Hot Water
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I think anyway you can safely heat DHW or hydronic, using a wood stove or fireplace is a great IDEA. Whatever it takes, to save money in this Economy. I will be installing a fireplace or two later this spring, and I am seriously thinking about adding a device to heat my (DHW) domestic hot water. But, I will be doing alot more research on it first.
I would think it would cause really bad creosote build up due the water cooling down the gasses. Maybe not though as long as the water is hot to begin with. Plus looks like it could turn into a expensive project with running another pump and all the fittings.
One thing that seems to be consistent when it comes to the discussion of heating water with wood, and that is the fact that cooling the flue gasses with water will create creosote deposits. I would think that this device would do the same. I hope someone with experience with this particular device will speak up.
The most promising systems seem to be the ones where the heat exchanger is in the firebox closer to the heat, or mounted to the side of the stove where it will not be exposed to the flue gasses. None of these are ul approved that I know of (someone please correct me if I am wrong). Most people do not understand the extreme power of steam pressure that can be generated by these when not installed and used properly, so there is reluctance by regulating agencies and insurance companies to approve these things.
The most promising systems seem to be the ones where the heat exchanger is in the firebox closer to the heat, or mounted to the side of the stove where it will not be exposed to the flue gasses. None of these are ul approved that I know of (someone please correct me if I am wrong). Most people do not understand the extreme power of steam pressure that can be generated by these when not installed and used properly, so there is reluctance by regulating agencies and insurance companies to approve these things.
Yeah, yeah, yeah I know, I kniow, it's going to be expensive, it's going to cause lots of creosote, the ones on the side of the stove are better, it's going to blow up and won't be insured.
Has anybody used one?
Has anybody used one?
OK, Just as long as you are aware of the risks.
Now, I don't have one, but have been searching the internet a long time for water heating options, including wood heat, and I will say that this is either a new device, or well hidden, as this is the first time I have seen them after searching off and on for years, so it might take a while to find someone who has experience with that particular unit.
There are a few in here that have used the loops inside the firebox, use the search to find their comments.
I assume you have seen this article.
http://www.woodheat.org/dhw/dhw.htm
There are a lot of people that could use a simple, safe, inexpensive way to heat water with wood. I would like to see something like this work well, but I don't have the dollars to be the trial rat.
Now, I don't have one, but have been searching the internet a long time for water heating options, including wood heat, and I will say that this is either a new device, or well hidden, as this is the first time I have seen them after searching off and on for years, so it might take a while to find someone who has experience with that particular unit.
There are a few in here that have used the loops inside the firebox, use the search to find their comments.
I assume you have seen this article.
http://www.woodheat.org/dhw/dhw.htm
There are a lot of people that could use a simple, safe, inexpensive way to heat water with wood. I would like to see something like this work well, but I don't have the dollars to be the trial rat.
awoodman
Member
I to have been searching and very limited info on this subject. But having a 40-50 gal tank next to and above the stove seems like an excellent idea. I have posted the question before about CONDENSATION of cold water coming into the fire box. No answers yet................
drizler
Minister of Fire
If nothing else it seems like they are pretty proud of that simple piece of steel. I bet you would never see the payback just like most of the instant hot water rigs you see sold out there. I bet you would be spending a dollar to save a dime.
I'm not sure I buy this cooling the stack temperature will cause creosote. I hope Craig, Corey, and some of the other experts chime in on this.
In order to get creosote in your chimney, you have to have wood gases/particulate flowing through the chimney. Then the chimney has to cool enough to let this stuff condense on the walls. I think you guys are too concerned about the temperature.
I have read posts on here where catlytic stoves have stack temperatures as low as 150 degrees. Thats pretty cold but they don't fill up with creostoe because there isn't anything in the exhaust to form creosote.
I would think that as long as your stove is hot enough for the polution control device(Cat or burn tubes) to activate, then the only need for a warm exhaust is to create a draft.
Does this make sense?
