A geothermal heat pump uses the earth to heat and cool a house. There are two types of geothermal heat pump systems. One type of system is direct exchange. These systems, also known as a single loop, consist of a refrigerant in a copper tube. The coolant leaves the heat pump, goes out of the house, and under the ground where it exchanges heat with the ground then returns to the heat pump. These systems are gaining popularity due to their efficiency and low operating cost.
The other type of geothermal heat pump is a double loop. In this system, the refrigerant loop exchanges heat with a secondary loop made of plastic pipe filled with antifreeze fluid. The plastic pipe leaves the house and exchanges heat with the ground.
There are three basic components to a geothermal system. They are the length of buried tubing, a liquid pump pack, and a water source heat pump. The buried tubing (which is usually 400-600 feet) is where the heat exchange occurs between the earth and the enclosed heat transfer fluid. The number of loops that you need will depend on the size of your house: 3 to 5 loops is not uncommon.
The next component is a liquid pump. This is what pumps the heat transfer fluid through the system.
The last piece of the system is the heat pump. This water source heat pump is what replaces your standard boiler or furnace.
There are different types of heat pumps. Water-to-air heat pumps are designed to replace forced hot air systems. In addition to providing heat in the winter, they work as a central air conditioner in the summer.
The next type of system is water-to-water. This heat pump is used to provide heat in structures that use hot water as the heating medium. This would include baseboard radiators and radiant floor heating systems. The biggest drawback with this system is that it is not capable of providing air conditioning during the hot summer months.
Finally, there is a hybrid heat pump system. This pump is capable of producing forced air heat and hot water. These systems are used in houses that have combination heating systems. A typical example would be a house that might have a radiant floor heating system in the garage or basement, but also has a forced hot air system for the rest of the house.
Geothermal heating is gaining in popularity, and for good reason. Rising energy costs and advanced in technology are the primary reasons. A typical homeowner can expect to save between 30% and 70% on utility costs if they size and install their system properly.
Geothermal heat also provides homeowners with independence from the volatile and rising cost of oil and gas.