Vertical loop systems

Common in the UK. Where land is limited, vertical installations or a compact Slinky™ horizontal installation can be ideal. If regional soil conditions include extensive hard rock, a vertical installation may be the only available choice. Vertical installations tend to be more expensive due to the increased cost of drilling versus trenching, but since the heat exchanger is buried deeper than with a horizontal system, vertical systems are usually more efficient and can get by with less total pipe.

Horizontal loop systems are not so common in the UK. Horizontal installations are simpler, requiring lower-cost equipment. However, they require longer lengths of pipe due to seasonal variations in soil temperature and moisture content. Since a horizontal heat exchanger is laid out in trenches, a larger area is usually required than for a vertical system.

Open loop systems are not common in the UK. There are two types of Ground Source Heat Pump , closed loop and open loop. In a closed loop system sealed pipes are placed either horizontally or vertically in the ground. Water (with antifreeze) is pumped through the pipes and takes up heat. This is then extracted by the heat pump and released at a higher temperature to drive a space heating system. If the system is used for air conditioning in the summer then it operates in reverse. A typical open loop system abstracts water from an aquifer, extracts the heat in a heat pump and then releases the cooled water back into the aquifer.

Pond or Lake loop systems are not common in the UK. If a home is near a body of surface water, such as a pond or lake, this type of loop design may be the most economical. The fluid circulates through polyethylene piping in a closed system, just as it does in the ground loops. Typically, workers run the pipe to the water, then submerge long sections under water. The pipe may be coiled in a slinky shape to fit more of it into a given amount of space. Pond loops should only be used if the water level never drops below six to eight feet at its lowest level to assure sufficient heat-transfer capability. Pond loops used in a closed system result in no adverse impacts on the aquatic system.