I am looking for a fireplace heat exchanger that I could use to capture heat to use in the radiant floor system.  The ideal fireplace would be a prefab drop in one but I could manage with a stand alone exchanger.  I hope to use a closed loop system to draw heat into the radiant floor system.  Anyone know of  a place that I could look?

Hi I am new to this forum and am not a builder yet but have done some extensive research on line for alternative building techniques including heating and cooling. I have seen some corn and pellet stoves with a water heating exchanger in them. I cant remember who or where they are but I think if you continue to search the web on some of these type of sites you will find what you are looking for. One thing I would worry about is the water boiling in the heat exchanger. I am not sure if your system is a closed system where you could use a heat transfer fluid like antifreeze or not.  I would look for a web site that has Magnum pellet stoves which I believe has a model with a retro fit kit for supplimental hot water that might suit your needs. Good Luck.   Pauly

I know that Acucraft fireplaces of Big Lake, MN makes a water loop for radiant and hot water heating. They mfg High efficient Fireplaces. link The Water Loop - Energy Saving Hot Water Coil



Eliminates winter hot water bills
Heats up to appx 2,000 square feet of in-floor systems
Supplement to domestic water tank
Whole house heating
Factory installed Water Loop - that you connect to your water lines
Stainless steel construction with 3/4" schedule 40 pipe
Meets and exceeds ASME, ASTM and US boiler code requirements

My personal experience with solid fuel heating appliances such as free-standing wood or coal stoves were good, but only with an air-tight unit with automatic combustion air control. Operating a stove without automatic temperature controlled draft air is a major compromise resulting in less initial cost with excessive fuel use/higher emissions. Fireplaces are highly inefficient unless there is enough mass of rock or brick to collect/radiate heat into the living space, but would not be my first choice as too much heat is lost up the flue. A brick/rock fireplace with an quality insert stove is a very good choice. As for pellet stoves...been there once, and would'nt waste my money on one more bag of pellets, as the cost was extremely out of line even compared to the ancient natural gas forced air furnace used for primary heat in that older home.

Location of any auxilliary heat unit is critical if you want it to perform well. Placement in a centralized location can heat most (if not all) of the home. I have heated my current home for 6 years with a free-standing unit and had not used the furnace unless the family was away on a trip, even with 30 to 40 below night temps and 20-30 MPH winds.

Choosing fuel types: I have heated with wood for about 15 years, coal for 4 years, and part of one season with wood pellets...burned 1,000 lbs (that's 50 bags @ 3.48/bag in 1998) in less than 4 weeks. Wood's cheap, but smokey/smelly. Coal is even cheaper, but a bad choice unless used in a rural area (very strong odor, heavy smoke and lots of ash). If you need to purchase/install a unit, carefully weight all costs including type/amount of fuel used, as payout can be very lengthy.

I would be careful with choosing any solid fuel heating appliance. Solid fuels, even in the better stoves leave a large footprint on the environment. The only way to reduce the emissions while burning any fuel is with complete combustion. A smaller hotter fire is the best way to achieve this (as with a pellet stove). Question is: how thick is your bank-roll? I've had an air-tight wood Earth Stove for 7 years, but haven't considered using it yet this season...easier to just set the furnace thermostat and only about 2 to 2-1/2 times the cost without any work. I don't have much free time these days, and I don't particularly enjoy the emissions I'm creating with wood heat, so the black iron might stay cold this winter, at least until the weather gets really nasty. My O/H/V gasoline powered generator will handle the furnace electrical and run most everything else in my house during a power faluire. My advice: if you don't heat green (solar/geo), don't change from conventonal methods such as natural gas/propane...not worth the expense, extra work, or the environmental impact. If you have the money to make a major conversion: go green, or stay with your current system...it will probably save you money in the long run.

Happy heating.

I'm currently building a heat exchanger for my Woodstock Soapstone Woodstove. Great woodstove, Lots of brick and soapstone make the heat very comfortable.($2500 new). The stove sits in a corner. I have tile on the wall to protect it from heat. My plan is to remove the tile and rebuild the wall as a heat exchanger. The plan is to Cover the wall with 1" rigid foam. Then steel mesh and pex tubing (just like in a normal radiant slab). Then make some forms and pour a 2" to 3" concrete wall. Then install new tile. This will be a closed loop to my solar water storage tank to help out on cloudy days. I will update when it is complete.

Eric -

I disagree on the environmental impact of wood versus gas/coal/oil. Wood, if harvested from a quick growing renewable source (such as poplar or pine) is carbon neutral and environmentally attractive. That is, you are emitting the same amount of CO2 the plant used to grow. Fossil fuels, on the other hand, have sequestered "ancient" carbon. When burned, you are releasing additional CO2 that was never present in the atmosphere.

In reference to the first posting, about being able to exchange heat from wood fired stove to manifold or tubing loop.  I ;d like to feed my 2000 sq ft shop Im planning to build with this sort of system.  I guess its something Ill have to manufacture myself.  The water loop looks like it would work.   Let me know what you ended up doing.  Thanks

I was at a house that had a heat exchanger built into a fireplace, the fluid then was used to heat baseboard heat in other rooms. The guy built this system about 20 or so years ago and said he never had a problem with it. He had a standard massonary fireplace, but for a grate he built (had built) steel tubing unde, behind, and over the fire. I think he used 3/4 inch black pipe. Not sure if it was an open or closed loop. But the idea seemed so common sense to me I had one of those, why didn't I think of that!!
I would have a big problem with a closed loop system, just seems like an accident waiting to happen. And what kind of temp can pex take before it might have a problem, even open loop, or what kind of tempering system would be usde to keep temps under control. Maybe a pump that would shut off it temps got to high ( open loop).
If it were a zero clearance what about the pipe between the inner and outer metal skin, that way the firebox is kept air tight (maybe for insurance) and firebox entegrity.

Posted By AUSTENNN on 30 Oct 2007 11:18 PM
I am looking for a fireplace heat exchanger that I could use to capture heat to use in the radiant floor system.  The ideal fireplace would be a prefab drop in one but I could manage with a stand alone exchanger.  I hope to use a closed loop system to draw heat into the radiant floor system.  Anyone know of  a place that I could look?

I did a little research with your dilemma and I found this site which you can check out for fireplace heat exhanger http://home-and-garden.become.com/fireplace-heat-exchangers

Hope this helps you. Good luck.