Geothermal System Components

Ground Loop

• The ground loop component of a geothermal system consists of a series of polyethylene pipes buried in the ground near your home. The pipes contain a liquid called a transfer fluid. This fluid absorbs heat from the house and sends it into the ground to keep your home cool. When heating is necessary, the fluid absorbs heat from the ground and carries it to the home. There are a number of ground loop configurations, each dependent upon factors, such as the size of your home and property, the amount of heat loss experienced by the home, nearby groundwater availability and other factors. Horizontal closed loop systems are suitable if your property area is greater than one acre and are placed horizontally 6-to-10 feet below the surface. A vertical closed loop design is favorable if you have limited property space. These pipes are buried vertically approximately 20 feet underground. Because ground temperatures at a depth of 20 feet are more consistent compared to shallower depths, a smaller amount of piping is need for this configuration. Other types of ground loop designs use well water to transfer heat in an open loop configuration, or have a closed loop pipe system submerged underwater in a pond or lake.

Heat Pump

• The heat pump section of a geothermal system is where heat energy is exchanged with the ground to either heat or cool your home. The ground loop system runs through the inside of the heat pump. The heat pump takes advantage of the fact that heated air naturally flows from areas of higher temperatures to areas of lower temperatures. In heating mode, fluid warmed from underground flows through the heat pump. A fan blows across the pipe warmed by the fluid. Because the fluid is much warmer than the air inside the heat pump, heat energy is released into the cooler air. The cool air is warmed and distributed throughout your home. To cool your home, the process is reversed. Cool fluid in the pipe absorbs heat from the warm air found inside the home. Once pumped underground, the excess heat in the fluid is absorbed by the cooler earth.

Circulation System

• Many geothermal systems use a fan to force air from the heat pump through a home's ductwork. However, some units use a water method, called a hydronic system. This type of circulation system uses water to absorb heat from the heat pump, where it is then distributed throughout the home. A common method of distributing heat this way is by using heated radiant floors. In some cases, both a forced air and hydronic system is utilized together. When cooling is necessary, the circulation process absorbs heat from inside the home and distributes it to the heat pump.

Additional Advantage

• Geothermal systems are often designed to use excess heat absorbed from the home in the summer to heat hot water at no additional cost to the homeowner. During the heating season, excess heat absorbed from underground is used to provide hot water.