|
|
re: t.e.s tank/application: (was: parafin and solar thermal storage-non building)
3 jun 1997
douglas s. gondor wrote:
>...can one expect a 200f constant temperature at the crop dryer's heat
>exchanger/fan, from the tes tank, providing suitable pump and temperature
>regulation throughout, over the 16 hour period?
obviously not, with a water store, without a heat pump.
the water just gets cooler and cooler...
>if not then a phase change material (pcm) is mandatory...
i wonder why these particular crops care exactly what the temperature is,
or whether they need to dry all night, vs just during the day. and why not
include the crops themselves in the thermal mass, above the water tank?
>...i like the idea of the water in a $0.02 per gallon water tank...
for a 40x80x700' tank in the ground, at 1976 prices, including excavation...
>...does this include the cost of r20 insulation??
r20 insulation costs about 25 cents/ft^2, as 6" fiberglass. epdm costs about 30
cents/ft^2 in 20' wide rolls. a 20' cube has 2400 ft^2, ie $1320 for rubber and
fiberglass only, coincidentally about 2 cents per gallon, but with nothing to
hold it up/in or protect the insulation from the weather. some people figure
deepish earth has r10 insulation, a resistor in series with a constant temp of
about 55 f, with larger and larger areas as the resistance extends deeper into
the earth.
>...can i maintain a constant 200f through my crop dryer
>at night using the tes tank?
you'd need a lot more water, or magic.
>also can't i get a temp swing of 210f-70f, or is this too much to hope for?
you might, but what would you do with that 70 f "heat"?
>24 feet across by 17 feet high = 7686 round tank.
like a cheap circular metal swimming pools, but taller, with a smaller surface
to volume ratio... a 20' d x 20' high tank would have pressure p = 20x0.43
= 8.6 psi and hoop force pr = 8.6x10x12 = 1032 pounds per inch at the base,
eg 1000 psi with 1" thick wood. a 20' octagonal or cylindrical tank might be
made with 100 overlapped $5 sheets of 3/16" osb and a 0.020" metal wrap around
the base, and an epdm rubber liner, and one flat piece of rubber on the bottom,
with the outer bottom edge looking like this:
.
.. f
... i
... b
water eo. e air
psm r
dbe g
mot l
rsa nut a
inside ubl 2x4 s outside
b b e r s
silicone rubber
...epdm r u b b e r
...osbosbosbosbosbosb
2x4
bolt
polyethylene film
earth
nick
|
|
