[Cob] cob/earth oven also heating hot tub intake?

[tabitha and karl o'melay]

"your hottub is a (very large) safety valve" is true unless the 
overheat mechanism isolates the "fire loop" to stop the hottub heating 
process. (ref amanda's possible thermal syphon solution)

iron pipe is a good solution for a hot tub but plumbing can be tricky 
since the fitting connections (t-tape, pipe dope ect) usually leak when 
exposed to extreme heat and especially open flame.

i like amanda's idea of diverting the flue under the tub the best. in 
the end, it seems to pose the least problems. there are loads of hvac 
venting solutions that could be re-purposed to maintain tub 
temperature.

personally i have pondered for the quintessential solution to this 
problem while attempting to add solar thermal to the mix. nothing has 
gelled yet but it'll probably involve a stainless steel tube buried in 
cob, a kuznetsov stove and copper solar collectors. desired heat 
recipients will be household hot water, a hot tub, radiant heat in 
house extremities and the greenhouse.

regards

k-)