A geothermal system is a heat exchanger that uses the earth or ground water or both as sources of building heat in the winter and as a "sink" for heat removed from a building in the summer.  The system provides heat by removing it from the earth through a liquid such as ground water or an antifreeze solution, which is upgraded by the heat pump and transferred to indoor air.  The system provides cooling by reversing the process.

Ground Loop  - a system of fluid filled plastic tubes buried in the shallow ground, or place in a body of water, such as a pond, near the building.

 

Heat Pump - removes the heat from the fluid in the plastic tubes, concentrates it, and then transfers it to the building.  The process is reversed for cooling.

 

Air Delivery System - conventional ductwork that is used to distribute the heated or cooled air throughout the building.

 

The GHP takes heat from a warm area and exchanges the heat to a cooler area, and vice versa.  The wonderful benefit of such as system is that it can be used for both heating and cooling.  Which means doing away with the need for separate furnace and air-conditioning units AND for free hot water heating during the summer months.

Geothermal heat pumps use electricity to heat and cool, just like a conventional heat pump.  BUT, unlike a conventional heat pump, the GHP system uses the relatively constant temperature of the Earth as a source of heat in the winter and a repository for heat in the summer.

In the winter, the fluid traveling through the underground (or water) loops of pipes is warmed by the Earth's heat.  The collected heat is removed and concentrated by the heat pump, and distributed through the building's ductwork.

To cool the building in the summer, this process is reversed--- the heat pump removes the heat from the indoor air into the ground loops, where it is transferred to the much cooler ground.  The heat removed from the air during the summer can also be used to produce some of your hot water, or to heat swimming pools, instead of transferring to the ground.

The geothermal system uses renewable energy as a source of energy.  It is nothing more than absorbed solar energy from the sun.  The Earth absorbs about 50% of the sun's that reaches the Earth's surface, therefore, it renews itself constantly.

A geothermal heat pump is four to five times more efficient in fuel conversion than a gas furnace.  One benefit of the "super efficiency" is the longer lifespan of the equipment.  The lifespan of a geothermal unit is estimated to be 22 years by the U.S. Department of Energy.  The most energy-efficient central heat and air and the highest rated HVAC units are by far are the geothermal heating and cooling systems.

Geothermal heat pumps are generally classified as "closed-loop" or "open-loop" systems based on the type of ground loop used.

 

Closed-loop System - these systems circulate a solution of water and antifreeze through a series of sealed loops.  The loops can be installed in the ground horizontally or vertically, or they can be place in a body of water, such as a pond.

 

Open-loop System - these systems circulate water drawn from a ground or surface water source.  Once the heat has been transferred in or out of the water, the water is returned to a well or surface discharge.

 

Among these are a few different ways to install these loop systems.  Vertical, horizontal, pond and & open loop designs.  Let's take a look at these types of designs a little more closely.