Closed-loop systems are becoming most common. There are 5 types of closed loop systems. All types use a continuous loop where the heat transfer fluid is circulated.  A horizontal loop is usually the most cost effective when adequate yard space is available and trenches are easy to dig. Using trenchers or backhoes digging trenches three to six feet below the ground, you then lay a series of parallel plastic pipes. The trench is then back filled, taking care not to allow sharp rocks or debris to damage the pipe. A typical horizontal loop will have 400-600 feet of pipe per ton of heating and cooling capacity.

Vertical loops are preferred in many installations where yard space is insufficient and where preservation of existing landscaping is desirable. Contractors bore vertical holes in the ground 150-450 feet deep. Each hole contains a single loop of pipe with a U-bend at the bottom. The hole is then backfilled or grouted to improve the thermal conductivity. Each vertical pipe is then connected to a horizontal pipe underground to and from the heat pump. Vertical loops are generally more expensive to install, but require less piping than horizontal loops.

Slinky loops are used to reduce the heat exchanger per foot trench requirements but require more pipe per ton of capacity. This pipe is coiled like a slinky, overlapped and laid in a trench. Two-pipe systems may require 200-300 feet of more pipe per ton of nominal heat exchange capacity. The trench length decreases as the number of pipes in the trench increases or as slinky overlap increases.

Pond loops are a special kind of closed loop system. Where there is a pond or stream that is deep enough and with enough flow, closed loop coils can be placed on the bottom. Geothermal transfer fluid is pumped just as a closed loop ground system. First cost economics are very attractive and there is no aquatic environmental impact.

Geothermal heating and cooling systems can be connected to the earth in a variety of ways. High system performance is dependent upon good installation practices. ECONAR’s highly trained authorized dealers are professionals who understand local codes and conditions. Visit our where to buy area and you’ll find an ECONAR authorized dealer who can discuss the best system for you.