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Actually, the concept of Green Village Green came to me partly because of geothermal heat pumps. Sounding like a freight train on old rails, our ancient heat and air system was on its last legs, and I wanted to replace it before it died in the heat of summer or the depths of winter. I searched the internet for information and for someone in our hometown to tell me if geothermal would be a viable option for our property. I found plenty on the hows, the whys and the wherefores, but nowhere could I find anyone locally who could do the job. Our local utility company gave me contractors’ names, none of whom offered geothermal. So we went with a high efficiency heat pump. Since then I have come across several nearby companies who offer a number of options, including one business which has installed more than 500 systems. We could even have used our well, avoiding in-ground pipe installation.

The whole subject of heat from the earth is fascinating, particularly if you’ve been to an area of geysers, boiling mud pools and fumaroles. However, it took me a while to understand how the temperature of the earth just below my feet could make my house comfortable. Hope you enjoy the following article.

Till next time,

Carol

Founder and CEO

Green Village Green

Please contact us.

Geothermal Heat Pumps : What are they and will they work for you?

Interest in geothermal or geoexchange heat pumps has been increasing steadily in the past few years and it is no mystery why. Word of the cost savings that are realized when these units are installed is getting around, and many businesses and residences want to get in on the action.

How do geothermal heat pumps work?

While conventional furnaces and boilers burn a fuel to generate heat, geothermal heat pumps use electricity to simply move heat from the earth into buildings, allowing much lower utility use. The most efficient fuel-burning heater can reach efficiencies around 95%, but a geothermal heat pump can move up to 4 units of heat for every unit of electricity needed to power the system, resulting in a practical equivalence of over 400% efficiency.

Underneath the frost line, the ground stays at a constant temperature of about 57 degrees Fahrenheit. That happens to be an extremely efficient operating temperature for heat pumps. Geothermal heat pump systems circulate water between an underground water loop, called an earth heat exchanger, and water-to-air heat pump(s) located throughout a home or large building. The earth heat exchanger is most often a network of high-density polyethylene piping buried in vertical boreholes 150 to 300 feet deep.

The constant temperature of the earth heats or cools the circulating water loop as needed to balance the building’s year-round heating-and-cooling requirements. If your room needs heat, you turn up the thermostat and heat is pumped from the water loop into the room. If your room needs air conditioning, you turn down the thermostat and excess heat is pumped out of the room into the water loop. The system is effective in very hot or cold climates.

Some heat pumps and most geothermal systems also provide domestic hot water at low operating costs.

The only external energy needed for geothermal is the small amount of electricity needed to operate the ground loop pump and fan.

Ground source heat pumps can be installed with closed or open loops in three ways: horizontally, vertically, or in a pond or lake. The type chosen depends on the available land and the soil and rock type at the installation site. Open loop systems operate on the same principle as closed loop systems and can be installed where an adequate supply of suitable water is available and open discharge is feasible.

Heat Pumps

Beginning in the 1970s, air-source heat pumps came into common use. They have the advantage of no combustion, and thus no possibility of indoor pollutants like carbon monoxide. Heat pumps provide central air conditioning as well as heating as a matter of course. Heat pumps operate by moving or transferring heat, rather than creating it. During the summer, a heat pump captures heat from inside a home or business and transfers it to the outdoor air through a condensing unit. During the winter, the process is reversed. Heat is captured from outdoor air, compressed, and released inside.

Much less electricity is used to move heat rather than create it, making heat pumps more economical than resistance heating. However, in all but the most moderate climates, the heating ability of the heat pump is limited by freezing outdoor temperatures. So electric resistance heat is used to supplement outdoor-air-source heat pumps during the coldest weather, preventing "cold blow."

Depending on climate, air-source heat pumps (including their supplementary resistance heat) are about 1.5 to 3 times more efficient than resistance heating alone. Operating efficiency has improved since the 70s, making their operating cost generally competitive with combustion-based systems, depending on local fuel prices. With their outdoor unit subject to weathering, some maintenance should be expected.

More recently the geothermal, ground-source heat pumps, were developed to move or transfer heat like the air-source heat pumps. However, they exchange heat with the earth rather than the outdoor air. Since earth temperature remains relatively constant throughout the year, geoexchange systems operate more efficiently than air-source heat pumps and generally without the use of resistance heat. And because they are working from those constant earth temperatures, there are no blasts of hot air or "cold blow" as with other systems.

Since there is no outdoor unit (as with air-source heat pumps or the central air conditioners used with combustion-based systems), no weather-related maintenance is required.

Although their installation cost is somewhat higher due to the required underground connections for heat transfer to and from the earth, geoexchange systems provide low operating and maintenance cost and greater comfort.

When comparing heating systems, safety, installation cost, operating costs, and maintenance costs must be considered. To simplify the selection process, installation, operating, and maintenance costs can be combined into a life-cycle cost — the cost of ownership over a period of years.

What advantages do geothermal heat pump systems offer?

• A considerable reduction in heating and cooling costs
• Standard, simple controls
• No need for a highly specialized chiller technician or boiler operator
• Highly durable piping (the life expectancy is between 30 and 50 years)
• No high-maintenance, freezing-prone cooling tower
• No boiler to clean or maintain
• No air conditioning equipment on roof to cause leaks
• No harmful chemicals
• No danger of fire, asphyxiation, or explosion from coal, gas, or oil
• Nothing outside to vandalize or steal
• No central system to fail or shut down the entire building.

