Re geothermal, I spent a lot of time composing a msg which got dumped before I could send it. -- Two ways generaly to go: drilling, and trench with coils. I like drilling But without expensive equipment you have a development problem.
See this item on ebay:
Build A Water Well or Geothermal Drill Drilling Rig - eBay (item 220413261413 end time May-22-09 04:01:51 PDT)
For $40, plans to build a well driller capable of being operated with either a tractor or bobcat. Requires a welder and a few standard tools. Interesting descriptive material here. Suggests a possibility for building a low cost well driller which if not useful as a final tool for geothermal drilling could be justfiied just on the basis of gaining experience.
You might look at the archives of NATIONAL DRILLER. One guy there slant drills holes from a shallow hole 6-ft square. Appears to me the above plans might be adaptable for slant drilling, and you could operate the driller with the hydraulic system of any medium size tractor or Bobcat.
Anybody thinking along these lines?
Glenn Ellis
glenne1949@aol.com