Outdoor air temperatures vary greatly throughout the year while temperatures underground stay fairly constant. The earth absorbs and stores approximately 47% of the sun's solar energy. As a result, the temperature of the earth four to six feet below grade is fairly moderate and stable.
The underground temperature in northern climates is approximately 45° and in southern climates it is in the range of 70° year round. The geothermal system takes advantage of this stored energy by using it to provide the most energy efficient heating and cooling system available.
Rather than generating heat, a geothermal system transfers heat from one place to another. The heat exchanger, commonly referred to as a closed loop system, is buried in the ground and circulates a water solution through a series of pipes. This solution captures the stored solar warmth and delivers it back to the geothermal system located in the house. The geothermal unit then transfers the solar heat throughout the house using standard forced air ductwork or radiant floor heat to deliver comfortable indoor temperatures during the winter.
The same geothermal unit and heat exchanger will reverse this cycle during the cooling season to provide air conditioning. The system removes heat and humidity from the air, transfers and deposits that heat back into the earth through the same loop system.
Your loop system is the heart of geothermal technology. Regardless of the option you select, it will deliver over 500% efficient comfort and savings for many years into the future. Your local geothermal dealer will help you select the proper loop system based on a site survey and by conducting a detailed energy analysis of your home. Installing a geothermal loop system is like getting a 70% discount on energy for the life of your home.
During the heating cycle, the fluid circulates through the loop extracting heat from the ground. The heat energy is transferred to the geothermal unit. The unit compresses the extracted heat to a high temperature and delivers it to your home through a normal duct system or radiant heat system.
For cooling, the process is simply reversed. Because the earth is much cooler than the air temperatures on a hot day, the geothermal system removes heat from the home and deposits it into the ground. The fluid is cooled by the ground temperatures and returned to the unit for cooling your home.