How Geothermal Works
Geothermal heating and cooling systems are the most efficient and environmentally friendly systems on the market today. These systems work differently than conventional systems by taking advantage of the sun’s solar energy that is absorbed and stored by the earth. Below is a great 2 minute video produced by NYSERDA; How It Works: Ground Source Heat Pumps
The Heart of the System: Geothermal Earth Loops
A vertical loop is used mainly when land area is limited, bedrock is close to grade, or in many retrofit applications of existing homes. A drilling rig is used to bore holes to a depth of 150 to 450 feet. A long U-shaped coil of geothermal HDPE pipe is inserted into the bore holes. The holes are then grouted to help with thermal conductivity and to prevent mixing of aquifers.
A pond loop is an option if a large body of water is available within approximately 100 feet of the home. A minimum of 1/2 acre of surface area and a 10 to 12 foot deep pond or lake is usually adequate to support the average home. The system uses a series of geothermal HDPE pipe coils typically 300 to 500 feet in length. The coils are placed in and anchored at the bottom of the pond or lake.