Vertical Geothermal Ground Loop
This is the most common type of closed loop, as it requires the least amount of ground to contain it. However it is the most expensive but most efficient as the earth’s temperature is more consistent with depth.
To install a loop system firstly a vertical bore holes are drilled 150' to 300' deep and at least 15' apart, this gap ensures that the individual loops do not encroach on the available heat energy in the soil.
When the required number of boreholes has been drilled (the contractor will have calculated the number required to suit the buildings heating requisite) U-shaped pipes, typically between 3/4" and 11/4" diameter, are then inserted down into the borehole.
An efficient heat-transferring sealing compound or grout is poured into the gap between the pipe and the soil. This is not only to ensure a good contact between the pipe and the ground, but also to prevent rainwater from penetrating into the borehole.
When all the pipes have been inserted and grouted, they are connected up to an inlet and outlet manifold which supply and return the loop circulating fluid, a mixture of water and antifreeze to and from the heat pump via the circulating pump.
A sketch of a typical vertical loop system follows.