Integral duct/heat store

[nick pine]

"yreysa" <gary@...> wrote:

> This is the fan curve for the Dayton 10 inch fan:
> http://www.builditsolar.com/Projects/SpaceHeating/Dayton10inchaxial.htm

> It does nearly 400 cfm at 0.1 inches of water, so if you could keep
the pressure drop for the whole system -- ducts, bends, entrance and
exit losses, storage flow losses, ... down to 0.1 inches of water
it would be a nice, low power choice. I think it will take a lot
of attention to detail to do this...

At 400 cfm, a 40 foot x 12 inch duct with about 113 square inches of
cross section would have a 40/100x0.1x400^2/12^5 = 0.026" H20 loss.

For a cheap DIY system, we might buy an unpunched $55 100 foot roll
of 12" polyethylene tubing from
http://www.greenhousemegastore.com/product/power-tube-tubing/fan-jets-power-tubes
and inflate 40' of it on the ground with gentle bends with
no kinks, as required in the final duct system.

Then wrap 10' of the ends in thin paper mache' (3 layers of newspaper
soaked in a dilute sodium silicate solution?) and let that dry.

Then inflate the 20' center section harder to a larger diameter and
wrap that in paper mache'.

The cut the big curved duct apart for reassembly indoors.

Then cut a slit in the center section and place 342 2-liter bottles
inside 18 feet of it with 1500 pounds of water in 18 84 pound 20"
diameter x 1' hexagonal horizontal bunches of 19 bottles with
circumferential wire ties and tape up the slit.

For smoother airflow, the bottle tops of the end bunches can point
towards the ends of the center section of duct, which should be
inflated to at least 2sqrt(6^2+10^2) = 23".

So, Paul, will this fit in your basement? If you are not prepared to
make a career out of refilling bottles, you could put another 3 18'
lengths of the 12" diameter duct into a 20' x 2sqrt(6^2+11^2) = 25"
diameter center section and raise both ends of the inner ducts 2'
and fill them with 3x18'xPi(6/12)^2x62 = 2644 pounds of water.

The upper duct could rest in a triangular fashion on an 2"x4"
welded-wire mesh ag fence shelf/sling m with supports s, like this:

...
m . . m
s m . . m s
s m ... m s
s ... m m m ... s ---
s . . . . s
s . . . . s ~12"
s ... ... s ---

| ~ 24" |

For more heat transfer surface, you could use more flatter ducts
on flatter shelves in a shoebox-shaped center section.

(John might enjoy putting 55 gallon drums inside a 30" tube :-)

Nick