[Greenbuilding] solar heat collection

[Clarke Olsen]

   I am putting together a system with tilt-adjustable panels and a 1000 gal storage tank, in the hope of collecting
and storing heat year round. The 1400sqft house has radiant tubing in a 3" concrete floor sitting on 1/2" foam over
a crawl space. The boost from the tank temp to hot shower is handled by Eemax 6.5kw point-of-use instant water 
heaters. The floor circuit also has an Eemax booster. My plan is to run both the domestic hot water and the floor 
circuit through heat exchangers in the 1000 gal storage tank. 
   My question is: should the storage water run through the collectors directly in a drain-back configuration, or is a
closed-loop, heat exchanger be preferable? This would make 3 sets of loops in the tank, with the collector circuit
on the bottom.
Clarke Olsen
373 route 203
Spencertown, NY 12165 
USA
518-392-4640
colsen at fairpoint.net