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Blank Space
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Discussion Starter #1
These threads don't seem to get a lot of traction, but here goes.

I use a small wood stove, but it's in a back utility room with a concrete floor and some tile cement board around it for fire protection. There are two fans behind it to push air out into the house. That works well and it puts out quite a bit of heat for what it is. It even helps in the bedroom which is beyond two doorways and around a corner.

But I think it could do better with some help. There is one common wall between the utility/stove room and the bedroom, but it's concrete block (the old back wall for the house before the previous owners enclosed what was the porch). For a number of reasons, I don't want to open that up and add any sort of fans. For one, I don't want the noise from the washer when it's in use.

But I got to wondering about a radiator system. If I could put one or two adjacent to the stove to pick up the heat, pipe it to another radiator in the bedroom and circulate an oil, it might work out halfways decent.

I see hydronic baseboard radiator units for under $50 at a couple of places. Copper tubing is expensive, but I'd only have about 20-30' of it to complete the loop. What I'm not sure of is the heat pickup unit and the fluid. I'm thinking a motorcycle or mower/ATV type radiator standing beside the stove, or maybe two, one on each side and either mineral oil or maybe just anti-freeze.

Then there's the question of circulation. I'd probably need some sort of pump to keep the fluid moving, but I don't want it to use a lot of wattage.

Ideas?
 

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Senior Moment
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First idea... don't use oil. Too much of a fire potential there.


There are low wattage, hot water pumps being used on outdoor boiler systems. Look into one of those.
 

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Interesting idea. My first thought was also to see what design elements you could copy from the outdoor boilers. I don't know what they use for piping, but i know my mom's boiler system for her house uses flexible piping. I think it's PEX, than it would be cheaper and easier to deal with than copper. I'd assume you will want to consider insulating the pipe too.

I'd just run water in your system, unless you think there is a freezing risk. In that case, add antifreeze. I agree that anything with fire potential is a no-no.
 

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Senior Moment
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I've been looking into something similar here, but maybe a little more complex and larger. (I'm heating almost 3000 sq. ft.) In my case the radiators are already in my bedroom as the house used to have a boiler system throughout. I'm converting the majority of the house to forced air but can't get any ductwork into my bedroom so that will remain hot water heat.

The house went through a winter without use and nobody winterized it so the piping in the floors and overhead all froze and broke. I'm not going to replace the slab as that would cost about what I bought the house for... Or more. Those baseboard radiators in my bedroom survived though, so I'm going to use them.

My setup right now is a forced air wood furnace that has an add-on hot water coil in the firebox. (not installed yet) That hot water will fill a hot water tank, using a salvaged water heater for that, and then the hot water will be pumped through the bedroom radiators using the old boiler lines. It's a semi closed loop system. I'll be using a low wattage boiler pump on the cold return end of that closed loop. It probably won't be "hot water" but I really just want to take the chill out in my bedroom... Not crank up the temps so high I'm sweating while I sleep... 50-60 degrees would be great.


At some point I will be adding a propane or fuel oil furnace into the setup that will do the same thing. That way there is an automated backup if I'm not here to feed the wood furnace.... At least that's the plan.
 

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My friends uncle had a large barrel type wood stove ,he had a plumber friend hook up some baseboard heating panels to a coil of copper tubing wrapped around the stove itself and the stove pipe, close the the top of the stove--the guy plumbed it up in a manner so any steal could bleed off safely through a vent,and used convection to circulate the water through the system with no pump needed.....that heated his entire basement quite nicely,it was about 30x30 feet and walls were painted uninsulated cinder blocks.

Personally I have seen a home made "boiler" from a converted wood stove explode ,luckily my friend who "designed" it and I were not in the shed it was being used in when it decided to blow--we think ice formed in the plumbing after the fire died out the night before,blocking the venting valve--and BOOM!..pieces of pipe were stuck in the wooden walls near the stove they blew apart with such force !..:eek:..
Best to have someone with proper knowledge at least look over any home brewed heating systems involving hot water !..

I know a farmer who made a "heater" for his livestock barn out of an old truck engine,a 235 Chevy straight six..he cut the front of the truck off at the cowl,and butted it against the back of the barn--took the dash out of the cab,and mounted it on the rear wall,and he hooked up the ignition switch,and choke cable to the engine so he could control them from inside the building...also a hand throttle,so he could boost the idle speed up a bit too..

