Modify OWB for better efficiency?

[Hosted]

I was wondering if anyone on here has modified their OWB to make them more efficient or at least burn off some of the smoke? I have found the website below where this guy has modified his some but it seems like he now has a shorter burn time because of lost space and it sounds like it needs lots of adjusting. Anyways, I was wondering if anyone has made some modifications to make them more efficient. I would like to get one, but I have two neighbors that I'm afraid of smoking out. Would go with a gasifier, but can't justify spending the extra $4000 or so it would take to have one. Thanks in advance.


http://www.woodheat.org/technology/outbobpen2.htm

 

[Slick]

I would love to but voiding the warranty is kind of scary...I've thought about several thing similar to that..one used steel plates over head similar to his ceramic alumina plates but with square tube legs coming down to the floor to avoid needing all the firebrick which eats up firebox space.
Anyone seen a recent update from that guy?

 

[trialanderror]

i modified an indoor pressurized boiler to be used as an outdoor nonpressurized boiler....

put a water jacket all around it, insulated it like a mofo, and added a 2nd draft fan. water pops and cracks it heats so hard/fast. Best move i've made. It's equivlant to heatmors 3000sq ft model. ~90 gallons in the water jacket heating almost 700gallons in two zones.

it's a steel king 4300b rated for 485000 btu/hr.


oh, added a digital control like the ones that CB's come with. also welded on a million fittings with plugs just in case i need to add something later

it doesn't really smoke. it's got firebrick on the bottom with a ash grate down in the center, and i open the door, and it's seriously a cube of coals, 28" deep by 24" wide by 20" high of just red blazin heat....no smoke. unless i add something.... me and dad are working on a water cooled door, as that's the only thing where heat loss is at the moment

 

[igloo]

OWB mods

I think the idea is good, I have started to modifiy mine by adding additional water storage, 1000 to 2000 gallons. I dug a hole next to my house and poured a slab to put the storage in. I figure I will have no heat loss from the storage tanks as they will directly heat my basement. I also have plans to put fire brick inside my burner.

igloo.

 

[ghitch75]

i put a 6" flue down in mine 12" from the bottom of the firebox( 8" factory pipe out the top) and it is reduced down to 4" at the top.....went from a 1/3 of a cord lasting 7 days in under 20f weather to 13 to 14 days on the same amount of wood....it takes half the time to go from 160f to 180f...i didn't care about the warranty...got it in a trade.....guy i got it from had a friend fill it while he was out of town and he left the ash pan door open and it boiled all the water out of it and busted the water jacket in 8 places...so after a lot of weldin' i modded it...

 

[Hosted]

Ghitch, did you just put a rducer on the top of the 6" stack, or did you acually run some 4" down the stack? Also, is the 6" stack in the middle of the firebox or in the back? It seems like it would get hit with logs if it was in the center of the firebox? Sorry for the stupid questions, it just amazes me how something so simple can help out so much.

 

[barkeatr]

im in the process of building a greenhouse around my OWB, I purchased a magic heat heat exchanger to go in the chimney. how will this improve efficience? by using waste exhaust heat i hope to raise the temperature that the OWB resides in by a lot...reducing heat loss. its almost a gogeneration kind of set up.

My worry is that i will burn out the magic heat with the occasional chimney burn out....but If im quick enough i can get the door closed on the OWB to stop the fire....

T

 

[ghitch75]

Ghitch, did you just put a rducer on the top of the 6" stack, or did you acually run some 4" down the stack? Also, is the 6" stack in the middle of the firebox or in the back? It seems like it would get hit with logs if it was in the center of the firebox? Sorry for the stupid questions, it just amazes me how something so simple can help out so much.

it's in the back in the middle about 4" off the back wall.....the 6" runs down 12" form the bottom of the firebox...the 6"x4" reducer in on top...here is a couple pic's....hard to see inside with the smoke....

 

[timerak]

Look at the Aqua-therm site. The Eco-one retrofit is a fairly simple mod that could be done to most QWBs.

http://www.aqua-therm.com/

 

[Paso One]

I also have plans to put fire brick inside my burner.

igloo.

Does the fire brick actually retain that much extra heat???

 

[igloo]

I think the benifit from the fire brick is to create a more efficient combustion chamber to extract more of the btu from the wood instead of sending it up the flue as smoke. The "cold" combustion chamber that you have when you use the water jacket as a fire pot doesn't promote complete combustion of all the fuel available from your wood. The water is the material used to retain the heat, by adding more water you can store more heat provided you have enough insulation to contain it. By adding the fire brick you give your wood a more efficient enviroment to burn in, then you modify your heat exchanger, or smoke path to transfer the extra btu's that you got from your wood into your water. I hope that helps explain, cause thats pretty much the way I figure it all works.

Igloo.

 

[paladin]

I was wondering after talking to a few owb owners and they seem to feel that when it is windy out that the burner is less efficient. Could putting up a small building around your owb help the efficiency? Maybe even insulating it a bit. I currenty have an inside burner but have been studying about the owb's to maybe have one someday.

 

[Paso One]

Hi Paladin
My OWB is located inside an old semi trailor Van.
Allows me to store wood and fill the boiler in sheltered area.
I'm also working on a WMO boiler piped into the primary loop.
This is also housed in the trailer.

A shed is a great idea for any installation IMHO

 

[Mikeweems]

trialanderror do you have any pics?
I have a inside pressurized wood boiler I'm converting to a OWB and need some ideas. The description of your boiler sounds exactly like mine.
This is my first try at this so any help is a big + for me

mike

 

[igloo]

I think putting your OWB inside some sort of wind break or building is not a bad idea. Even though they are insulated they still lose heat, and when it's windy it loses it faster, just like when you blow on something to cool it down faster. Plus it's nice and warm when you reload on a cold morning. I am adding insulation to mine in certain areas in addition to the wind breaks I have erected.

Igloo.