rykertest
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| 09/26/2009 6:46 PM |
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| So I'm trying to figure out a good way to pull the heat from our wood stove at the center of the house to the basement. I hate to not use that free heat everywhere so maybe you can help me think through this?
I was thinking about having a vent built into the hearth right behind the stove. That way the heat that is created by the stove that is radiating outwards can be pulled or allowed to move downstairs. It wouldn't be hard to add that small amount of ductwork, but what would be the best way to move that heat? I do not have ductwork in the house so this will be a stand alone ductwork system. I thought about having a small fan inline that could pull the heat down, but does anyone have any other ideas on how to solve this problem? Thanks! |
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Rio
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| 09/27/2009 11:11 AM |
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I don't know if this is available or practical but I've often thought that if one could run a length of tubing in the flue, say a spiral either on the inside wall or possibly inside the chimney material, then one could use the hot water generated from that source for any number of purposes, from tying it in to a water heating system, to using it in conjunction with a hydronic heating system or, possibly in your case to take it to a reservoir and then run another coil to a radiator of some sort........
For your idea on the ducting going to the basement from an air to air heat exchanger at the hearth I would say make the duct as large as possible, as straight as possible, a round duct has less friction loss compared to other shapes and, I think that if you pull the air it is more efficient than pushing the air because of less turbulence but not sure on that............
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toddm
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| 09/27/2009 1:52 PM |
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There aren't very many good answers if the house and the stove exist.
An air-to-air HX would require a HX. I'd be reluctant to draw air around the stove itself for fear of screwing up the draft and circulating CO through the house. You could weld up a steel surround/plenum that could capture radiant heat pretty efficiently but you'd have to work at making it look like it belongs in your living room. (Not impossible. You could disguise it as a faux fireplace so the stove looks like a conversion.)
You could draw air off the top of the room and circulate it in the basement, assuming the layout cooperates.
Or you can adapt the stove to heat water and transfer heat hydronically. http://www.therma-coil.com/index.html Or here http://www.woodheat.org/dhw/dhw.htm for cautions and examples of jerry-rigged wood stove boilers. But DHW is the limited goal in each. You'd need to really load up your stove with coils to make a dent in space heating, at which point you risk cooling the stove enough to screw up its efficiency.
If you are willing to swap out the stove, there is always the outlaw answer. There are lots of modern, efficient wood stove boilers in Europe that put 70 percent of their heat in water. Buying one on eBay in Britain and getting it shipped here would cost you $3k to $4k. You will meet folks who look at you like you're putting a nuclear reactor in your living room. You can discount some of the Not Done Here horror for Don't Know How. The schematic on page 6 looks pretty safe to me. Translated from the English, an overheat situation opens a valve to dump city water (mains) to waste (tundish) through a HX that keeps things from boiling.
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rykertest
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| 09/27/2009 1:58 PM |
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hhmm...good replies guys thank you. I shy away from anything to do with the water addition, that seems like way more work than I care to do. While I know heat rises, I wonder if just having an opening for heat to naturally migrate would make any difference?
Todd, do you really feel that pulling heated air from the stove area would mess with the draft? I could always move the inlet a few feet from the stove to pull air down as opposed to right behind the stove. |
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toddm
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| 09/27/2009 2:34 PM |
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I am sure you could find a velocity low enough to preserve the stove's draft, but I doubt that it would work much better than drawing air off the ceiling.
woodheat.org on distribution http://www.woodheat.org/planning/heatdist.htm |
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jonr
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| 09/27/2009 9:08 PM |
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If the source and destination rooms are open to each other, then don't worry about the draft. Otherwise, use two fans/ducts, one for each direction (to keep from reducing the stove room pressure).
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rykertest
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| 09/28/2009 11:46 AM |
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| thats some good feedback guys thank you for the replies. |
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big hammer
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| 09/30/2009 9:43 PM |
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Pretty tough to get heat to go DOWN. And yes, a duct pulling warm air down will mess up the draft! It needs to be at least 20 feet away to minimize the effect. As stated, it is more effective to 'pull' the waarm air down, rather than push it down.
Would it be possible to move your stove to the lower level? Easily heat both levels with no problem!
Mark |
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rykertest
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| 10/01/2009 12:59 PM |
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Posted By big hammer on 09/30/2009 9:43 PM
Pretty tough to get heat to go DOWN. And yes, a duct pulling warm air down will mess up the draft! It needs to be at least 20 feet away to minimize the effect. As stated, it is more effective to 'pull' the waarm air down, rather than push it down.
Would it be possible to move your stove to the lower level? Easily heat both levels with no problem!
Mark
You make a valid point about pulling versus pushing, and I had not considered that. I still question how it can affect the draft THAT much, especially considering the basement and upstairs are open to each other. I think if the vent is far enough away from the stove it wouldn't be an issue. More thinking is in my future, and I may need some starbucks for this. :) |
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Brock
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| 10/04/2009 9:40 AM |
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As long as it is open between the two spaces you shouldn’t' have an issue and once you have an active draft going moving the air inside the space shouldn't affect it. We did a similar thing, but fortunately our wood burner was downstairs. I thought being open to the main floor the heat would just head up, but it didn't as much as I had hoped so I just added a 6 inch duct above the wood stove (10 foot ceilings) and ducted it to the opposite end of the house in the living room on the main floor with a simple 6 inch inline duct booster. It was amazing how much that made a difference and you couldn't hear it at all.
I would agree though, to pull the air down. It can’t hurt to try it with a simple 6 inch flex duct to see what it does. |
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Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1.8kw solar PV setup, 3400 sq ft |
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