Geothermal Energy for a Residential Heat Pump
Using Alternative Energy to Heat or Cool Efficiently and Save Money
Aug 12, 2009
Geothermal energy is literally heat from within the Earth. Famous examples of this tremendous supply of energy include Old Faithful geyser in Yellowstone National Park and the hot springs of Arkansas and South Dakota.
History of Geothermal Energy
The history of humans harnessing geothermal energy can be traced back to the American Paleo-Indians using hot springs for heat and bathing 10,000 years ago. The first geothermal power plant was put into service in the early 20th century.
Since the early 1940s, geothermal heat pumps (GHPs) have been used for residential heating. According to the US Department of Energy, GHPs are the most efficient heating and cooling system currently available.
Closed Loop Geothermal Technology
The technology behind heat pumps is relatively well known, if applied in a different manner. To harness the Earth's energy, a long closed loop of tubing (usually) is buried below the frost line in the residence's yard. Over a mile of tubing can be buried depending on the size and energy requirements of the home. The same technology is used in refrigerators.
The temperature is nearly constant just a few feet below the surface of the Earth, ranging between 45 and 75 degrees Fahrenheit. In the winter, the ground is warmer than air while in summer the ground temperature is cooler than air. Using a liquid filled loop as a heat exchanger instead of outside air is much more efficient.
Environmentally friendly fluid is pumped through the ground heat exchanger to pick up heat in the winter. This heat is used in conjunction with an air handler or in-floor heating to heat the home. In the summer, the process is reversed for cooling.
Geothermal Heating and Cooling Saves Money
While a GHP can cost nearly twice as much as a typical heating and cooling system, it can pay for itself with energy savings in as little as 2 years. Of course, to achieve these savings, professional design and installation are necessary. The complicated thermodynamics require system engineering to correctly size pumps, loops and air handling equipment.
Helping to offset initial cost are federal and state tax incentives. Purchasing Energy Star certified components ensure optimal system performance and savings. Coupling geothermal energy with either wind or solar energy systems can lead to increased residential efficiency and energy independence.
Experts agree that geothermal energy has a place in the world energy portfolio. To keep up with increasing energy demands, GHPs and other green energy systems should be considered in all new construction. With a little up front investment, the economic and environmental benefits realized by future generations could be incalculable.
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