What is the most efficient stove on the market today?

[_CY_]

that's exactly the design I've been contemplating. was thinking of a design to duct outside air into floor ash dump port. then build a slider to control main outside feeder air when unit gets up to temps and is ready to switch to secondary burn.

very seldom load up all 12cu ft full of wood. but it sure is handy being able to load up to a 2ft x 2ft log inside. needless to say.. don't do that very often, log gets too heavy to handle.

was looking for help in designing a secondary burn system for my JUCA.... that's one of the main reason for starting to visit Hearth.com. loads of knowledgeable folks on this site!

Thats all good, unless you have to have that 12 sf loaded up with wood? then its apples to apples.
If you could put a channel or even plate the bottom with support between the steel plate & the brick floor, then connect a vertical channel in the back like my PE has., then make a similar S.S. baffle that you could mount under the heat exchanger tubes and it sits over the rear vertical channel. You might get some great heat & secondary burn. And not lose your heat from the exchangers and the outgoing gases & heat would still heat them up. Not to mention being over the secondary baffle. Then just an air intake on the lower front. Might work.

 

[_CY_]

here's JUCA in action taken a few minutes ago... temp at exit duct is 180f, blower at high rate of flow. temp above door is 120f, temp in front of unit is 103f

chimney shows no visible smoke coming out = hot/clean burn

 

[Todd]

Where is the exhaust on that Juca beast? Are you saying it runs through all those heat exchangers like a masonry heater?

I tweaked my heatform masonry fireplace by adding a ceramic baffle and outside air through the ash dump and noticed a big difference in heat output. I was also thinking of secondary burn tubes and some kind of air wash for the glass but really don't burn it enough to make it worth the investment. I think the biggest improvemnt you could do is outside air since it seems you already have a clean efficient burn.

 

[Hogwildz]

You might want to PM Corie, he is a engineering grad and now works at Englander.
If he is not too busy designing the next greatest thing, I am sure he could help with design.
Me personally, I would almost copy what I have in my Summit now, cept on a larger scale.
Of course the baffle being that wide, would need some kind of ribs or webbing inside to help keep the middle from sagging after it gets hot.

Just curious, have your cleaned the chimney since burning that? And what if any is the accumulation like?

 

[_CY_]

all makeup air is already coming from outside via ash dump in brick floor. exhaust goes directly upwards into existing masonry chimney. heat exchange comes from HUGE contact area. fan driven air goes across making heat exchange.

currently updraft is controlled by carefully adjusting top damper to control smoke hang time/levels.
damper is adjusted to keep smoke level just above the door opening. results is carefully tracked by CO meters, one Fluke hand held and a stationary CO monitor.

JUCA is one big hollow heat exchanger! design has been in production for 20+ years, hence lack of secondary burn. but look at how long Russian fireplace design has been in use.

design is fairly complex to fab. JUCA basically has posted plans on it's web site for all to see.
not a metal fab person, but sure seems custom fab to order for each order would be labor intensive.

always checking for creosote buildup... JUCA burns so hot and clean, after 3 season barely anything came down when I cleaned chimney last year.

thanks for the tips on constructing a secondary burn... was planning on using 1/4in plate to make baffle.... needs to be in sections so I can experiment with how much baffling is needed.

Where is the exhaust on that Juca beast? Are you saying it runs through all those heat exchangers like a masonry heater?

I tweaked my heatform masonry fireplace by adding a ceramic baffle and outside air through the ash dump and noticed a big difference in heat output. I was also thinking of secondary burn tubes and some kind of air wash for the glass but really don't burn it enough to make it worth the investment. I think the biggest improvemnt you could do is outside air since it seems you already have a clean efficient burn.

 

[Todd]

It sounds like the JUCA gets a clean burn from alot of combustion air. I didn't see any EPA numbers from their site so they must be one of those 35:1 EPA exempt stoves. You probably could benefit from a secondary burn system and more air control, but would be really tricky getting it to work right. Keep us posted how it goes, someday I'd like to do something similar with my fireplace.

 

[Hogwildz]

all makeup air is already coming from outside via ash dump in brick floor. exhaust goes directly upwards into existing masonry chimney. heat exchange comes from HUGE contact area. fan driven air goes across making heat exchange.

currently updraft is controlled by carefully adjusting top damper to control smoke hang time/levels.
damper is adjusted to keep smoke level just above the door opening. results is carefully tracked by CO meters, one Fluke hand held and a stationary CO monitor.

JUCA is one big hollow heat exchanger! design has been in production for 20+ years, hence lack of secondary burn. but look at how long Russian fireplace design has been in use.

design is fairly complex to fab. JUCA basically has posted plans on it's web site for all to see.
not a metal fab person, but sure seems custom fab to order for each order would be labor intensive.

always checking for creosote buildup... JUCA burns so hot and clean, after 3 season barely anything came down when I cleaned chimney last year.

thanks for the tips on constructing a secondary burn... was planning on using 1/4in plate to make baffle.... needs to be in sections so I can experiment with how much baffling is needed.

Where is the exhaust on that Juca beast? Are you saying it runs through all those heat exchangers like a masonry heater?

I tweaked my heatform masonry fireplace by adding a ceramic baffle and outside air through the ash dump and noticed a big difference in heat output. I was also thinking of secondary burn tubes and some kind of air wash for the glass but really don't burn it enough to make it worth the investment. I think the biggest improvemnt you could do is outside air since it seems you already have a clean efficient burn.

Sounds like a good plan. Once you get a design that works and your satisfied with, you may want to consider s.s. for the final baffle.

