Originally Posted by dirtydeeds
As a steam fitter, let me add that I like the heat exchanger idea. I'd use water past the wood stove. Leave it open to atmosphere somewhere. (even just a fill point) You don't want to build a bomb.
I like the open to atmosphere idea (maybe using a baffle box so vapor escapes, but not liquid), but I wouldn't use straight water because of corrosion and potential for freezing. I like the oil idea because of its higher boiling point, but propylene glycol could be used, too.