making my own owb in the future had an idea and want some input

Hey guys right now I have an empire deluxe 2. I like it but sometimes it pushes a lot of smoke out even with drier wood. (I just bought the house last year and am finally starting to get ahead with the firewood situation) I burn pine ash oak birch anything that I find that is dry as I can get it. Next year will be better yet. But my question to you is this, when I build my own owb, I would like to run a fan, and to make it more efficient and less smoke I want to re circulate a portion of the exhaust, to reburn some of the valuable gases that go out and pollute. Any ideas on this? I will try to upload a drawing later. It will function some what like a gassifier but without all the extra work and welding. Any ideas or any of you that have tried something like this that have input would be greatly appreciated.

 

Here's a picture of my rough plans

 

Thank you! I only have one neighbor a eighth mile away on our dead end road but I still don't want all the smoke. It just makes more sense if this will work why wouldn't I try to configure it right?

 

never seen a re-burner of sorts like you are showing except for in one of them charcoal making contraptions. you still need to get the recirculated gasses hot enough to combust. incoroporate substantial firebrick to isolate the fire from the cool sides of the firebox. thats the idea of the secondary chamber in a gasser, along with injecting more air. that ratio is important BTW. manufacturers kinda know what they are doing and they generally dont make extra work and welding for themselves if there wasnt a reason for it.
i like fireboxes with a negative pressure. this keeps smoke from rolling out when reloading.

have you tried adding firebrick to your delux?
what is the rational behind building your own?

 

As far as I know all owbs are hydronic, with a water pump in the house or out by the owb. The forced air is just the fan that kicks on to blow air into the Firebox when the water gets down to the set temperature causing the fire to start abd bring it up to temperature then it shuts the fan of water circulates continuously, done owbs are natural draft just controlled electronically.

 

If it blows the re circulated smoke directly into the fire and coals wouldn't that be hot enough? I don't think I'd be able to re circulate more than 25percent of the smoke anyways but is worth a try.
No I haven't tried putting any fire brick in yet mainly because there's no good place to put it and be able to add wood without it falling constantly
I'd like to make my own because I can get the steel for cheap through work and I'd like to have one to replace the one I have when it's seen its last days I've been welding for a few years now but am more than confident on my welding abilities just not my design and electrical abilities yet

 

if it was hot enough, wouldnt it have ignited in the first place? IIRC, you need over 450*F. the firebox sides (if there is water opposing it) will be about half that required temperature. anything is worth a try. especially if your materials are cheap and you got the time. make air settings adjustable so you can play with it.
electric can be as easy as an aquastat turning the fan on and off when it hits hi and low setpoints. the controls for mine are as follows: main switch. button to start fan. stack temp probe takes over after 30 minutes and keeps the fan on until that temp falls below set point (this means that the fire has burned out). and an overtemp that shuts the fan off if the boiler water reaches 210*. this is burning to storage so your controls would come on and off at say 170-190.
have you pressure tested your welds?
not trying to be a debbie downer, but there is a lot to think about if you want to do it right. otherwise it turns into colossal waste of time. fun to experiment tho.

 

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I suppose I could make a secondary burn box with the fire brick problem is capturing some of that heat with water is all a catch 22 being as the water cools it down. My welds aren't a problem many are ultra sounded, leak tested with air and water, wet and dry mag particle tested and actually one of the projects I'm included in at work require 4different tests in various stages (they are outrigger legs for cement pump trucks)

 

Wood coals can be well over 2000degrees I think the having the chance being blown back over the coals and through flames the smoke and exhaust would do a better job being burnt up. I know with an owb i will never get zero smoke but even if I reduce it by 20percent it's a step in the right direction this is another big reason it's like to build my own. I have plenty of time for research I probably won't start until next summer

 

very good on the welding. i hear many a guy with a box store MIG claim "my welds look great! they must hold pressure."
some designs i researched when i considered building my own: varmebaronen, P&M, woodgun, garn, switzer.

 

I will have to look into a few more I have a few I've looked at from Taylor(which I don't care for at all) to the empire to another that my buddy has

 

You'll probably not want to recirc the exhaust with power the way you are showing it. It will be oxygen deprived, mostly non combustibles, and moving it quickly across the coals will do more to blow things out most likely. What are your goals regarding firebox size and burn time? Do you have a buffer tank for thermal storage?

 

Even with much 25percent (at the very most) probably more like 10percent being recycled through do you think it'd blow itself out? I'm going to most likely go with a round fire box(less welding less stress less places for leaks) I'm hoping to bee able to fire up once per day on average. And no I have no thermal storage so far but will be doing that before I switch out stoves. I like the idea of the fan running longer and less often rather than on and off all the time having longer burn times helps with the smoke as well I have found

 

Thing is with the fire brick,will I lose heat with that lining some of my sides?being as the sides transfer heat to the water having fire brick there will that act as insulation?

 

i have seen angle iron welded in place to make slots to slide standard brick down into.
insulation slows the heat transfer, not stops. once hot, the dense bricks will continue to give off the heat that they take in, mostly. they will also continue to give off heat after your fire goes out. this allows you to start messing around with batch burning. better tho is to have your flu gases go through a series of tubes to get the heat out. all the models i listed in #11 have an uninsulated firebox, insulated secondary chamber, and heat exchanger tubes. varm, P&M, and WG are downdraft. garn and switz are horizontal.
spend some time on youtube to gather ideas. what is your heat delivery?

 

Heat delivery is just a radiator in my plenum in the house along with heading my dhw

 

ok. seams like you are already, but you probably want to stay away from a design that incorporates the firebox inside of the water storage. you need hot temps to your radiator and with incorporated storage (garn, switz) you have to heat the whole thing up before you have water hot enough.