Geothermal Energy - Earth's Heating and Cooling

From the terms 'geo' (Earth) and 'thermal' (heat), geothermal energy is literally heat that is derived from the Earth itself. The source of this heat is thought to be radioactive decay occuring deep within our planet's crust, filtering heat up through fissures and fractures within the rock. Geothermal heating methods have been in use since ancient Roman times, and still exist widely in parts of the world today.

Geothermal Energy is Derived from the Earth

Modern geothermal systems take advantage of the ground a few feet beneath the Earth's surface to offer both heating and cooling for a home. Since the ground remains a fairly stable temperature year round, it can be used to draw heat during the winter months and exchange that heat for cold during the summer. Geothermal energy has the fantastic advantage of being green, clean, and totally renewable.

In a geothermal exchange system, a refrigerant liquid is pumped through tubing or pipes in the ground, heating the liquid on its way back into the home. Heat is drawn or 'exchanged' from the system and used to suppliment existing home heating furnace and boiler equipment. The same thing happens in warmer months, but in reverse. Because the ground is now very much cooler, the liquid exchanges the heat back into the Earth and returns to the home for use in air conditioning and refrigeration systems.

Energy Saving Tips - Geothermal Heating EPA Studies have shown that a geothermal exchange system could save between 30-40% of home heating costs and 20-50% of cooling costs simply by using clean, green, natural heat from the Earth!

Geothermal Heat Exchange Systems - Costs vs. Benefits

In the past, geothermal heat pumps and exchange systems had the stigma of being costly and cumbersome. Recent advances however, in both technology and insulation techniques, have seen these costs decline steadily over the past several years. As it becomes a more popular and widespread method of home heating and air conditioning, the pricing of geothermal equipment resources continues to drop. The systems, once installed, add extremely high-level resale value to a home and are built to last for several decades.


Geothermal Heat Pumps - How They Work For Both Heating and Cooling

Geothermal Closed Loop System

Depending upon the time of year, a geothermal heat pump can work to either heat or air condition a home or structure by using the fairly constant temperature of the Earth a few feet beneath the ground. During winter months the ground temperature is warmer, so by pumping refrigerant through a series of looped circuits, the liquid is heated and brought back to the home. In summer months the reverse is true, as the ground is generally cooler than the air above the surface. The same liquid now transfers it's heat into the cooler soil, sending a much cooler refrigerant back into the home. This type of closed loop system can be either horizontal or vertical, meaning the loops can lay in the Earth in a shallow horizontal pattern, or can be sunk deep into the ground in an elongated vertical method. Either way, a fan and heat exchange unit can then utilize the hot or cool air for heating or air conditioning accordingly. Geothermal energy returning to the home can also be utilized to provide hot water.

Geothermal Open Loop System

Open loop geothermal heat systems work slightly differently by drawing well water for use as the heat source (or heat sink). After the heat exchange takes place, the water is returned to the well to once again be naturally heated or cooled by the Earth. Geothermal loops can also be submerged in a natural pond or lake.

The US Environmental Protection Agency (EPA) now includes geothermal heat pumps among the equipment that it rates within the Energy Star® program. Up to 70% of the energy derived from these pump systems is pure green renewable ground energy. Although intially more costly when compared to conventional heating and cooling systems, the savings offered through using geothermal energy equipment eventually offsets the initial investment. US Government granted energy rebates may be available for the installation of certain geothermal heat pump systems. Some utility companies offer lower seasonal rates for customers using geothermal pumps as well.

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