Using the Earth as a heat source/sink a connection is made between the object (building/home/mall/etc), which is to be heated/cooled and the earth. This earth connection begins as piping exiting from the object being heated/cooled and ultimately returns as piping into the object being heated/ cooled.
However it is the path taken by the earth connection between its beginning and its final return that is most important and sophisticated. This middle part of the geothermal earth connection is called a ‘loop.’ Geothermal earth connections may be categorized as “open loop” or “closed loop” systems. Many factors affect the design of this loop section of the earth connection of a geothermal system.

Installation of a closed loop Geothermal system on a project in Dominical Costa Rica