Geothermal energy is one of the most efficient forms of renewable energy, and can be effectively used for heating and air conditioning of a single family home, as well as large apartment and office buildings.
A Geothermal heating and cooling system will work day and night, in the summer and in the winter. It does not need sun or wind to operate, and the efficiency of a geothermal system is much higher than solar panels. All you need to operate a geothermal system is a relatively small amount of electricity to operate a water pump and a fan.
How geothermal heating and cooling works
A geothermal heat system uses a geothermal heat pump and a ground source heat exchanger to extract the earth’s thermal energy and combine it with thermal energy produced by the heat pump itself, to increase efficiency. The ground temperature below the freeze zone (about 6 feet below ground) is constant, at about 55-60 degrees Fahrenheit, which means in the summer it is way below the ambient temperature, and in the winter its way above the outside temperature. By combining geothermal energy with the thermal energy produced by the geothermal heat pump, you achieve the efficiency of about 3 times more than a conventional heating or cooling system.
In a nutshell, here is the very basic setup of such a system: A ground source heat exchanger is buried into the ground – either as loops in a trench of 6-9 feet deep, or into a bore hole or a well of 300-500 feet deep. A heat exchanger can also be placed in a large enough body of water, but this and other setups are not as common, so we will skip them for now.
The water pump circulates the heat exchange liquid (a form of antifreeze) through the ground source heat exchanger loops, bringing the geothermal energy to the heat exchanger inside a geothermal heat pump. Meanwhile, a heat pump (which essentially works as an Air Conditioner, but in forward and reverse modes) produces the needed hot or cold air, which is combined in the heat exchanger with the earth’s thermal energy, and then delivered through air ducts to your living room or bedroom.
How the heat pump works
The video above demonstrates the the basic principal of heat pump operation, which is essentially a dual mode air conditioner.
The heat pump operates in the following way: when the gas is compressed, it releases heat, and when it is decompressed, it releases cold.