Friday, August 17, 2012

Wood fired bath update

A new addition to the family-R2D2
It's a cheap, sheet metal -cooking stove, クキングストーブ

I had second thoughts on the rocket stove version.
It would probably cost 1/4 to 1/3  the price of
this little baby  to attempt a rocket stove, though
I probably will try it someday.

Nice and easy, drill 2 holes, no cutting or grinding of metal nor flesh.

Suspend the coil above the wood hopefully
the hottest area.

All ready to roll
cold water from the hose on the left
hot coming out the right

Looking good, but a little smoky, too close for comfort.

That's better

But what if it rains? Or snows, or hails or....forget about it.

Heavy tar and creosote drip on the coil and some out of
the intake and outlet as well.
Have to bend the inflow and outflow up on the outside
 and the drip will not continue.
Also have to put dirt or sand,  maybe a sheet metal spacer
 at the bottom under the grill.
It's the most vunerable area and prone to burnout,
 though I have seen some of these
stoves that get a lot of use.
 These guys really love their stoves, I mean really.
Though not something to do daily for sure.

And only used half a tool-basket of wood , which is pretty frugal considering.
Being that this was the first firing I kept the fire small and it took some time
to figure out the air mix.  It could definitely run much hotter.

On the performance side things were much better than the old BBQ grill for sure.
Temperature was much more consistent .
 Flow was still 1-2 liters per minute though
that will improve if I fire the stove hotter.

However it's becoming clear that this type of boiler
will never be have a really strong flow.
That's fine, I mean what can you expect
from a system that costs about 10,000yen

At 2 liters per minute it takes
about an hour to fill the 120 liter tub.
That's probably enough for 3 people to
wash and bathe before a refill.

What is needed is to re-circulate
the warm water from the tub
back to the boiler again
For that a cheap drill pump ドリルポンプ 
hooked up to the solar
should work nicely.

Next I'll fill the tub with cold water
and start recirculating right away
should improve things greatly.

I think this kind of system
would work best in conjunction
with a solar batch collector in a box
 or just a coil of black pipe
on a hot tin roof.

50 meters of 20mm pipe will hold
15 liters of hot water  of hot water
enough for a  decent 5 minute
shower, maybe longer if mixed
with  cold water...hmm

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