Ice free water

I think that the geothermal guys are on to something here but I would go about it in a completely diffrent way.  1) I would drill a well as deep as practical. 2) I would install 3" schedule 40 pipe to the bottom of the well with a end cap. 4) I would also run 3/8" or 1/2" copper or plastic tubing (air pipe) to the bottom of the well pipe and out a exit tee fitting at the top of the well pipe. 5) At the tee I would enter the bottom of the tank with the 3" pipe at 90* thru a bolt on manifold (toilet flange)and run the pipe half way to the center of the stock tank (6 I would install a small 12V dc air pump or compressor to the air pipe and connect that to a battery bank and appropriate solar array all to be controlled by a thermostat and a SPDT switch so you could use it in any weather as an areator.
     The air would be the motor that drives (circulates) the warmed water and the air would also bubble into the tank to keep the surface from freezing. The air pump would not pull much amperage so the array and battery bank would not have to be excessively large.
     I have a drawing of this system as I have been working on this for a while and If you e-mail me I will be glad to send it to you  -  oltoby @ sbcglobal.net  - please put ice free water in the subject line.
Jim C.