Commonly Asked Questions about an Uncommonly Sound Technology

What are the major benefits to the home/building owner?

Owners enjoy lower utility bills, lower maintenance, and higher levels of comfort, year-round. They also have the peace of mind of knowing they're being environmentally responsible.

Since a geothermal system burns no fossil fuel to produce heat, it generates far fewer greenhouse gas emissions than a conventional furnace, and completely eliminates a potential source of poisonous carbon monoxide within the home or building. Even factoring in its share of the emissions from the power plant that produces electricity to operate the system, total emissions are far lower than for conventional systems.

What are the environmental advantages?

According to data supplied by the U.S. Department of Energy (DOE) Office of Geothermal Technologies, nearly 40% of all U.S. emissions of carbon dioxide (CO2) are the result of using energy to heat, cool and provide hot water for buildings. This is about the same amount of CO2 contributed by the transportation sector.

A typical 3-ton residential geothermal system produces an average of about one pound less Carbon Dioxide (CO2) per hour of use than a conventional system. To put that in perspective, over an average 20-year lifespan, 100,000 units of nominally sized residential geothermal systems will reduce greenhouse gas emissions by almost 1.1 million metric tons of carbon equivalents.

That would be the equivalent of converting about 58,700 cars to zero-emission vehicles, or planting more than 120,000 acres of trees.

And the waste heat removed from the home's interior during the cooling season can be used to provide virtually free hot water-resulting in a total savings in hot water costs of about 30% annually, and lowering emissions even further.

Is geoexchange used primarily in homes?

While many homes have been fitted with geothermal systems, a large number of commercial enterprises, including factories, retail stores, office buildings, hospitals and schools also use geothermal to save energy and protect the environment. According to the U.S. Environmental Protection Agency (EPA), schools are a particularly attractive place for the use of technology. These schools also save a half-billion pounds of Carbon Dioxide (CO2) emissions per year.

Should all of the nation's schools convert to geothermal, the EPA has estimated that we could reduce oil imports by 61 million barrels annually, and provide the same environmental benefits as planting 8 million acres of trees or converting nearly 4 million cars to zero-emission vehicles.

If the same comparison were made across all commercial and residential segments, the potential for environmental benefit would be staggering.

Does geothermal cost more?

Not necessarily. It depends on how you measure cost. While they often cost more to install in homes than conventional systems because of the ground loop piping, geothermal systems typically have the lowest life-cycle cost of any heating and cooling system. Heating and cooling costs for a typical 2,000-sq.-ft. home can run as low as $1 a day.

Moreover, installation costs have declined substantially in recent years, and they're expected to continue to fall, as more builders and contractors offer geothermal systems, and as the industry develops innovative ways to install the systems faster and more efficiently.

Altogether, geothermal systems are a sound investment. The amount they save the homeowner every month in energy costs is more than enough to offset their higher installation cost. Remember, too, that geothermal means extra savings on repair, maintenance, and hot water bills.

Furthermore, the energy efficiency of the system adds value to the home. The National Association of Realtors relies on the Appraisal Journal to help you determine the total value of your home. An October 1998 article printed in the Journal states that a home's value increases by $10 to $25 for every $1 reduction in utility bills. That's a lot of equity to build just by choosing geothermal!

How much will my system cost to install?

The prices have a wide range based on a number of variables, such as your home or building's size and design, the brand and model you choose, your location, etc., so it is impossible to provide a number here. However, you may be surprised how affordable it is. To find out how much it would cost to add a geothermal system into your home or business, you will need to contact a contractor in your area for an estimate.

How long will it take for my system to pay for itself?

The answer to this question depends on what it would have cost you if you were operating another heating and cooling system, and how much lower your bills will be when you're using the geothermal system. You should ask your contractor to give you an estimated life cycle cost analysis, which should tell you about how much it will cost you to operate the system and how long it will take for the savings to cover the cost of the system completely.

Where can I go to finance a system for my home?

Contact your mortgage broker or local bank to see about using a home equity loan or some other sort of conventional financing means. You might also want to ask your contractor if he/she is able to offer funding through their company or through the manufacturer.

Another option you might consider is obtaining an Energy Efficient Mortgage (EEM) through another lender - click here to read more about EEMs on the ENERGY STAR website.

Are there any financial incentives for installing geothermal?

Some states and utilities have programs to encourage you to install geothermal. Call your state energy office or local utility for more information.

I just bought a home/building with a geothermal system. Who should I call to make sure it's operating properly?

You can look into who installed the system or who serviced it prior to your taking ownership. If you are unable to find that information, you can either call a local contractor or you can call the manufacturer to see whom they have in your area that specializes in your exact system.

I'd like to join the industry and start installing geothermal. How should I go about that?

If you are interested in becoming an accredited installer yourself, contact the International Ground Source Heat Pump Association (IGSHPA) for training courses.

The following sites provided the information in this article:

SouthFace www.southface.org
The International Ground Source Heat Pump Association (IGSHPA) www.igshpa.okstate.edu/geothermal/geothermal.htm
WaterFurnace www.waterfurnace.com
Find a dealer/installer at http://dealers.waterfurnace.com/waterfurnace/
GeoExchange.org http://www.geoexchange.org/