One of the major hurdles for this technology is reaching a consensus as to what it will be called.
A great many names have been used in the past with confusion resulting for the public and the
industry. The following figures outline the major residential system types and the various names
used for each.
Three terms are in use to describe the technology in general: geothermal heat pump (GHP), geoexchange (GX) and ground-source heat pump (GSHP). The first two are typically used by individuals in marketing and government, and GSHP by engineering and technical types. The terms appearing in bold in the figure to the right will be the ones used throughout this text.
Ground-coupled systems have been widely used since the mid-1980s. Currently, horizontal systems constitute about half of the installations, vertical 35%, and pond and "other" approximately 15% (Kavanaugh, 1995).
Groundwater systems have been used for somewhat longer than ground-coupled systems, and have been popular since the early 1970s.
One system type not shown in the figure is the standing column system, an alternative type of open loop system. In this system, water is pumped from a well, passed through the heat pump and returned to the same well. These systems have been widely used in New England and were developed for areas in which the well will not produce enough water for a conventional open- loop system. Sometimes a small flow of water must be "Bled" off to waste to keep the well temperature from getting too high or low.