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re: wood stove
27 jun 1998
peter kariher wrote:
>the points to remember when installing a woodstove are to not have any
>horizontal sections or turns in th stack. these will slow down the
>gases.
why not slow down the gases and allow them to give up their heat?
>the next set of tricks are to use black pipe to the ceiling or 8 ft
>mark and go with a tripple wall stove pipe to the roof outlet.
why not make a counterflow heat exchanger with double wall pipe
with flue gases going up the middle and outdoor air coming down
between the pipes?
>this will keep the gas hot until it exits the roof.
and prevent desirable condensation...
>remember from chemistry pv=nrt. so if you extract too much heat
>from the gas in the stack, the gas will contract in the stack
>and not allow the stove to draft properly.
remember from physics (and measurements) that warm air rises,
and cfm = 16.6 av sqrt(hdt) in a chimney.
>keeping the stack hot will also cut down on creosote formation.
creosote formation seems fine, if it runs back down into the stove.
>also, make sure the wood you are using is dry and seasoned.
the wetter the better for heat transfer in a condensing chimney, no?
>the actual volume of air necessary for the woodstove to operate
>properly is realivly small... i compute around 10 to 20 cu ft
>per minute as an average stack flow.
ok... a 6" pipe has an area av = 0.2 ft^2, so with an 8' chimney,
20 = 16.6x0.2xsqrt(8dt) makes dt = 5 f. a small temperature rise.
nick
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