Briefly, I have built one stove, a five gallon pocket rocket. Saw the elephant, smelled the smoke, diving in prototyping.
I picked up a new steel 30gallon drum yesterday. Standard size? Inside dimensions 18 inch diameter by 27 inches tall, or 46cm diameter by 69 cm tall, reader's choice.
I have some six inch single wall stove pipe. The only four inch I can get local is for pellet stoves, rated to 570dF only.
I have access to both clay split size firebrick, and pumice full size bricks.
My existing woodstove is a EPA cert non cat, weighs about 450 pounds all up. Got some years on it, parts are getting hard to find. Its on the second floor, wood framing below. The good news is it is on a Type II hearth, R=2.72.
I don't want to build a multi ton mass into the second floor of a house we are trying to sell. My wife and I are hoping to get the last of the kids out in maybe two more years and move into a smaller cottage type dwelling.
So I got this 30gallon barrel.
To maximize radiant output, I think I have two options. If I go with the 6" pipe throughout I'll need to build a brick/cob fire tunnel and feed tube in a metal box - with legs on it to get it off the floor, and then set the drum over the heat riser just like the mass heaters. Good experience and the 6" output will mate right up to my existing chimney if I can get the rocket to behave.
Second option would be to go with smaller diameter pipe to fit the burn tunnel and the heatriser inside the drum. Then I can put legs straight on the drum, save a bunch of weight but give up some output capacity via smaller diameter pipe.
Am I carrying a candle into the dark here? Does anyone have any BTU numbers so I can compare a 4-5-6 inch rocket stove with no mass heater to an EPA cert box type woodstove? I get the rocket uses too little wood to actually take the EPA test, but how much heat can the fool thing put out running as designed?
I'll see directly if I can drop links to photobucket in here, I may need 10 posts firsts or something...
Ambient air was +/- 10 degrees of zero farenheit, warm enough to play in the yard, cold enough to get really good draw.
Here is a really long handheld exposure of the first burn. If you kinda squint you can see three realyl hot buckets, three really hot stacks and three flames , one each coming out the top of each stack - with those same little four sticks pictured above. The yellow/white stripe was me pointing the camera at my neighbor's back yard light hoping to get the shutter to close...
And finally, the second burn, stack out put. Not as impressive as the first burn, but still impressive to me.
If you just want a heater check out ZeroFossilFuel's 4" design. ZeroFossilFuel It can be scaled up for a 30gal barrel. It has a low final output temp suitable for a regular pipe flue. I was very impressed with the simplicity and relative low cost to build. Moderate fabrication skills and equipment are a general prerequisite.
He gives detailed plans and analysis of operation (pdf download) and some youtube vids of the project. You can search the forum here as he has posted some about this design.
"Necessity is the mother of invention" That's why I'm a Jack of all trades, Master of some and have learned that Knowledge is power, but information isn't necessarily knowledge.
You can also look at Peterberg stacked barrels one. "near pish easy to make"
Horizontal batch rocket made out of insulating firebricks don't weight much. You can do most of the core dry stacked. And bell wise they can cope with 60sqf 6M² of internal surface area (isa) for a six incher. You can find some home heating fuel or tractor fuel tanks which instead of round can be square/rectangular, and a 1000l, common in europe are usualy quite near the required isa. Square type can have bricks, concrete blocks, cobble stones, pavers or whatnot, dry stacked on top and on the sides for a little mass. I advise to butt the back of the tank against a massonry wall. And for less weight also for quick heat, leave the front bare.