Barrel Stove Heating Question

Option A is better. Snaking the pipe around the building will only cause troubles.

This is a more common application.

Does that one not have a catalytic converter in the connecting pipe?

Check your codes before considering the snakey pipe in B, which is likely to screw up the draft and you will get a smokey blowback. Also the bends are a likely place for creosote to condense, so after a little use, risking a fire in your pipe instead of the firebox.

Stove pipes are thinner metal. The heat off a pipe can be extreme. Many people have had house fires because they hung or propped things on the stovepipe (including firewood set to dry!). It is not a safe radiating heat source. Best config for stovepipe is into a proper chimney. Secondly the thin metal doesn't have much radiating capacity once the fire is out. It doesn't have the mass to store heat effectively so the whole system will be cold quicker.

In setup A, your extra drum is probably heavier gauge metal than the pipe, as well as containing an open space that will continue to collect warm air from the embers of the fire, and radiate heat back to the room for awhile after the fire has gone out.

I couldn't say for sure if it will generate "more heat" than setup B, but it will generate more moderate, even heat over time, where the heat from B - especially when the creosote catches fire - may be enough to torch the place ...

I'd go with A, but cut some 2 1/2 diameter holes in the sides of the top barrel and weld some exhaust pipes through it to act as heat tubes. Maybe even put a fan on one side and circulate some air throughout the room. Let the pipes stick out of one side and mount the fan on them.

Get the idea?

You want to keep bends to a minimum. I would run straight pipe or like in #1, but with a much shorter horizontal run. Make sure your roof vent is a minimum of 4' from any roof surface. To get the most heat in the building, get one of these:

http://www.northerntool.com/shop/tools/product_200331512_200331512

Ok. Thank you all again. A. it is.

I had a setup like yours for about 10 years. altough Mine was vented straight up thru the roof, a run of about 15 feet. I used the common "oil" drums from the scrap yard. I also installed a centrfagal fan (small) into the bung hole on the bottom drum this allowed a nice draft to get the wood burnning hotter. of course the draw back is You burn more wood.. I had always thought about burning coal but its hard to find nowadays. Anyway the wood was cheap, cost Me nothing!

oilcan13

Do not attempt to burn coal in an oil drum as a principal fuel. The thin metal won't respond well to the higher temp. However, a few chunks added to an established wood fire may be a benifit.

I say you MUST go with the double drums because you will have so much creosote buildup in the flu that you will have to take it apart to clean it out or risk it catching fire and becoming very red! And the snaking flu pipe would be hard to take apart. I would even be tempted to go with an insulated flu pipe which is a pipe inside a pipe. That way it will keep the flu hot enough to prevent the creosote from building up. If you have warm days and you have a low fire creosote will build up and then you get a cold spell and crank open the draft then you begin to hear this roaring noise. You run outside to see flames leaping out the chimney 6 or 8 feet tall and blowing chunks of flaming creosote that fall back onto your roof. If you have a metal roof it may not be so bad but if you have a roof that will burn then you grab the hose and start spraying. Chimney fires can get so hot it will turn the inside of a good lined chimney to glass and possibly crack it. If it's an old chimney with loose mortar and bricks well then you got a problem. I lived in an old house that had tarry streams of creosote running down the chimney inside the attic. Very scary. I cleaned that chimney once a month. It was black and shiny inside.

They use to sell the kits for 1 or 2 barrel stoves.on the 2 barrel stove the lay the barrels LENGTH ways Not standing up like you show.The 2 barrel stove put out more BTUs. you take the 1st barrel cut out the door and install the cast iron door in the front, then in the back cut your hole for your smoke pipe fitting, now take the 2nd barrel and cut a hole in the back on the Bottom, [this will fit over the 1st barrel. ] and cut a hole in the Top Front for the smoke to go out.Put in a damper in your smoke pipe and enjoy. I have made and used these for a long time.And the DON'T burn out. like some people say,I have had the same barrel for over 5 years and its still just like new.Leave about 2 inches of ash in the bottom.Ok here is a link for a Double barrel stove kit,It's well worth the money.The parts are all cast iron and they dont bend from the heat.and they are only 34.00. copy the link

http://www.northlineexpress.com/itemdesc.asp?ic=5sv-BKAD500&source=froogle&kw=5sv-BKAD500

Looks like they wont let you copy and paste here.

Try to keep stuff atleast about 2 feet away form the stove.

what I do is on the bottom barrel you will see a 2 inch plug. I take that out and put in a plumbers fittings. a 2x1 bushing, then I have a 1 x 3/4 so I can adjust the air better.

They work very good....Good luck.... yes I still use one in my work shop

Forgot to mention, most use 6 inch smoke pipe.

Looks like they wont let you copy and paste here.

1. Put what you want to copy near the middle of the screen.

2. Do a screen shot that saves it in memory as a grahic image. My gateway laptop uses Fn+insert key sequence, check your system for "Print screen".

3. Open a graphics program. I use either Irfanview or MS paint.

4. Paste the screenshot.

5. Usng the selection tool, left click and drag to select the area of interest.

6. Click the copy button on the toolbar or select "copy" from the edit menu.

7. Paste the item where you want it.

Or, drag your cursor across whatever it is that you want to copy while holding down the left mouse button to highlight it, then hit control "c". Return to the CR4 screen and hit control "v" to copy it onto the page.

Question: Which will generate more heat inside the building?

Answer: The one that will be able to consume more kg of wood per hour.

A well constructed barrel stove, can burn wood to a maximum rate around 12-18 kg/h.

Regarding the available space inside the barrel for wood: (A) equals (B).

