Some possible improvements:
1. Make the tank 12'x16'x4' tall, with R30 wall and cover insulation (6"
fiberglass under 2" foamboard) and 2" foam beneath and a $50 20'x24'
folded EPDM liner and a 12,288xR30/608ft^2 = 606 hour time constant.
2. Lay a 4'x16' strip of PV panels (about 640 peak watts) along the north edge
of the cover, with a $ 16' length of 30" round poly film greenhouse duct
laid flat on top of the panels. Pump water up through the duct during the
day, and let it drain down at night.
3. Make a 16' (EW) by (y=) 11.3' tall foamboard reflector with an approximate
4' focal length (y^2x, aimed at the southern horizon), starting at the
north edge of the cover (0,0) and line the underside with reflective Mylar
film, using axle grease for glue.
4. Make a sloping clear polycarbonate south wall with 4 $0 4'x12' sheets of
Dynaglas greenhouse roofing running from the south edge of the cover (12,0)
to a point 8' from the north edge of the cover and 11.3' above it (8,11.3).
Enclose the endwalls with flat polycarbonate.
5. Collect about 1280 W of peak PV power and 10 kW of water heating with
a grid-tie inverter near the PV panels and a single high-temp hose to
the house with bidirectional flow and a fan-coil unit or radiant floor
and a 55 gallon drum with 300' of 1" pipe inside to act as a domestic
hot water heat exchanger, in series with a greywater heat exchange drum.
Hummmm. Very interesting Nick! I printed a copy off to "cern" for a while
Couple of very good ideas there Nick. I got to do some head scratching to
see if your barrel exchange unit works any better than the 2 chevy pickup
radiators I got mounted in the heat ducts with a squirrel cage circulator.
They be doing a right fair job :)
In the spring I plan to take the backhoe and dig a 150 foot ditch about 4
feet deep and lay out and back 300 feet of pipe (I'll make this a closed
system as well filled with antifreeze and cut off the hot water and pump the
52 degree coolant through those same heat exchangers. Got to work on the
humidity factor though.
"Come by and sit a spell with me at www.volstate.net/~mitch/ "