Wood-Powered Hot Water

[Skip]

Does anyone have experience with heating a water tank with a wood stove?

I found this picture on google..


How would you get the hot water to the sink? ..gravity?

Any experiences would be much appreciated ..

[somewhereinusa]

How would you get the hot water to the sink?

The same way you always do. Not sure how the one in the picture works, but it's not gravity. The coil is below the tank. In really simple terms, as long as the water that is cold goes through something that is warm the water will be warmer. I doubt if the pictured one is very efficient. The round shape of the copper doesn't have much surface to contact the chimney. It would be really hard to make that configuration stay in contact. It would be much better to have the heat exchanger inside of the chimney or even better inside of the stove. But, that presents other, harder to deal with problems.
The basic idea is a good one, I just think it could be made even better.

[turf]

i was looking at 12v pellets stoves and off grid stoves for heating the bus. i decided otherwise, but here is a stove with water jacket for heating.



http://www.wisewaypelletstoves.com/

[Skip]

Originally Posted by somewhereinusa

The same way you always do. Not sure how the one in the picture works, but it's not gravity. The coil is below the tank. In really simple terms, as long as the water that is cold goes through something that is warm the water will be warmer. I doubt if the pictured one is very efficient. The round shape of the copper doesn't have much surface to contact the chimney. It would be really hard to make that configuration stay in contact. It would be much better to have the heat exchanger inside of the chimney or even better inside of the stove. But, that presents other, harder to deal with problems.
The basic idea is a good one, I just think it could be made even better.

Well I know the one in the picture is not gravity fed ..I just thought that it could work if i raised the holding tank to the ceiling. I was looking at this old steel RV water tank that's like 4'x1', and its shaped like a long cylinder, which I thought could fit well into the curve of my ceiling.

..do you think the copper coil could withstand the heat inside the flue.

My friend put an old water heater tank directly on the wood stove and is gets really hot, after about an hour it's spewing boiling water out the top . so I thought maybe a coil could work better at keeping the water hot but not boiling.

[bansil]

I don't know how the one pictured works

I would have to agree on not very much heat exchange due to not enough surface contact

Also w/o a pump I don't see how water would circulate on it's own, heck the outside of the barrel and the copper lines would be about same temp from the single wall chimney, depending on the fire in the box, the radiant heat would make the whole thing warm

it's pretty though...maybe it's just used to make tea

[Skip]

It's thermosyphoning.

[bansil]

Originally Posted by Skip

It's thermosyphoning.

I see the concept, there is just no way that those 2 pc of tubing are different temperatures that close to the stove pipe to allow the siphon acting...I don't think (that is my disclaimer )

I wouldn't touch either of them after that stove has been on awhile

[roach711]

I like to re-engineer a solution as much as the next guy, but it might work better if the water tank was set directly on the stove like a giant tea pot.

It is very stylishly done though.

[Malkieri]

I would guess that this is a Coffee and/or tea machine. I assume it is in the kitchen area due to the food jars laying about, but it is not over a sink. This would imply that it is not a water heater, also the fact that it can't be more than 2-3 gallons. Other evidence I see is the manual coffee grinder (green arrow), hanging coffee/tea mugs (blue arrow) and the distance the tap is from the counter (red arrow). Also there seems to be some dark staining on the wood right beneath the tap, i.e. spilled or dripping coffee. Add in the seam along the bottom of the tank portion about 6 inches up from bottom and it looks like a modified commercial coffee maker like you see at hotels and such. It probably "percolates" like those old style coffee makers with the bubble window on top.
This makes more sense to me anyhow.

[bansil]

Watson....you might be onto something

[Malkieri]

Trust a caffeine addict to see the coffee maker..lol

[Redbear]

Originally Posted by bansil

I see the concept, there is just no way that those 2 pc of tubing are different temperatures that close to the stove pipe to allow the siphon acting...I don't think (that is my disclaimer ) . . .

The heavier weight of colder water near the bottom of the tank would push itself out into the coil, displacing the warmed water in the coil up to the top of the tank. I think drain-back solar hot water systems work in a similar fashion.

HOWEVER, you will notice that the bottom of the tank attaches to the top of the coil, and the top of the tank attaches to the bottom of the coil. This means the thermosyphon effect within the coil is fighting the thermosyphon effect withing the tank. The tank would probably win, with more mass of water and probably a higher temperature differential from the top tube to the bottom tube. But I think the flow would be more efficient if the top of the coil went to the top of the tank, and the bottom of the coil went to the bottom of the tank. That's my opinion, and it is certainly worth at least the ØØ¢ that you paid for it.

[roach711]

Originally Posted by bansil

Watson....you might be onto something

Good eyes there. Well done!

[Skip]

Originally Posted by roach711

I like to re-engineer a solution as much as the next guy, but it might work better if the water tank was set directly on the stove like a giant tea pot.

It is very stylishly done though.

Yea my friend did exactly that for the bathtub in his green house, and if you walk in the front door at the wrong time you could be covered in boiling water that spews out of the pressure release valve.

Originally Posted by Redbear

The heavier weight of colder water near the bottom of the tank would push itself out into the coil, displacing the warmed water in the coil up to the top of the tank. I think drain-back solar hot water systems work in a similar fashion.

HOWEVER, you will notice that the bottom of the tank attaches to the top of the coil, and the top of the tank attaches to the bottom of the coil. This means the thermosyphon effect within the coil is fighting the thermosyphon effect withing the tank. The tank would probably win, with more mass of water and probably a higher temperature differential from the top tube to the bottom tube. But I think the flow would be more efficient if the top of the coil went to the top of the tank, and the bottom of the coil went to the bottom of the tank. That's my opinion, and it is certainly worth at least the ØØ¢ that you paid for it.

Good observation!

[roach711]

Originally Posted by Skip

Yea my friend did exactly that for the bathtub in his green house, and if you walk in the front door at the wrong time you could be covered in boiling water that spews out of the pressure release valve.

He aimed the pressure relief at the front door?

[Skip]

Originally Posted by roach711

He aimed the pressure relief at the front door?

Hahaha yeah ..that's what I thought too