GEOEXCHANGE TECHNOLOGY: WHAT IS IT?



Geoexchange technology uses the earth's renewable energy to heat or cool a home or
other building, and can help to provide hot water.  The systems are sometimes
referred to as geothermal heat pumps, ground source heat pumps, or green heat.  
Regardless of what it is called, the U.S. Environmental Protection Agency (EPA) has
designated  geo-exchange technology as the best choice for "the most energy-
efficient, environ- mentally clean, and cost-effective space conditioning systems
available today."



GEOTHERMAL HEATING AND COOLING SYSTEMS

Geothermal Systems provide heating, cooling, and humidity control, and may also
provide water heating to supplement or replace conventional water heaters.  

Geothermal heating and  cooling systems work by moving heat, rather than by
converting chemical energy to heat as in a furnace.  

Geothermal Heating and Cooling Systems have three major subsystems or parts:

    (1)    a geothermal heat pump;

    (2)    a connection for transferring heat between its fluid and the earth;

and       (3)    a distribution subsystem for delivering heating or cooling to the
             building.       


GEOTHERMAL HEAT PUMPS

Geothermal Heat Pumps are generally packaged in a single cabinet, and include the
compressor, loop-to-refrigerant heat exchanger, and controls.  Systems that distribute
heat using ducted air also contain the air handler, duct fan, filter, refrigerant-to-air
heat exchanger, and condensate removal system for air conditioning.  For home
installations the geothermal heat pump cabinet can be located in the basement,  the
attic or in a closet.  For commercial installations, it may be hung above a suspended
ceiling or installed as a self-contained console.


DISTRIBUTION SUBSYSTEMS

Most residential geothermal systems use conventional ductwork to distribute hot or
cold air  and to provide humidity control, however some systems use water-towater
heat pumps with one or more fan-coil units, baseboard radiators, or under-floor
circulating pipes.  Properly sized, constructed, and sealed ducts are essential to
maintain system efficiency.  Ducts must be well insulated and, whenever possible,
located inside the buildings conditioned space.

Geothermal heating and cooling systems for larger homes or commercial buildings
often use multiple heat pumps, one for each separable area, which are attached to
the same earth connection by a loop inside the building, thus allowing each area to be
individually controlled, thus generally proving to be the most economical.


WATER HEATING
Free Hot Water Generation:

As a bonus, geothermal systems can produce some or all of your hot water at much
higher efficiencies than ordinary methods. A simple connection is made so the
geothermal system can deliver hot water to be stored in your hot water heater. In fact,
the heat removed from your home during the cooling cycle is deposited directly to the
water heater instead of the ground. This provides you with virtually free hot water.

Many residential-sized systems installed today are equipped to provide domestic hot
water when the system is providing heat or air conditioning.  The unit is a small
auxiliary heat exchanger at the compressor outlet.  It transfers excess heat from the
compressed gas to a water line that circulates water to the house's hot water tank.  In
summer, when the air conditioning runs frequently the unit may provide all the hot
water needed by a household.  It can provide four to eight gallons of hot water per ton
of cooling capacity each hour it operates.  It provides less hot water during the winter,
and none during the spring and fall when the system is not operating.   Because the
heat pump is so much more efficient than other means of water heating,
manufacturers are beginning to offer  "triple function," "full condensing," or "full
demand" systems that use a separate heat exchanger to meet all of a household's hot
water needs.  These units cost-effectively provide hot water as quickly as any
competing system.   These 'on demand' systems provide hot water as soon as there is a
demand for it, eliminating the need to heat stored water as conventional hot water
tanks require.


CLOSED AND OPEN LOOP SYSTEMS

Geothermal systems use the earth as a heat source and heat sink.  A series of pipes,
commonly called a 'loop,' carry a fluid used to connect the geothermal system's heat
pump to the earth.   There are two basic types of loops,  closed and open.  

OPEN LOOP SYSTEMS are the simplest, using ground water drawn from an aquifer
through one well, passing it through the heat pump's heat exchanger, and discharging
it to the same aquifer through a second well located some distance from the first.  
However, open loop systems do have associated challenges.  Some local ground water
chemical conditions can lead to fouling the heat pump's heat exchanger.  Such
situations may require precautions to keep carbon dioxide and other gases in solution
in the water, or may necessitate the use of cupronickel heat exchangers and heat
exchangers that can be cleaned without introducing chemicals into the gourndwater.   
Environmental concerns dictate that local officials be consulted to assure compliance
with regulations concerning water use and acceptable water discharge methods.  

CLOSED LOOP SYSTEMS are becoming the most commonly used.  They are economical,
efficient and reliable.    Water, or a water and antifreeze solution, is circulated through
a continuous buried pipe, thus preventing contamination to the external environment.
 When properly installed, closed loop systems are economical, efficient, and reliable.


Effectiveness:

Geothermal systems use small amounts of electricity to transfer heat to and from the
ground to your home. On average, it can produce four units of energy for every unit of
electricity used to power the system. Even the best conventional systems deliver less
than one unit of energy for each unit it consumes. Homeowners typically experience an
annual savings of 30% to 70% when compared to ordinary systems.


System Lifespan:

Ordinary systems require expensive regular maintenance for each unit - the furnace,
the air conditioner, and the water heater. When properly installed, a GeoComfort
geothermal system requires little or no maintenance beyond periodic checks and filter
changes. Equipment life is prolonged since geothermal are located indoors and out of
the varying climate and weather. Geothermal systems typically last more than 20 years
if properly maintained.


Environmentally Friendly:

Geothermal is recognized by the United States Environmental Protection Agency as the
most environmentally-safe, cost effective heating and cooling system on the market.
Installing a geothermal system is equivalent to planting 750 trees or taking 2 cars off
the road.


Comfort:

Geothermal systems heat and cool homes evenly, eliminating the hot and cold blasts of
air found with conventional systems. Geothermal also dehumidifies the air during hot
summer months.


Quiet:

Geothermal systems use the same principles that operate a refrigerator or freezer, and
the units are just as quiet. There is no unsightly outdoor unit to disturb you or your
neighbors.


Clean & Safe:

Geothermal units do not use fossil fuels such as natural gas and propane, thereby
eliminating the dangers of combustion. No more worries about flames, fumes, odors, or
carbon monoxide.
ASD CERTIFIED
     GREEN TREE
     ENVIRONMENTAL SERVICES
GEOTHERMAL, WATER WELLS, AND GEO-TECHNICAL

       Contact Dudley at: (904) 902-0101

             or by email at:   Dudley.greentree@yahoo.com