The principals on which these highly efficient systems operate are surprisingly simple. Geothermal heating and cooling systems, also known as Geo Exchange systems, tap into the constant, moderate temperatures found just a few feet below the surface of the earth, to offer the finest in home comfort conditioning. The word “Geothermal” means pertaining to the heat of the earth, and it’s literally right there in your back yard. Typically, the land surrounding a home or other building contains a vast reservoir of low temperature thermal energy, typically 10 times the amount required over an entire heating season. This resource is constantly re-supplied by the sun and surrounding earth. Highly efficient geothermal systems use a small amount of energy to capture and move a large amount of free energy from the ground. In a typical home, as much as 70% of the total energy bill comes from heating, cooling and hot water production. As a result, the greatest opportunity to reduce your energy cost is to improve the efficiency of your heating, cooling and hot water system by utilizing this “down to earth” technology. Best of all, this energy source is free, renewable, clean and environmentally friendly.
A geothermal system captures this free energy from the earth by using a series of pipes (or earth loop) buried in the ground, whereas the more common air source heat pumps extract and dissipate heat from the air. What makes a geothermal system more efficient than a conventional air source system is that the heat source (the ground) maintains a constant temperature year round, whereas the air temperature in this area can fluctuate as much as 80+ degrees during the year. Put more simply, in the heating mode it is easier for a geothermal system to extract heat from a 50 degree earth loop system than it is for an air source system to extract the same amount of heat from 20 – 30 degree outdoor air.
Earth loops, which are the heart of a geothermal system come in 2 basic types. Closed loop systems are made of durable high-density polyethylene pipe, which are buried in the earth. These systems transfer heat by circulating a solution of water and environmentally safe antifreeze. Open loops use ground water which is pumped directly from a well, as a heat source. Typically, in the Northern Neck and Middle Peninsula, the preferred type is a closed vertical loop system (although there are several other configuration methods). Installing vertical loops require the use of a well drilling rig. Multiple holes are bored vertically about 10 feet apart. A double pipe is inserted into each hole and then backfilled with soil and grout to seal the hole. The vertical pipes are then connected to a horizontal manifold system, filled with a solution of anti-freeze and water and then routed to the geothermal unit located inside the home.
During the heating mode, a special fluid circulates through the pipe where heat energy is transferred from the ground to the fluid and then to the geothermal unit located in the home, providing warm comfort to the structure. Inside the home, the heat can be distributed through either a conventional duct system or a hydronic radiant system.
To provide air conditioning, the process simply reverses. Heat is removed from the home and transferred to the loop fluid. As the warm fluid travels through the pipe in the earth, it is cooled. In the cooling mode, the earth serves as a “heat sink,” a place to deposit the heat removed from the home.
As a bonus, a geothermal unit can provide some or all of your hot water at higher efficiencies than that of a standard electric tank water heater which can offer additional energy savings. Using a simple connection to your water heater, the geothermal unit will deliver hot water to the tank during the heating and cooling modes. In fact, the heat removed from your home during cooling is deposited directly into your water heater providing you with virtually free hot water,
as it is produced as a by product of cooling your home.
According to an EPA study titled “Space Conditioning, The Next Frontier” (Report 430-R-93-004), the Department of Energy and the EPA recognized geothermal systems as the most environmentally, cost-effective and energy efficient heating and cooling technology available. So you can make a significant contribution to a cleaner environment—while saving substantially on your home’s energy bills. To put this into perspective, recent industry estimates indicate that every 100,000 homes with geothermal systems reduce foreign oil consumption by 2.15 million barrels annually and reduce electricity consumption by 799 million kilowatt hours annually.
A geothermal system can be easily installed in most homes—new or old, large or small. With many sizes, configurations and options available, the system will be designed and installed to provide the homeowner with many years of reduced energy costs, enhanced comfort, safety and reliability—all from a technology that’s proven, efficient, available, and environmentally friendly.
An investment in a geothermal system for heating and cooling your home provides an array of benefits that can be hard to find with other systems. For example:
Lower Operating Cost
A geothermal system operates more efficiently than conventional systems because they are able to produce more units of energy (heat or cool) per unit of electricity used. By combining stored earth energy with safe electrical power, homeowners can expect to achieve substantial savings on energy bills.
Geothermal systems can provide precise distribution of comfortable air all year long. During heating you will experience warm air without the hot and cold blasts normally associated with furnaces or older air source heat pumps.
Because propane, natural gas, or oil is not required to operate a geothermal system, there are no combustion flames, or carbon monoxide production.
With the all electric geothermal system, there are no fumes or soot produced during operation which can translate to lower maintenance costs.
Unlike ordinary air conditioners or heat pumps there is no outdoor unit. Geothermal units are designed for very quiet operation, similar to your refrigerator.
Unlike ordinary air conditioners or heat pumps, geothermal units are installed indoors, so they are not subject to the wear and tear caused by rain, ice, snow, debris, or vandalism.
Because there is no combustion, geothermal systems do not emit carbon dioxide, carbon monoxide or other greenhouse gasses. Furthermore, most geothermal systems utilize the environmentally friendly non-CFC refrigerant R-410a.
As you can see, geothermal systems offer a wealth of benefits. When properly installed in your home by a qualified, trained and experienced heating and air conditioning contractor, a geothermal system will provide years of efficient, comfortable and environmentally friendly operation for you and your family. If you are considering building or purchasing a home in the area, or replacing the existing central heating and air conditioning system in your home do yourself the favor of exploring the features and benefits of a geothermal system.