Geothermal systems come in three main categories.
- Open loop – Water is drawn from one well, the heat extracted (or added if using for AC) and then the water is returned to another well at least 100 feet away.
- Vertical closed loop – Well holes are drilled into the ground and heat transfer pipe is inserted. The well holes are filled with grout and lines filled with a food grade antifreeze.
- Horizontal closed loop – Pipes are buried in the ground in trenches or a large area. pipes are then added and filled.