 

[tlhfirelion]

I think a properly built masonry heater can probably meet or beat many stoves

On the style of a "Russian Fireplace", or something else???

Yes same type of thing. They are great stoves, but they cost a ton and weigh even more. lol I think since I'm in the southern midwest, it may be overkill for my location, especially since I'm planning on building an ICF home. A good wood buring stove would do fine for the 4 months I would need it.

 

[Rob From Wisconsin]

No wood stove is going to return 80% or more of the heat into the house on a constant basis....given cordwood, variable burns and normal conditions and testing. Most of the figures you see are either guesswork, wishful thinking, or omissions. Unless...and until we get an actual standard for cordwood and real world testing, it is always better to figure low and work with 65-70% efficiency with the best woodstoves, and less with most inserts due to heat loss.

I think a properly built masonry heater can probably meet or beat many stoves.

I believe totally what Craig is saying....
I got my hands on a book that gave a broad overview of stoves & the latest technology at or around 1980.
You should have seen some of the scary chop-shop contraptions that were claiming 90% efficiencies

 

[arcticcatmatt]

just google "Russian fireplace" ... WOW....
the designer below claims to light a fire once a week. takes all day to heat, but radiates heat for 3 days.

"Masonry stoves are designed to burn a hot fire, with the air supply and chimney damper wide open. This results in a clean burn, with little visible smoke."

this is identical to how my JUCA operates...

http://www.grannysstore.com/Do-It-Yourself/masonry_stoves.htm

http://www.grannysstore.com/Do-It-Yourself/diyimages/masonrystove.d.jpg

10-4 on that. My russian fireplace rules. Its a different design that what you have pictured above but same principle. It has been mostly 25-35 here for a month (a few days were warmer but not too many). I have heated my house at about 70 degrees all month on a little less than a pick up truck bed full of firewood. Maybe 2 face cord? Mine even semi heats my garage. its probably 60 out there.

I do 1 fire every 12 hours. The amount of wood per fire fits in a 5 gallon bucket. My firebox is only maybe 12"wx12"h. An arm full of wood. I split it VERY fine so I get a super hot fire that is OUT in 1 hour. Then I almost close the draft. Hours later the brick keeps getting hotter and hotter and hotter. 3 hrs after the fire.. almost can't touch the brick. 12 hrs after the fire, the brick is probably still 120 ish. I will get a temp gun soon and do some "studies" on it.

If anyone is building a NEW house or NEW addition, a masonry stove should strongly be considered. My first post here a month ago was a thread about my stove.. check it out for more talk on masonry/Russian fireplaces.

If anyone is local to Berkshire NY.. I will show it operating to you if you would like.

My apologies to the thread starter.. I know he said "besides Russian fireplaces"

 

[bokehman]

That much 10-15% wow

8' of 6" stovepipe at 400ºF radiates 11,700 BTU/hour, and at 500ºF radiates 18400 BTU/hour. My insert is rated to output 44,000 BTU/hour maximum so when the stovepipe is at 400ºF (which is a pretty normal temperature in the burn phase) as much as 20% of the total heat output is coming from the stovepipe.

 

[Todd]

10-4 on that. My russian fireplace rules. Its a different design that what you have pictured above but same principle. It has been mostly 25-35 here for a month (a few days were warmer but not too many). I have heated my house at about 70 degrees all month on a little less than a pick up truck bed full of firewood. Maybe 2 face cord? Mine even semi heats my garage. its probably 60 out there.

I do 1 fire every 12 hours. The amount of wood per fire fits in a 5 gallon bucket. My firebox is only maybe 12"wx12"h. An arm full of wood. I split it VERY fine so I get a super hot fire that is OUT in 1 hour. Then I almost close the draft. Hours later the brick keeps getting hotter and hotter and hotter. 3 hrs after the fire.. almost can't touch the brick. 12 hrs after the fire, the brick is probably still 120 ish. I will get a temp gun soon and do some "studies" on it.

If anyone is building a NEW house or NEW addition, a masonry stove should strongly be considered. My first post here a month ago was a thread about my stove.. check it out for more talk on masonry/Russian fireplaces.

If anyone is local to Berkshire NY.. I will show it operating to you if you would like.

My apologies to the thread starter.. I know he said "besides Russian fireplaces"

Interesting, I will be looking forward to your studies. With my stove I've been on a 12 hr loading schedule as well and use the same amount of wood as you, but my stove is burning long and slow the whole 12 hrs. House temps have been hovering in the mid 70's. I get the same amount of BTU's as you but they are burned and distributed in a different way.

 

[arcticcatmatt]

^ Thats what your doing in a mason heater?

The point of a quick super hot burned is to get those BTUs into the brick ASAP. Its a cleaner burn.. alot less creasote. That gets the brick HOT and the coals inside (after almost closing damper) keep pumping even more heat into those bricks for hours and hours and hours.

The MHA says long slow burn = bad.

 

[Todd]

^ Thats what your doing in a mason heater?

The point of a quick super hot burned is to get those BTUs into the brick ASAP. Its a cleaner burn.. alot less creasote. That gets the brick HOT and the coals inside (after almost closing damper) keep pumping even more heat into those bricks for hours and hours and hours.

The MHA says long slow burn = bad.

My stove is designed for a long slow clean burn. That's what cats do best.

 

[arcticcatmatt]

^ Don't know what a "cat" is. Never heard a masonry heater design referred to as a "cat" before.

 

[Todd]

^ Don't know what a "cat" is. Never heard a masonry heater design referred to as a "cat" before.

Sorry I confused you, no masonry heater here. Cat stands for catalytic combustor. I have one in my stove.