Types of Geothermal Heat Pump Loop Systems
There are three basic types of Geothermal loop systems installed by S&B Geothermal. Two of
these, horizontal and vertical, are closed-loop systems. The third type of system is the
open-loop option. Climate, soil conditions, available land, and local installation costs at
the site help determine which one of these is best. All of these approaches can be used for
residential and commercial building applications.
Closed-loop systems
Horizontal loops
This type of installation is generally most cost-effective for residential installations, particularly
for new construction where sufficient land is available. It requires trenches below the frost line,
usually at six to eight feet deep.
The most common layout is a slinky ground loop, a coil of plastic tubing spread out and overlapped in the trench. The slinky method concentrates the heat transfer surface into small volume, requiring less land area and shorter trenching. A compact slinky will reduce trench length by about two-thirds; an extended slinky will reduce trench length by about one-third. Specific design lengths will vary with the climate, soil, and heat pumps specifications.
Vertical loops
Vertical loops are installed when the land area is limited, where the soil is too shallow for trenching,
and/or as a way to minimize disturbance to existing landscaping. These systems are well suited for large
commercial buildings and educational institutions. 
A contractor bores holes (approximately four inches in
diameter) about 20 feet apart and typically 150–250 feet deep. Long, hairpin-shaped loops of pipe are then
inserted into these holes. The vertical loops are connected with horizontal pipe (i.e., manifold) placed in
trenches, and connected to the heat pump in the building. The objective of a vertical borehole is to install
a specific amount of pipe, not to reach a certain depth. For example three 200-foot boreholes are sufficient
if 1,200 feet of pipe is required.
Open-loop systems
This type of system uses well or surface body water as the heat exchange