simple low cost solar hot water

[southsidedelite]

use a shallow pond lined with black EPDM, with a tiny slope so pump
discharges in one corner, and hot water exits other side.
this is described in some detail by Nick Pine, veteran low cost hoe
made tinkerer designer and solar schemer who contributed so much to
alt solar thermal, alt energy, alt architecture newsgoups, also check
this direct link:
http://www.builditsolar.com/Experimental/DHWPond/Proto3/SolarPondDHW.htm
for low cost heat storage, some great ideas here:
http://www.jc-solarhomes.com/multi_tank_heat_storage.htm