open loop system

With open geothermal ground loops, rather than continuously running the same supply of water or antifreeze through the system, fresh water from a well or pond is pumped into and back out of the geothermal unit.

Both an abundant source of clean water and an adequate runoff area are required for a successful open loop system. While double well designs can be economical, use of open geothermal ground loops is generally discouraged and even prohibited in some jurisdictions. Water quality is key to an open loop design as mineral content and acidity can quickly damage geothermal units.

Also, improper installation or runoff management of an open loop geothermal system can result in ground water contamination or depleted aquifers.