Stove Design help needed

I have created a rough draft (attached) of how I think the stove will fit best into my sunken floor living room.

The step down into my living room is 40cm and is 4M long. If I make the heat battery (bench) 1 meter wide this will provide me with 4 Cubic Meters of mass.

Will this work? Can I use 2 runs of 6 inch stove pipe?

Is it possible to build a cinder block retaining wall to enclose the thermal battery? Can I use building sand for the thermal battery and put floor tiles on top to match my existing floors?
How long 6 inch stove pipe should I use for the feed tube? Heat riser? Burn Chamber? Can I insulate heat riser tube with Rock Wool packed in between the 6 inch heat riser tube and a larger 10 inch stove pipe?

Thanks in advance for helping me with this project.

Adam, first of all, metal is doomed (for the parts in contact with fire.)

You can use stove pipe as a form for cob mixes. But you can't make a heat riser, in a properly working rocket, out of steel with insulation which is not self supporting.

Use clay chimney flues , half firebricks, vacuum formed superwool. Vermiculite boards. But not steel. Bricks are preferable for feed tube and burn tunel. The feed tube and beginning of the burn tunel is better made out of dense firebricks. But after, you could also use insulating firebricks, which are fantastic for this type of aplication. For your flue, you can use your step as a bench, no prob, tho the pipe should not be paralleled as it seems it is on your drawing.

Cheaper and better yet, use the half barrel system, to form a bell.

http://donkey32.proboards.com/thread/560

http://donkey32.proboards.com/thread/609/heated-seating-nyc-restaurant

http://s65.photobucket.com/user/mremine/library/NYC%20Rocket%20Stove%20Build/#/user/mremine/library/NYC%20Rocket%20Stove%20Build/?page=1&_suid=1388141541234008031606022527948

This looks exactly like what you want to do.

Mind you, sand is more of an insulator than a thermal mass.

The best options, for heat transfer and capacity.

Concrete

then Cob,

Then pea gravell (or a smidge bigger) and rammed earth.

Then sand.

I don't think anybody here has tried fist sized pebbles as of yet. This one is tricky, because it relies on both conduction and convection. But my gut feeling says it should be another solution.

Over concrete, cob, pea gravell, rammed earth and sand, you sure can use tiles. May be i would use some sort of acrylic caulking for the joints, not knowing what the dilatation willbe like. Or just use a grout, but be prepared to redo it in the future. On ramed earth, pea gravell and sand, i would pour a little floating slab to be abble to fit the tiles properly.

For a six incher, usualy 34cm for the feed tube, 18cm for the burn tunel, and between 70 to 1m depending on your barrel arangement.

Another thing, you'd better raise your chimney above the peak of the roof, or at least half way between eave and peak.

Hth.

Max.

Thanks Max.

My stove pipes are tin and are really inexpensively made locally. I can have them made in any diameter but I figured that since I only have 35cm (17.7 inches) between my tile floors and the top of the step and only 4 meters long, I thought I would split the pipe into 2 and run them parallel the full length recouple them and go up 2 meters then turn 90 degrees and out the exterior wall (no roof overhang on that side of the house).

The total size of the "bench" will be 35 cm high, 1 meter wide and 4 meters long which is 3,5 cubic meters. Will that work?

Can I build a retaining wall from cinder blocks and fill it with crushed gravel or tuff (lava pebbles) instead of sand - burying my 6 inch tin stove pipe?

The tiles are synthetic ceramic and are on a bed of sand with a 1 inch layer of concrete. Do I need to insulate my tile floors from the heat of the bench?

Lava rocks is insulative.

Again http://s65.photobucket.com/user/mremine/library/NYC%20Rocket%20Stove%20Build/?page=1#/user/mremine/library/NYC%20Rocket%20Stove%20Build?sort=3&page=1&_suid=1388291371062032609531579630374

For the feed tube stay away from metal, Ernie, Erica and Paul have all said that it has failed everytime they have tried it. Reason being, it heats up and acts like a little riser therefore fighting the suck of the riser.

Tyler Flaumitsch wrote:For the feed tube stay away from metal, Ernie, Erica and Paul have all said that it has failed everytime they have tried it. Reason being, it heats up and acts like a little riser therefore fighting the suck of the riser.

Well, not necessarily.

It could be cooled like a P chanel. Tho, i'm not keen on metal where the fire takes place. And bricks or clay ends up heating, and doing the same thing. Only slower.

Tyler Flaumitsch wrote:For the feed tube stay away from metal, Ernie, Erica and Paul have all said that it has failed everytime they have tried it. Reason being, it heats up and acts like a little riser therefore fighting the suck of the riser.

Hi Everybody -

What about a ceramic thermocouple protection tube as the riser? I realize thermocouplers are typically used for electrical purposes, but I just now found this online, and it looks ideal (I've attached a picture as well) --

http://www.omega.com/pptst/PTRA_PTRM.html

These tubes can operate at serviceable temperatures to 1500C (3450F), and they can be had in 4", 6", 8", 11" and 12.5" diameters, up to 24" long. Perhaps a 24" and a 12" can be coupled as a 36" riser.

Anyway, I need to find something that will work. For this application, I need to the stove to be modular, portable, lightweight, and I haven't the luxury to support a thermal mass. I am relying only on the rocket stove as a heating unit. Right now I am looking at the unit being two components -- the barrel as the top and the burn chamber as the bottom, plus the flue out the back of the barrel.

Kevin Prata wrote:

These tubes can operate at serviceable temperatures to 1500C (3450F), and they can be had in 4", 6", 8", 11" and 12.5" diameters, up to 24" long. .

Are you sure? On that link I could see lengths like that, but the diameters seemed to be in mm, not inches.

Maybe they have others I haven't found yet.

Burra Maluca wrote:

Kevin Prata wrote:

These tubes can operate at serviceable temperatures to 1500C (3450F), and they can be had in 4", 6", 8", 11" and 12.5" diameters, up to 24" long. .

Are you sure? On that link I could see lengths like that, but the diameters seemed to be in mm, not inches.

Maybe they have others I haven't found yet.

Darnit! You are right. I misread the spec sheet. Uggghhhhh. Still, assuming it WAS actually 8 inches, rather than 8mm, it seems like it would be a great material!

Thank you though, for your quick response.

Regards

Kevin Prata wrote:t. I misread the spec sheet. Uggghhhhh. Still, assuming it WAS actually 8 inches, rather than 8mm, it seems like it would be a great material!

Regards

Yeah - I got quite excited there for a minute. But keep looking, maybe there's something absolutely perfect for the job out there that we haven't stumbled on yet.

Hi -

Thank you for the links. I had seen that stuff before, but couldn't find anywhere to buy it at retail online.

However, I found something else very similar to that and to the Vermiculite board used in the Dragon Rocket Stove riser. This stuff is called Kaowool and it seems to be available for less than 1/2 the cost of the Vermiculite board, seems to serve identical function, durable up to 2100F.

http://controlscentral.com/eCatalog/tabid/63/ProductID/504451/SearchID/5/SearchValue/Keywords/SearchPartNumber/10251/SearchManufacturer/Manufacturer/ViewType/2/Default.aspx

It looks like inswool blanket / kaowool blanket, either one with a coat of satanite or ITC-100, might do the trick! Cheap too!