In order to get creosote in your chimney, you have to have wood gases/particulate flowing through the chimney. Then the chimney has to cool enough to let this stuff condense on the walls. I think you guys are too concerned about the temperature.
I have read posts on here where catlytic stoves have stack temperatures as low as 150 degrees. Thats pretty cold but they don't fill up with creostoe because there isn't anything in the exhaust to form creosote.
I would think that as long as your stove is hot enough for the polution control device(Cat or burn tubes) to activate, then the only need for a warm exhaust is to create a draft.
Does this make sense?
I'll take that as a NO. Nobody here has used one of these.
Geez, get over all your speculations.
Geez, get over all your speculations.
wolfkiller
Burning Hunk
kenny chaos said:
Kinda testy hu? Let us know if you give it a try I am looking for hot water solutions as well.
SteveT
Feeling the Heat
karl said:
In general, yes, I think your assessment makes sense. But not as an absolute. No stove gets rid of all of the byproducts of combustion... it gets rid of most of them. So if there is enough cooling in the flue for the the gases to condense there will be some creosote deposited. It may be minor, it may be a lot but in any event colder flue temps work against clean flues.
Even recognizing that the OP wanted experience, not conjecture, I'll still offer another thought. Modern stoves operate around 80% efficiency, meaning "only" 20% of the heat gets to the flue in the first place. Say this device can recover half of that (probably not a bad estimate -- the best aerospace heat exchanges only get to 80% or so when operating exactly at the design point). So you would effectively be extracting an additional 10% of the energy out of wood or oil or whatever and for that you'd be installing a $500 device, plus installation and plumbing costs, and paying for the electricity to pump it back into the house. Not for me!
wolfkiller said:
I don't deal with presumptions well and I make no apologies for it.
I'll let you know what I find.
kenny chaos said:
I haven't used a premade version like the one you posted the link for . . . but I'm made heaters that are similar, as have many other people. All it takes is a vertical straight pipe, or a vertical coil around the stack. It does NOT require a circulator pump either, as it says in that webpage. All you need is a water storage tank a bit higher along with a thermosiphon hookup. I'd much rather keep things simple when possible, and having an aquastat and circulator for an otherwise simple system does not appeal to me. Creosote was never a problem as long as the pipe had some air space between it and the smoke-pipe. A piece of 1/2" pipe running up vertically 2-3' would heat 20-30 gallons a day easy with a smaller wood stove via the thermosiphon. Not as fast as an internal coil in the firebox, but works good enough.
I've had them around the stack, and inside the furnace. At present, I have one loop of 1/2" pipe that runs through the firebox of my wood-furnace, hooked thermosiphon to an 80 gallon storage tank. Only problem I have is in exteme cold weather - when the fire burns full bore day and night. It makes too much hot water, and if we don't use it, the TP valve keeps blowing off (which is pipe to the outdoors).
awoodman
Member
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What type of 1/2'' pipe did you use ( stainless ,copper) and do you have pics. This is what I want to do with an old 40 gal. tank.
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What type of 1/2'' pipe did you use ( stainless ,copper) and do you have pics. This is what I want to do with an old 40 gal. tank.
awoodman said:
The several that I've made that ran around the smoke pipe were from flexible 1/2" copper pipe. Flexible 1/2" water pipe can be bought at any plumbing supply; just costs a little more than rigid copper type L, K. or M pipe. Never had a problem with it. You can easily spiral it upwards around the pipe like a snake with no seams.
With pipes inside the firebox, I won't use anything but stainless. 1/2" black pipe will work for years, but if you ever get a problem with air bubbles/pockets in the pipe during a hot fire, the black pipe can burn out.
A good thermosiphon systems ought to have a few safeguards. A backflow check-valve at the bottom of the coil, a air-bleed at the top, and a TP valve in the top of the coil itself, along with the TP valve in the storage tank. Any old electric hot-water will work fine as a storage tank with no modifications needed.
