What if you only have low or moderate temperature wells?

Geothermal Heat Sources:

1. Reservoirs of 350 F - converts to steam efficiently to drive a turbine directly
2. Reservoirs 230-350 F - binary system is used; water heats fluid with a lower boiling point
3. Reservoirs below 230 F - binary system with heat sink; ambient air or surface water temperature must be 100 degrees lower.

Heat Pumps
A heat pump is a mechanical device that transfers heat from one source to another. Ground-source units pull heat from the earth and transfer it to homes or buildings. Heat pumps (despite their name) can provide both heating and cooling. The cooling process is simply the reverse of the heating process: heat is taken out of a building and returned to

Costs Comparison Geothermal Heat Pump vs. Conventional Heating System:

Initial Installation: $7,500 ($2,500 per ton of capacity so typical residential size 3-ton unit) where a conventional system approximately $4,000.

Lifespan of System: 20-30 years.

Annual Operating Costs: typically 25% to 50% less energy than conventional systems,

How does Ground Source Heat Pump Work with Systems in Existing Homes?
Source: Energymatch.com

Geothermal Resources:

1. Geothermal Resources Council (http://www.geothermal.org/works.html)