What Is Geothermal Energy?

Geothermal energy is a renewable natural resource that occurs readily beneath the earth's surface.

The word "geothermal" is Greek in origin. "Geo" means earth and "therme" means heat.

This heat is captured as hot water or steam and used to heat and cool homes and buildings or to generate electricity.

Geothermal heating and cooling systems moveheat from place to place rather than produce heat like conventional systems.

The heat is actually produced in the earth's core and rises toward the surface. This earth heat is produced by the slow decay of radioactive particles, a process common in all rock.

Why Geothermal Energy?

While humans inhabit the earth's crust, our primary fuel sources lies beneath it.

Barrel of Oil

Over the past 150 years, humans have consumed all of the easily accessible fuel sources.

Drilling for oil has become more controversial as mankind has to drill deeper to find the precious liquid.

The following concerns have caused people to look for a renewable energy source in place of fossil fuels:

Why Geothermal Energy?

* Fossil fuels produce by-products and waste, polluting the earth.

* Drilling for oil is becoming increasingly difficult as oil reserves lie deeper within the earth's crust. Extracting this oil is more expensive and time consuming.

* This more difficult to reach oil means rising gas prices.



Geothermal Heating And Cooling

Before installing geothermal heating and cooling, a geothermal heat source is needed.

Where do you get that? Right under your feet is the largest storehouse of geothermal energy - the earth!

All you have to do is dig down a few feet (usually about four feet) where the earth's temperature remains at a constant 50-55 degrees year around.

Or, if you're really lucky, you've got a hot spring or a spewing geyser in your backyard!

Geyser

Don't have one of these? Don't worry. There are alternatives.

You will have to install either a closed loop system or an open loop system.

Then you will need a ground source heat pump, also called a geo-exchange system.

Although you may be thinking that you don't understand the concept of a heat pump, or geo-exchange system, there's a heat pump already right in your home. Where? In your refrigerator!

Just put your hand on the back of your refrigerator. Feel the heat? That's the heat pump in action!

The heat pump has pulled the heat from your food inside the refrigerator and transferred it outside. A geothermal heat pump works on the same premise - to transfer heat to and from your home.

Geothermal heat pumps allow not only heating but cooling as well. In the summer, flip a switch to move the heat in the opposite direction - back to the earth.

Open vs. Closed Loop Systems

For the homeowner wanting to increase heating and cooling efficiency,open and closed loop systems must be considered.

Open loop systems are used when groundwater is plentiful. These systems are the easiest to install. Installing an open loop system involves drilling a geothermal well. The water from the well is transferred from the well to the dwelling. It is then disposed of in one of three ways:

*The water is re-injected into the same aquifer via a discharge well.

*The water is allowed to drain on the surface and collect in a pond or lake.

* The water is drained beneath the surface to a designated drainage area.

The amount of water needed for this system depends on the area being heated and cooled. The larger the area, the larger the system. The larger the system, the more water that's needed.

Therefore, the water well and heat pump both need to be large enough to accommodate the customer's needs.

Closed loop systems are, by far, the most common, although they can take several different shapes.

Geothermal Pond Lake Loop System

The Pond/Lake closed loop system must be located near a body of water so that liquid can circulate under the water in a closed pipe system.

Pond/Lake Closed Loop System

Horizontal loop systems are generally the most cost effective if there's enough yard space where trenches are easily dug.

This method requires excavating from three to six feet in the ground and laying 400-600 feet of pipe per ton of heating and cooling capacity required.

Geothermal Horizontal Loop System

Horizontal Loop System

Vertical Closed Loop System

Vertical loop systems are used when yard space is not sufficient. Hole are drilled into the ground to depths of 150-450 feet.

Loops of pipe with a U shape bend at the bottom are placed into the hole. The vertical pipe is then interconnected at the top with an underground horizontal pipe that transfers the water back and forth from the dwelling.

Vertical Closed Loop System

Cost of Geothermal Energy Heating and Cooling Systems

Well, here's the kicker. The moment we've all been waiting for. How much money do geothermal energy heating and cooling systems cost?

Answer: Quite a bit.

The cost of a typical geo exchange system is between $17,000 and $30,000. That's in addition to the costs associated with drilling the well.

However, geothermal heating and cooling systems use 40-70% less energy than traditional systems. Additionally, rather than burning a fuel to produce energy, geothermal heat pumps rely on electricity to transport the heat from the earth into the home or building.

Although some fuel burning devices can be as highly efficient as 95%, geothermal heat pumps can move 4 units of heat to every one unit of heat transported by a fuel-powered device. Thus, geothermal heating and cooling is as much as 400% more efficient.

Depending on the scenario, installing geothermal heating and cooling may be worth the money invested.

Relying on geothermal energy is definitely an alternative to fossil fuels. 

Interested in more information on alternative energy? Please visit these trusted, related sites! 

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Solar Energy for Home  A comprehensive homeowner guide to clean energy generation and to energy saving at home. 

Sunup Solar Power  A one stop source of information for those who want to learn about solar power or for the individual home owner who wants to install a home solar power system.