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Geothermal Systems

Geothermal or Ground Source Heat Pump Systems

Geothermal heat pump systems are one of the most thermally efficient class of heating and cooling methods available today for both commercial and residential installations.  It is also known as a geoexchange heat pump system because they operate by exchanging heat to or from the ground.  Although the initial cost of a geothermal system can be several times that of a conventional air source system, the energy savings can recoup that additional cost in the first 5 to 10 years.  The life of the above ground systems are estimated at 25 years while the ground components are greater than 50 years.

The ground temperature of the earth to a depth of approximately 20 feet is fairly constant and varies little from summer to winter.  Because of this, geothermal systems can easily exchange heat with the earth to provide heating, cooling, or hot water.

There are two types of geothermal systems:  closed-loop and open-loop systems.

  • Closed-Loop Systemsgeothermal
    • These systems circulate an antifreeze/glycol solution through plastic tubing buried in the ground and returns it to a heat exchanger, where the heat from the refrigerant is exchanged or transferred.  The tubing can be buried in a vertical or horizontal configuration, or at the bottom of a pond or lake.

A second type of closed loop system is called Direct Exchange, where copper refrigerant lines are buried in direct contact with the ground.

  • Open-Loop Systems
  • Open –loop systems use well water or pond/lake water to provide the heat transfer rather than the ground. Local regulations and codes must be adhered to and an adequately sized body of clean water must be available.

The efficiency of geothermal heat pump systems are considerably higher than that of air-source heat pumps where the coefficient of performance typically ranges from 3 to 6 (geothermal) vs. 1.75 to 2.5 (air-source).

Contact ATC to discuss these energy efficient options and whether they make sense for your particular application.