He plumbed a large radiator from a semi truck to the engine,placed it high up in the rafters pointing down at the floor,and used an electric fan from a car to blow the warm air down to the floor area...he used a 195 degree thermostat and insulated all the piping to the engine with foam pipe insulation to avoid heat loss...

He also decided after trying the system out and being pleased at how well it worked,to add 3 alternators to the engine,driven by the fan belt with a jack shaft--he put several old car headlamp bulbs in the ceiling he got from a junkyard,to light up the barn,it worked pretty slick..the barn had no electrical wiring,so it was flashlights or nothing after dark !..

The heat was enough to make you sweat after a half hour of running time,and the barn was about 50x50 feet with a loft around 3 of the sides for hay storage..he estimated he burned about 3 to 5 gallons per day to keep it comfortable in there..

I have seen a few garages heated with an electric or propane water heater,hooked to baseboard heat panels too,that worked quite well,in a smaller well insulated garage..
 

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Blank Space
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Discussion Starter #6
Thoughts on fluids other than water is that they retain and transfer heat better and are not corrosive. That's why I mentioned mineral oil (not sure about flammability) and coolant, maybe an RV type like some of you use in tires.

I could use PEX type pipe/tubing, but it takes special connectors and tools that I don't have. I'm thinking PVC once I get away from the stove, then back to copper to mate to the radiator(s). That would be in foam pipe insulation where practical.

If I can find mower/ATV radiators about 8 to 12 inches square, I could use one on each side of the stove mounted inside standard sheet metal heat duct with copper pipe between them.

I found a couple of circulation pumps that might work in the $50-100 range in both 12V and 110V versions. I can supply the 12V without much trouble.
 

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Blank Space
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Discussion Starter #8
Instead of mower/ATV radiators, what about 1/2" copper formed in multiple "S" coils inside the sheet metal heat duct? Then maybe coiled around the stove pipe for a foot or so at the top of the stove.

Would that pick up enough heat, but not too much?
 

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My uncle designed a simple system that worked out pretty darn good.

He had a stand alone wood burning stove, much like you're describing, in the center of their two story home. After completing the home building, he decided he wanted to use the wood stove to heat the bedrooms above it. He built somewhat of a decorative/functional enclosure around the wood stove, enclosing all but the front and had a cutout for the chimney to pass through. There was a few inch clearance all around between the stove and walls.

Hooked up to the enclosure was an individual 6" or 4" duct, uninsulated, for each of the four upstairs bedrooms. I'm not sure how he ran the ductwork through the walls, but in your case you might be able to pass it into a crawl space or something. On each duct was a low wattage duct booster, which is basically an inline fan used to boost airflow through a duct that otherwise doesn't get much airflow. Something like 100 or so CFM.

In each bedroom was a cheap wall thermostat. All the T-stats did was turn the duct booster for their respective areas.

It worked INCREDIBLY well and didn't cost much.

EDIT I just re-read your post and noticed the concrete floor element. Need to figure a way to run ductwork... Can't go down, right? :tango_face_sad:
 

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Blank Space
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Discussion Starter #10
Can't go down. The wall in question is concrete block all the way up, so no ductwork, but I could drill for 1/2 pipe/tubing like I did for the water lines in other area.

I could also go up and over this one wall through the attic. That would be easier to do with pipe/tube than a piece of duct. I could enclose the pipe/tubing in something for insulation purposes.


Thought about 1/4" copper tubing also which would cost less and be easier to form/coil, but I'm not sure about heat transfer and fluid flow.
 

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I just happened onto this thread and was reading it, pretty interesting, sounds like your wanting to make a boiler type system alright and just water and a little correct type boiler anti freeze would help. I worked at a Htg & A.C. wholesale place for 12 yrs. and the owner was the most knowledgeable boiler man within 100 miles and pretty much stayed busy helping people with them as well as industrial type systems 365 days a year. I wouldnt use anything but copper for dispersing heat for sure but thats just an opinion but man I remember the water in his home system when we replaced the pump in it and his water was solid black! and he said " thats just fine" it had been in it for 15 or so yrs. We were also distributors of Bell & Gosset circulating pumps ( thats the only brand he would use or sell) but boilers are becomming extinct because of installation costs and just finding someone who actually knows much about them anymore w/how many loops you are going to have in your system and all that. One thing is for sure tho and that is a good hot water system is the best htg system you can have, they are silent, they heat everything in the room/house as in you wont sit on a cold chair or couch and you will never know how cold it is outside untill you go out he used to say. Good luck with your hillbilly system from a West Virginian ! lol.
 

