Geothermal is derived from Greek, geo means "earth", therme means
"heat". How does geothermal energy work? As its Greek origins suggest,
geothermal energy is heat generated deep within the Earth's core. This
heat can be accessed by digging deep wells and pumping the heated
underground water or steam to the Earth's surface. Once extracted from
the earth, it can be used to generate electricity for heating and
cooling homes or buildings. For the homeowner, geothermal energy can be a wise choice in
alternative energy use. Though the majority of geothermal energy used
today is industrial, it is also available to the homeowner with the
installation of a geothermal heat pump.
How does geothermal energy work when utilized in a residential heat pump? Heat pumps draw their energy source primarily from underground. The most common geothermal system is a closed loop system, where a pipe filled with fluid is buried beneath the ground. In colder climates the fluid used will have antifreeze properties, while in warmer climates, water is often used.
Below six feet, the Earth's temperature remains a constant 50-55 degrees. In winter months, a heat pump absorbs this extra heat and transfers it back into your home. In summer months, the system draws heat from the home and transfers it back into the ground. Efficiency of the heat pump is solely dependent upon the heat transfer between soil and the ground loop. Soil and heat properties can vary immensely, your contractor should consult a geological source pertaining to your specific location.
It should be noted that heat pumps are more efficient in moderate climates where heat transfer does not require excessive energy. In colder climates, where temperatures may fall below freezing, most homeowners will need to consider a backup source, such as gas or electric, for heating on extremely cold days.
The initial expense for installation of a heat pump is higher than conventional systems, but geothermal energy is one of the most cost effective heating/cooling systems for your home. Savings in energy costs will be significant over the years.
In short, depending on your local climate, geothermal energy can provide a safe, clean, cost-effective energy source for your home.