Have fins been added to top barrels before?

Have things like this been tried before?
Adding heat dissipators or heat transfer fins to the side of the barrel.
Stacked doughnut rings or vertical plates etc.

Here are two sketches of what I mean. They could be horizontal or vertical or any combination in between.

Holes could be drilled in the fins to add edge surfaces for heat transfer to room.

I saw MANY pictures of RH but they all had a smooth type drum or barrel. I think it would make sense to add
more metal to dissipate the heat.
What are your thoughts and experiences?

Danford1

Do a Google for "Zero's Rocket" - he's attached vertical fins.

LJ

Nice! Thanks. I read where before he added the fins he could get his top tank temp to 700 degrees, after the fins it was only 500 degrees. That is 200 degrees more heat radiated to the room.
That is what I was hoping for, more heat from smaller tanks. Plus the exhaust temp was reduced which verified more heat was going into the room.

I see from his design that he didn't make the burn chamber opening to the riser, smaller. I read where that portion should be a smaller dimension.
Also he didn't have any secondary air in the riser for the vortex.
From further reading, shouldn't his outside air intake be a bigger diameter? I like the way he incorporated that. To me it just seems like it should be At Least 4" not 3"...

I like most of his design and integration. My mind is already spinning thinking how to add a secondary air chamber inside the combustion chamber. That reduces the size of the opening into the riser and feeds heated secondary air in for the vortex. Some easier to use clean outs, pellet feeder system, more fins on tank, top flat plate on tank and on and on ... I'll do a Bunch more reading then combine design ideas and come up with something...

Danford1

Dan Stolarczyk wrote: Nice! Thanks. I read where before he added the fins he could get his top tank temp to 700 degrees, after the fins it was only 500 degrees. That is 200 degrees more heat radiated to the room.
That is what I was hoping for, more heat from smaller tanks. Plus the exhaust temp was reduced which verified more heat was going into the room.

During my collecting of information on Rocket Heaters I came across this design - and to be honest I thought that those fins were probably unnecessary. But - having now actually built something similar, I can more fully appreciate the need for them. I've gone for a large firebox design, with a 5" flue and 4" riser - the idea being to get something of a venturi effect as the gases accelerate up the riser - which they certainly appear to be doing, as it roars like a good 'un. But - the exhaust is running far too hot, so it's either extend that significantly, or fit fins - and right now fins are looking like the most acceptable option.
'best
LJ

One of these days I'd like to find an extra lid for my barrel to experiment with... I know of at least one type of heater that uses little pins in the convection air stream as part of the heat exchanger...I keep wondering how much more heat the top of the barrel could radiate with a whole bunch of long (say 3") nails welded to it... Would give it a ton more surface area to radiate off...well, as long as you don't mind it looking like a porcupine lol. Even a few big ones (like pieces of rebar) would help I would think. My system doesn't have a mass (just a single bell), so I'm looking to radiate as much as possible...in a traditional system you' don't want to strip off so much there's not enough to heat the mass...

Exactly. In a mass heater you want the exhaust to have heat for the mass. With just a heater, we want as much heat as possible drawn off and radiated to the room.
I also thought of pipes say 1" in diameter running thru the bell above the riser. The pipes would be hollow and allow air to be drawn in and through them for heating the room. Perhaps even a low speed fan blowing thru the pipes.

Once I find time and scrap, I'll start building and experimenting. I just want more of a plan before I build. My spare time is very limited. Too many other projects going at once...
Danford1

Here's what the (running) mockup of my system looked like in the driveway...



And the final install in the garage:



The system runs like a champ, but there's still a tiny bit of room for improvement...the final exhaust pipe is still probably a little hotter than it needs to be. I can put my hand on it and not get burned, but I don't want to keep it there for more than an instant. Never seem to get any smoke at all...there's a little steam as the system heats up, but that's it. The weird looking horizontal pipe is going to have a blower hooked up to it shortly to make a "heat scavenger" for lack of a better term. The water heater still has the original flue pipe in it (it was gas fired) and the swirly heat exchanger inside. Originally hot flue gas heater the water, but I'm going to make it run in reverse--force room air down the heat exchanger so the hot bell will heat the air...then it will exit the bottom of the bell at the old burner location and go out into the room... I'm hoping to get my EGT down...on the (small) chance that I'm able to scavenge enough heat to cause a draft stall, I can put a speed control on the blower. Given that it probably won't get over freezing until next year, it's probably not going to be an issue no matter how much I cool the bell off...
Makes for kind of a funny looking machine though. It's a nice aesthetic if you like your place to look like you have part of a steam locomotive in it lol. It's in the garage, so whatever. I actually kind of like the industrial look out there.