We mentioned the "loop" system. There are two types of loop systems used, open vs. closed loop. A closed loop system is more costly to install; however, requires almost no maintenance. While the open loop system is less expensive initially, it could require more maintenance over time.
The open loop system uses a geothermal heat pump that utilizes groundwater from a conventional well as a heat source in the winter and a heat sink in the summer. Overall, the closed loop is becoming the most commonly used system and is more efficient and reliable, as well as proving to be more economical over time. Closed loop systems use a network of buried high-density polyethylene (plastic) pipe which circulate a water/antifreeze solution from the ground to the heat pump.
The use of polyethylene insures the long life and reliability of the system. These systems are sealed and pressured to recirculate the fluid and to eliminate water usage. There are a variety of ways to install a closed loop system depending on the size of the yard etc: Vertical closed loops work well in many different scenarios. They are optimal when the yard space is not overly large. A drill rig is utilized to dig multiple holes and then the pipes are joined in a parallel or a series of parallel configurations. Horizontal loops can be installed using a backhoe or trencher with pipes being buried in parallel trenches.
This method works well in new construction where landscaping is not affected and where the land area is available. Directional drilling for smaller sized lots provide challenges for many Geothermal HVAC Co.'s however this is one of Chicagoland Geothermal's specialties. There are also pond and slinky loops which are very dependent on location.