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Blank Space
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Discussion Starter #13
I'm not sure about that. It's an option to look at, but the fan noise might be an issue if it echoes through the duct.

'Course in Summer, I have a window AC unit, so I doubt a duct fan would be any louder than that.
 

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I'm not sure about that. It's an option to look at, but the fan noise might be an issue if it echoes through the duct.

'Course in Summer, I have a window AC unit, so I doubt a duct fan would be any louder than that.
Those air duct booster fans are incredibly quiet to begin with. Insulated flex ducting, coupled with mounting the fan in the attic, will eliminate all motor noise completely.
 

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I once saw a rig consisting of a semi truck radiator mounted over a free standing wood burner. The radiator was attached to hinges. Copper pipes ran to the other side of the house into some sort of room radiators. When they wanted to heat those rooms they lowered the semi radiator so it was a few inches above the top of the stove. When they did not want heat in that far part of the house they just raised the radiator. Not sure what was in the pipes. Don't believe there was a pump but I'm not sure.
 

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Senior Moment
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Because of how convection works, (Science class if you recall "heat rises") if the path of hot fluid is upwards a pump may not be needed but may be "suggested" to keep things flowing optimally. If the heat is expected to travel up, through a wall and then back down for baseboard radiators, or just down from where your woodstove is to the floor, you are gonna need a pump.

In the case of the system I'm building the flow from the coil in the furnace to the tank will fill the tank via convection with no problem, It's adjacent and the pipe is running uphill at better than 75 degrees off horizontal. But after leaving the tank near the ceiling it has to go down to the level of the slab to go under the floor and then up above floor again to the radiators... This makes the system need a cold water return pump or the hot water would just stall at the tank. The pump is in the cold/return side just to keep it from absorbing heat that is better used elsewhere.

Another thing about this setup that may prove to be desirable depending on your setup. Earlier I called it a "semi-closed loop". My residential water system will be setup to keep the loop full at all times. In this case a backflow preventer needs to be installed so none of that loop water gets back into my drinking water supply.
 

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Blank Space
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Discussion Starter #17
^^ I was kicking around the idea of a tap somewhere to pull out hot water for ramens, soups, instant coffee, hot chocolate, etc., but wasn't sure how to keep the system supplied and avoid air locks.
 

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I would look into some books on this as now its becoming a thing with off the grid types , my brothers house we took out all the black pipe and radiators and the old oil fired steam boiler and now use a gas/wood hydronic system ( hot water ) all the lines are pex , lots cheaper and easier to install than copper , but a little harder to insulate ( have to wait till you run some hot water thru it so it uncoils and straightens ) if it was me I would build a tank on the top of the firebox ( 1" air gap it so it won't boil immediately ) and run a real boiler pump to circulate it and it will use the tank as a heat bank , since your using a constant burn firebox constantly recirculate it , no need to cylcle it like a gas type which batch heats the water then pumps the hot water out to disapate it then returns the cold back ( when set up properly its supposed to do this once a hour ) you can use a old hot water heater as a auxillary heat tank as they can see 75-150 Psi and 210* before setting off the OPV and you can make up a heat exchanger for domestic hot water ( you should keep the water systems seperate

as for shop heat my buddy who owns a trucking company has a co gen unit , its a big cat NA gas/diesel he uses to generate electricity for the shop and sells the excess to the electric company and the heat from the unit in the winter is used to heat the shop in the winter , in the summer the unit also runs the compressors for the a/c units , it was expensive to set up but paid itself off in 5 years
 

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I just remembered something that I havent heard of in years, we used to sell this small duct called "wall stack" and it was like 2 1/4 x 12 & 14 in 2' joints that went in the wall studs. Pretty strange stuff, but we did sell a round duct fan that was 6" round for long runs of 6" round duct pipe. I havnt thought about this stuff in a cpl decades.
 

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check out radiant floor heat with pex..........simple and easy to do. Very silent. Standard cheap water. The pex connectors are not bad. you would only need a few and there are some cheap crimping tools for the few connections you would be doing. Its just another option to consider. OH and your bare feet would be warm everytime they touched the floor.
 
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