In the purest sense, geothermal systems use solar energy. The earth absorbs an amazing 48% of the sun's energy, leaving a fairly constant underground temperature between 45° and 70° F.
A water solution flows through pipes buried in the ground (ground loop system) absorbing heat from the earth in the winter and moving it to the geothermal system inside the house. Once there, the heat is condensed and transferred to the air that is circulated throughout the home, providing warmth when needed.
In the summer, the process is reversed, absorbing heat from the air inside the home, similar to how a refrigerator extracts heat from food to make it cool, and transfers that heat into the ground through the same loop system.
The heat exchanger, also known as the loop system, captures the stored solar energy in the ground and delivers it back to the geothermal system in the house. There are 4 different types of loops.
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.
This is the most common loop used when adequate land area is available. Loop installers use excavation equipment such as chain trenchers, backhoes and track hoes to dig trenches approximately 6-8 feet deep. Trench lengths range from 100 to 300 feet, depending on the loop design and application.
This loop is used mainly when land area is limited and in retrofit applications of existing homes. A drilling rig is used to bore holes at a depth of 150 to 200 feet. A U-shaped coil of high density pipe is inserted into the bore hole. The holes are then backfilled with a sealing solution.
A pond loop is an option if a large body of water is available within approximately 200 feet of the home. A 1/2 acre, 8 to 10 foot deep body of water is usually adequate to support the average home. The system uses coils of pipe typically 300 to 500 feet in length. The coils are placed in and anchored at the bottom of the body of water.
This system can be installed if an abundant supply of high quality well water is available. A typical home will require 4 to 8 gallons of water per minute. A proper discharge area such as a river, drainage ditch, field tile, stream, pond, or lake must be present. Check your local codes for restrictions before selecting a specific discharge method.
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.