I have read some posts on "thermal batteries" or water heat storage. A year or two back I attended a "Preppers conference" which was very informative. Basically it is preparing in all sorts of ways for a hurricane Katrina or "natural or unnatural catastrophe". We talked about the necessity of water and what happens when electricity disappears. So there were seminars on digging wells and how to get water out of the ground and so on. My wife is also interested in either having a second well or at least reliable water during emergencies. And there are some things you can do. There are booster pumps, for example, that can boost water pressure to 50 psig. They can be powered off 12 or 24 volts DC using batteries and solar panels. So then I thought: I am already returning a constant water flow to the aquifer from my heat pump "wasting" the water. Why not store between 500 - 1,000 gallons of water above ground AND repump or recycle that water back to the house over and over ? For heat pump ?, cooking, toilets, washing laundry and showering ? What I need: 1) Emergency water that can be pumped from solar or batteries 2) the ability to boost daylight water temperatures of stored water 10 - 20 degrees during winter months (to increase efficiency) 3) the how to of building a copper tube thermo syphon solar water heating system. Thoughts, you creative people ?