A heat exchanger.

[ForgeCorvus]

It might be prudent to braze the connection on any pipe you are using, solder melts around 450°c where as brazing is around 600°- 900° , which with the close proximity of the stove might not be a bad idea.

J

But if its running an unpressurised water system, it'll never get over 100 c (as long as it doesn't boil dry).

[poppypiesdad]

More thinking of the radiant heat from the fire , especially if he wrapped the flue with a coil .

[ForgeCorvus]

More thinking of the radiant heat from the fire , especially if he wrapped the flue with a coil .

I see where you're at now.

Welded stainless would be the nutz...... But that requires either a skillset or a budget

[lightningxl]

Article in motherearth magazine.

http://www.motherearthnews.com/diy/wood ... dztak.aspx

[happyhacker]

A flue system is not practical and given the length of flue available would not produce hot water very quickly. The idea of using copper is that I can solder the components together. I have no intention of modifying the burner itself. If I use 15mm copper pipe I wonder if the natural conduction will move the water through but I suspect it will. That way I get more piping in the exchanger.

[matthopkins]

Not wanting to be rude but your missing the point of keeping the coil to only two turns. Its small in size and its the small bore of the pipe that heats the water quickly. it needs to be small as a lager amount of water takes longer to heat and moves as a large volume in one go, failing to pull cooler water through in a constant stream
This is a tried and tested method as ive been running this way for many years. The stove that you see in my youtube vid has an internal coil made from black iron pipe (thick walled gas pipe). Im able to run such a small fire in the burner box as to heat the water for a shower without heating the boat, its ideal in summer.

Maybe an easy option would be to get a tank and tap fabricated and either sit that upon or touching the fire? Take longer to heat but would work

[happyhacker]

Matt, the other issue with my flue is that it's already in place and not going to be dismantled.

[matthopkins]

Matt, the other issue with my flue is that it's already in place and not going to be dismantled.

No need to dismantle your flue. Plumbers use a spring like thingy that they insert in the pipe before bending, cant remember what its called but attached to a bit of string it can be pulled out after bending.
Insert one of these and bend it round the flue in situ, make sure you buy the softer copper pipe and it wont crimp. Your flue is large enough to do this. If you add compression fittings on each end of the coil and you have no need to solder, if they work in a household system no need to doubt them working here.

edited to add: Looking at the size of the collet on your stove this is more suited for what i suggest, not only will it be supported but resting on two surfaces, better heat transfer.

[poppypiesdad]

Matt, the other issue with my flue is that it's already in place and not going to be dismantled.

No need to dismantle your flue. Plumbers use a spring like thingy that they insert in the pipe before bending, cant remember what its called but attached to a bit of string it can be pulled out after bending.
Insert one of these and bend it round the flue in situ, make sure you buy the softer copper pipe and it wont crimp. Your flue is large enough to do this. If you add compression fittings on each end of the coil and you have no need to solder, if they work in a household system no need to doubt them working here.

edited to add: Looking at the size of the collet on your stove this is more suited for what i suggest, not only will it be supported but resting on two surfaces, better heat transfer.

Pipe bending spring , and good luck getting it back out the pipe afterwards as they are a pita.

J

[matthopkins]

Best thing mate is stick to using pots and pans