Regarding the available air to be supplied to the fire: (A) can give a little more air than (B). But as the fuel rate increases, this difference (betwwen B and A) decreases, and at maximum fuel rate (more than 15 kg/h), it becomes almost zero.

If your question was "Which is more efficient?", then there would be a different answer. Propably (B).

One important part I left out.....This is set up on a Propane burner not wood or coal.

Does that make a difference?

Not a lot.

You still want to run a straight or near straight run of exhaust pipe, the reason being, is that with multiple bends, every time a breeze blows outside, it's going to blow the, (cooled), exhaust gasses back into your work/living space. The problem with using your exhaust pipe as a heat exchanger to heat the space, is that heat is required to carry the exhaust up and out.

That said, since you are using propane as your heat source, you can drop the size of your exhaust pipe down to 6" or maybe even 4" pipe. This will allow you to retain more heat within the drums. That's assuming you're not going to be using it as a barbecue and cooking on it.

I should also point out, that since you're using propane as your fuel source, they sell propane fired furnaces that would probably be a lot more efficient than burning propane in drums.

I see that A. is still the better. Its what I have now. The snakey version was a suggestion by a friend. He said slowing the exhaust would make more heat inside.

i built one of these (B) years ago but had a heat channel that kept the upper drum very hot. There was a secondary burn in the upper barrel from un burnt CO. We actually got more heat from the upper , when the exaust flue was properly adjusted, than the lower barrel.

Ron

Ron,

What would your heat channel look like?

nm

Actually it was like what Doorman posted above except for welded in panels that contained the heat from the lower drum to the top drum. Installed a view port in the upper drum and after the drum got hot enough you would see the flame ignite and dance around the inside. Un burnt CO. we then installed a small valve to the outside(air feed) of the upper drum and when properly adjusted (air inlet,lower flu, upper flu)

the upper drum would get very hot. I did not measure the temp but the upper drum would drive us out of the building, to the point that i was worried about thermal expansion and stresses on the upper drum.

Ron

Something like this.

Ron

Yep, it will, but at the same time it will cool the exhaust gas, making it heavier and dumping back into your space. Unfortunately, some degree of heat loss through the roof is necessary. No snakey.

I believe a lot of it depends on the fuel. A dirty fuel (coal,wood) left deposits. We did not try gas fuel.

Ron

I've got a pretty efficient forced air heater that runs on propane. The exhaust gas is not real hot. I really don't know what the specifics are for burning propane in a drum setup. I do know that running vent/chimney pipe vertical or near vertical is standard.

There are some pointers here that would also apply to this situation.

http://www.ultimategarageheater.com/choosing-a-garage-heater/propane-garage-heater.php

Both methods would work. However the problem is not in getting heat out of the unit, but rather in cleaning up the mess from the smoke condensing in the pipes.

Long pipes mean that you need more height to create a draw. So the long pipe method may actually waste more heat. OTOH, burning wood is carbon neutral, so if you have lots of wood, go for it.

Bill

From Northlineexpress.com, for $114.00 if you want to get fancy. I'd say that price doesn't include the stove.

Number two is the best bet, in Norway most of the wood burning stoves have this arangement, the amount of heat radiating from these S bends is enormous, and any room it is in will quickly heat up!

Xanasax

I could be wrong, but in the US, if a fire was to occur using that arrangement, any insurance that a person had on the dwelling would probably be null and void.

Fishing camp..... not a house .

The generalization of a likely possible structure fire is applicable equally to a house or a fishing camp. While you fish camp may not be insured, an unscheduled undesirable thermal event can disrupt your plans.

Point taken on the fire.

All care will be used including metal sheeting on walls over fire rated sheet rock and of course steel roofing. The floor is 4x4 cement board with brick over that.

smoke and co2 detectors will be in place also.

"...and any room it is in will quickly heat up!"

See kramarat's comment about that house fire!

If you are sure the fire is the same on both, measure the exhaust temp, the cooler is putting more heat in the building. -- JHF

Well, you've got me thinking now. I don't know if you care about efficiency or the amount of propane you use. Originally, I thought you were burning wood. Now I'm wondering if you shouldn't completely get rid of the drums and go with something like these highly efficient and reasonably priced units. Vent free too!

The 30,000 btu units are around $200 US.

http://www.heater-store.com/propane_space_heaters_115_ctg.htm

I looked at these and wondered if the barrel arrangement would put out more heat or if these heaters would?

Any good guesses?

Since these are designed to be vent free, they operate at 100% efficiency. All heat stays in the space. I'd be worried about attempting to run your barrel heater unvented. I don't know which will give you more heat, but I know that these will give you more heat for the dollar. Maybe give the people in the link a call and describe your situation, see what they say.

Ok, take the lower barrel and restrict the O intake,this puts out more CO. Blow some steam in the upper and put the upper under pressure. This makes a hydrocarbon gas. Run the gas (under pressure) thru a Fisher-Tropse (sp) filter (steel wool compacted) and you have bio diesel.

Ron

Or creosote.

This is again simple:

Heat in the inside the room or (you write here building) is influenced more only by the convection type of heat transfer from heated surface areas in contact with the air. Definitely, say at temperature T where you have to maintain the heated solution or what ever,is attained (at both set up, A & B),

First in mind; convection heat transfer is directly proportional to the surface area, the bigger the surface area of the bigger the heat transfer. Then it comes that the exhaust stack with alot of bends (B) from your illustration will transfer more heat in the air of the building rather than A.

By the way, take time to reflect coils from evaporator and condenser (heat exchangers) why are they designed like that.