What is a Geothermal Heat Pump?

A Geothermal Heat Pump, or GHP, is a system that has the ability to utilize energy and heat of the ground or groundwater to heat and/or cool your home. There are four primary configurations for GSPs: Closed-Loop Horizontal, Closed-Loop Vertical, Pond/Lake Loops, and Open-Loop.

Closed-Loop Horizontal Systems consist of a network of pipes, usually made of polyethylene, that are buried about 4-6 feet underground in a series of trenches. These pipes circulate a refrigerant or antifreeze solution, as the name indicates, this is a closed loop system, therefore, the refrigerant solution never comes in contact with the soil or with the groundwater. The solution is circulated through the actual pump system, which is located in the home. The pump circulates the refrigerant, which extracts heat from the ground surrounding the pipes. This heat is then distributed throughout the home.  This process is reversed for cooling; the warm air is drawn out of the home and distributed into the ground. This configuration is ideal for new construction and it also is generally the most cost-effective configuration available.

 















Closed Loop Vertical Systems consist of a network of underground pipes at depths of 100-400 feet deep at intervals approximately 20 feet apart, the vertical pipes are all connected by a horizontal pipe (manifold).  The process of heat extraction and distribution is the same as the Closed Loop Horizontal system, the only difference between the two is the layout of the pipe systems.  This configuration is ideal for locations where the available land is not suitable for a horizontal system.

Pond/Lake Systems are used when there is an adequate body of water close to the home.  A series of pipes are laid underground and placed approximately 8 feet under the surface (to avoid freezing).  Verification that the water body has all of the necessary requirements to serve as a heat source is required.

Open Loop Systems utilize an existing well (and/or a drilled well) as a source for heat.  However, unlike the closed loop systems, the open loop system uses the water from the well as the heat exchange fluid, instead of a refrigerant or antifreeze. This system often requires two wells, one for extraction and a second for return. This is a practical option given the right groundwater conditions. Groundwater codes and regulations must be taken into consideration with open loop systems.