One word of warning. If you plan to hook the storage tank into a second, fuel-fired heater - remember one thing. If feeding into a gas or LP heater, you must install a tempering valve. That, because gas hot water heaters have internal thermal fuses that will blow if incoming water is too hot.
You can only use thermosiphon if you mount the storage tank avove the coils. Only photos of a thermosiphon system is the one I'm using now - that is hooked to a firebox loop in my furnace. If you want to see that, ask, and I'll post. You can go to any of these links though and download installation manuals for factory made coils and thermosiphon. The factory made stainless loops or coils all cost around $150-$200. The Hot Rod can be made to fit just about any woodstove. Let me add, I'm not trying to sell a product. I made many homemade rigs that may of not looked great, but worked fine. My first house that I owned was heating 100% with a double-barrel, home-made wood-furnace - made from old 55 gallon steel drums. Heated our large farmhouse and also all our hot water for 10 years. It looked awful, but worked fine.
Hilkoil
http://www.hilkoil.com/product.htm
Hot Rod
http://www.yukon-eagle.com/Portals/0/manuals/Hot Rod Manual (Revised).pdf
awoodman
Member
jdemaris
I to have made some barrel stoves and have a doubble one in the shop now. It was a shame SOTZ went out of buisness their products were top notch compaired to the volkazang ones now.
I wonder if anyone has tried hot water type steamer to put humudity in the air by using a copper coil wraped arrount the flue pipe and then dump back into a pot sitting on top of the stove. It would get the water much hotter than just a pot sitting on the stove top.
I to have made some barrel stoves and have a doubble one in the shop now. It was a shame SOTZ went out of buisness their products were top notch compaired to the volkazang ones now.
I wonder if anyone has tried hot water type steamer to put humudity in the air by using a copper coil wraped arrount the flue pipe and then dump back into a pot sitting on top of the stove. It would get the water much hotter than just a pot sitting on the stove top.
smokinj
Minister of Fire
Heem
Member
FWIW, my insurance company has stated in no uncertain terms that they will not cover any damages caused by using a wood burning appliance to heat domestic hot water.
wolfkiller
Burning Hunk
Heem said:
Each company makes their own rules. In the long run, what your company told you means nothing in the broad spectrum of things.
I got cancelled two years ago because I have a heard of goats. They started a new "no farm animal" policy. So, I got a different company (Farm and Family). I'll add that neither the former or present company has any issue with my 1820 farmhouse having a wood-cooking Rumsford fireplace, a 1908 wood cook stove, two antique LP gas stoves, an oil sumer kitchen stove, two unvented LP heaters, a wood bake oven, a Hearthstone Mansfield woodstove, a Meyers Woodchuck # 4000 wood furnace, a woodheated hot water system, and a large three story barn also heated with a wood furnce (Thermocontrol model 500 from the 70s). They took pictures, gave me the rate, and I pay the bill.
smokinj said:
Hard to photograph since it's in a small room that's attached to the house and holds about 4 full cords of wood around the furnace. I can't get far enough from the furnace to get a good overall shot. Here's the best I can do.
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jdemaris said:
jdemaris:
A number of years ago, I tried a thermosiphon setup using soft copper coils wrapped around the firebox of my stove (see pic below), but was unable to get regular flow (using a tankless system with an inline heater core from a car).
I never knew why it didn't work... and I was experimenting long before the web existed, so couldn't make an easy search for design principles.
I may not have been elevating the core high enough, or an intermediate tank of some kind may be required that gravity feeds to the core instead.
I'd still consider running a thermosiphon to a storage tank, but I'm reluctant to *pump* water through the coils (to a baseboard heater or similar) for fear temperature shock might crack the cast iron firebox in an extreme set of conditions (even though I've been advised that wouldn't be likely).
I'd very much like to see photos of your thermosiphon arrangement... if/when you find the time to post them.
Thanks Very Much.
Peter B.
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Edit: Whoops... like ships that pass... thanks for posting the photos and diagram. If you might speculate on why I couldn't get my own 'toy' thermosiphon to circulate, I'd appreciate it. Thanks Again.
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