Per the International Ground Source Heat Pump Association (IGSHPA), “Ground source heat pumps (GSHPs) are electrically powered systems that tap the stored energy of the greatest solar collector in existence: the earth. These systems use the earth’s relatively constant temperature to provide heating, cooling, and hot water for homes and commercial buildings.”
Ground source heat pumps are either closed or open loop systems, and can be installed either horizontally, vertically, or in a body of water. The installation depends on extensive research on the amount of land available, and the soil and rock composition of the site.
For closed loop systems, water, food grade glycol, or an antifreeze solution is circulated through plastic pipes buried beneath the earth’s surface. During the winter, the fluid absorbs the heat from the earth, and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and sinking it into the ground. This process creates free hot water in the summer, and delivers substantial hot water savings in the winter.
Open loop systems operate on the same heat absorbing and heat sinking principle as closed loop systems, but can be installed where an adequate supply of suitable water is available and open discharge is feasible.