be added; to block the cooking plate from heating, and also make a bypass for hard cold starts. I think you can count on 170C°/180C° on the cooking plate.

And Yep the bricks would do. Tho, it will be slow to heat up and work properly. It will be smokeless in five minutes. But take far longer to have that heat catalyst effect, or a glowing riser. Mine, is about 2cm thick, and takes longer than i like to warm up. Up to the point i have made the ramps out of insulating firebricks lately.

[peterberg]

Oct 8, 2016 0:42:07 GMT -8 satamax said:

Plunger tube, is an extension downwards of the chimney tube, to augment the height differential between top of the bell, and bottom of the bell. Hence, keeping more heat. Keep 10cm bellow the tube in this case. 5 is about right for the CSA of 314cm², in case of a 20 cm riser.

Hmmm... That 5 cm is the absolute theoretical minimum. However, the gases need to go through a 180 degree direction change. From vertically down to vertically up, I would recommend at least 10 cm in this case, a 100% increase.

And another very important point: when the plunger pipe is leaning against a wall the gases can't enter from behind so about one quarter of the circumference of the pipe isn't used by the downwards directed stream. In this particular case the minimum allowance under the pipe should be 6.7 cm, plus the 100% increase mentioned above is 13.4 cm.

A plunger pipe in a corner is even worse, half of the circumference is blocked by the two walls in this particular situation. Taking this reasoning further, the open space below the pipe should be 20 cm is this case.

Every batch box rocket that appears to have a slow pulse like a steam locomotive when running flat out is sporting a restriction somewhere. Very, very often it turns out to be the placement of the exhaust opening. My own experiments all showed this behaviour until I found out the reason behind it. The development builds after I found out this possible bottleneck didn't show a pulse anymore. Including my own house heater and the 20 cm builds at Permies in Montana and at the MHA in North Carolina, both in 2015.

[satamax]

Yes Peter; i said 10cm minimum. Tho, it seems soo obvious, that i often forget to insist on the subject.

Absolute ideal situation, i reccomend 150% minimum, for a batch with a cooktop. Otherwise, more is better. I like teh bell oven aranhement in this drawing. May be the first one i did like this was for one of our Italian members. After or before i built my workshop rocket. I have the same arangement in the "barrel" radiator. I bet i could cook pizza in there. I have to give it a try now that i sealled the door a bit better.

But having the metal barrel in this spot is not good imho. Better to have mass, for the oven, and to release slowly the high heat stored. And cool the gases further down the line, with a cooking plate. This is not far from what i'm planning for my future flat. Obviously, i will try top load before it goes in there.

[peterberg]

Now you mentioned your future flat: is it habitable before this coming winter?

[satamax]

Oct 8, 2016 6:34:16 GMT -8 peterberg said:

Now you mentioned your future flat: is it habitable before this coming winter?

Camping like, i would think so.

[yhomega]

goo.gl/photos/nCdKiNPdWinS115H7
Here are the bricks for the bell, total 300. I think the maker is valabregue.wixsite.com/valabregue or it was one of his competitor (same area, bollene)
some bricks have some cracks, I hope it's ok

I have an extra square meter of firebricks from an electric accumulator heater just in case it's not enough.


On monday I give a call to prosiref and order 50 IFB.
I don't know if Classe 23 or classe 26 is better. I think classe 23 isolate more but has lower heat resistance
www.prosiref-boutique.com/-classe23--171--a.htm 
www.prosiref-boutique.com/-classe26--173--a.htm

[satamax]

Use the cracked ones on the inner skin. At the bottom, where it's not too hot. And the firebricks from the accumulator at the top, if you can. Because they're wonderfull at storing heat.

Type 23 is suficient iirc. www.prosiref-boutique.com/-classe23--171--a.htm

[yhomega]

Some update!

goo.gl/photos/Bw6XB9WffDoZ1UBCA

I received from prosiref :
50 brick Classe 23
10 isolating bricks (not suitable for firecontact)
2m of rope gasket (fiberglass)
25kg of refractory mortar up to 1500° for the core

I received a gun infrared thermometer

I bought at leroy merlin5*1m stainless steal 6' pipe.
100kg of refractory mortar up to 900° for the wall

I made a finishing plate to put on the top existing chimney
For the damper I will do it myself

Im also planing to buy a CO and smoke alarm/detector to put inside my living space. I'm trying to source a cheap stove door so in case of maintenance I can quickly check inside the bell.

Final design should be something like this :



-really small heated bench. Could be used for wood storage.
-oven door is on the back side
-'plunger tube' for the chimney
-batch top loading
-batch box is regular 6' design (not a sidewinder)
-Coper pipe for water heating molded around that :


Builder is coming next week, let's go

[satamax]

Hi Yhomega.

Well, one word of caution, carefull if you dump the stove pipe down in the ashes pit. There might be not enough roop between the pipe and sides of the hole for the gases to flow. You'll have to measure.

[yhomega]

goo.gl/photos/xuB8E3bNK1XJnf9y5

I cut the insulated fire brick today, really easy.

You can see the small channel under the bench and the opening on the ash pit. I will do a big opening in the stainless steal pipe and it should be fine, I will post picture when it's properly done just to make sure

My issue is more the size of the mass heater. A 6' is way too big in the middle of the room
A 5' is a bit better, but still it's big!

I think I'm gonna move the old fireplace against the red wall (after installing a fermacell wall...) and build the batch box there.
Well it's more work but if it looks much better I think it worth it.

Difficult to choose :/

[satamax]

Yhomega, what would you pût where this chimney is now? If you don't have a plan, leave where it is. You might even have to repair the tiling. And you won't have to build another chimney.

[yhomega]

goo.gl/photos/8ebjrNJidWKBmWYy5

The build has started, thanks to Jack (experienced builder) and Felix for the welding!

I have 2 more questions please (yes I know, too many questions already)

The fireplace has been moved against a wall, height is not an issue anymore (before, too high would have look weird)
I can fully respect the riser length and keep 30 cm room above.


Before the chimney would have done 4.5  meters verticaly (down the floor up to the roof).
Now It has to do 3 meters vertically 3 meters horizontaly (to get to the old chimney) then 1.5 meters up to the roof


Question 1 : Do you think I should isolate the chimney with rockwool? (above the ceiling and/or inside the old flue)





In the futur I would like to be able to heat water. I have this steal basket that is high in the bell (=high temperature) and offer good thermal conduction.


I think I could use a heat exchanger stick to the black basket but Im not sure how to do it safely. I tried to source more information online but nothing reliable. batchrocket.eu/en/applications#chb is not fully documented. how to avoid issue in case the heat exchanger run out of water? the pump stop?

Question 2

How would you heat water safely with my design?!


Cheers

[yhomega]

goo.gl/photos/aEPuhUBoqpxZzkV66
here is a bunch of pictures during the build.
Still few more bricks to install, and the top to let dry.
Can't wait to start it