A Wise Investment
The Benefits Speak for Themselves
GeoExchange Heating and Cooling Makes Sense
An Important Renewable Energy Technology
Purchase and Installation
GeoExchange Heat Pump Systems Work!
Comparing Heating Systems
Tens of thousands of homes are being built or retrofitted with GeoExchange heating and
cooling systems every year because of the advantages these systems offer:
superior comfort,
economical operation, noise reduction, and low maintenance. Initially reserved for the
most expensive homes, these systems have become affordable options for thousands of low
and moderate income housing units because of the system's low life cycle costs compared to
all other alternatives in almost every region of the country.
Hundreds of schools from Texas to Canada are now equipped with GeoExchange heating and
cooling systems. In the Midwest, experienced designers find that GeoExchange schools can
cost less to build than other options, even though GeoExchange systems provide full air
conditioning. There are significant savings due to reduced mechanical space needs, since
most systems use unit ventilators installed in the classrooms and offices. In addition,
because the air handling system only provides make-up air and does not carry heat, the
ducts can be smaller, with significant construction savings from reduced floor-to-roof
height requirements. The modular equipment means that, in the event of a malfunctioning
heat pump, the problem is isolated instead of facility-wide. Finally, the tremendous
energy savings that GeoExchange heat pumps offer means more money is available for
education, instead of utility bills.
Benefits are being recognized in the commercial sector, too. One convenience store/gas
station chain is retrofitting one store per week with integrated GeoExchange systems that
use the same earth connection to heat and cool the building, absorb waste heat from
freezers and ice makers, and provide hot water for a car wash area. Not only are the
energy savings substantial, but the costs of water (and sewage charges) associated with
the former water-cooled ice makers are also eliminated.
Integrating a radiant heating system for shop areas with forced air systems for offices
appeals to various types of fabrication shops and garages. The advantages are also evident
in buildings whose owners require user comfort, low cost, and flexibility, such as nursing
homes, hotels, and motels. GeoExchange systems can heat one area of a large building while
they cool another -- increasing efficiency and economy. The popularity of these systems
is
rapidly increasing.
|
|
$ MM BTU |
| Electricity |
$ .07 kwh |
$ 9.06 |
| Propane |
$ .90/gal. (.92 cop)
|
$ 10.85 |
| Natural Gas
|
$ .60/therm |
$ 7.14 |
| Electric Resistance
|
$ .07/kwh |
$ 20.51 |
| GHP (3.5 cop) |
|
$ 5.86 |
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GeoExchange systems are efficient, environmentally-sensitive, comfortable, and
economical. Where the infrastructure has been established, such as the school
market in some regions, installation costs and operating costs are lower than
for alternative systems. Even where the cost of the earth connection increases
first cost, operating savings often provide paybacks of considerably less than
five years -- sometimes less than two years. In addition, electric utility
members of the Geothermal Heat Pump Consortium are so convinced of the value of
this technology for their customers that they often offer design assistance,
referrals, or financial incentives to defray the first cost differential of
GeoExchange systems.
The key
is that GeoExchange heat pumps use electricity to move heat, not to generate it
by burning fuel or using electric resistance elements. Indeed, the U.S. EPA has
found no other technology with more favorable operating efficiencies and
economics than GeoExchange heat and cooling systems.
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In heating mode, GeoExchange heat pumps concentrate heat received from the earth to
warm buildings and heat water. In cooling mode, unwanted heat is discharged by the
systems and dissipated into the earth -- ultimately rejected as heat to the atmosphere
from the earth or recycled back into the building for space or water heating.
The U.S. Environmental Protection Agency has concluded that well-designed and
properly installed high efficiency GeoExchange heat pump systems produce less
environmental harm than any other alternative space conditioning technology currently
available. On a full fuel cycle basis, GeoExchange systems are the most efficient
technology available, with the lowest CO2 emissions for minimum greenhouse warming impact.
Overall, the EPA found GeoExchange heating and cooling systems to have the lowest
environmental cost of all technologies analyzed -- including air-source heat pumps and
natural gas furnaces.
Most GeoExchange heat pumps use a hydrofluorocarbon
(HCFC) refrigerant called R-22 in
the compression cycle. Because R-22 is an HCFC instead of a CFC, it has much lower
stratospheric ozone depletion potential. As is the case for today's refrigerators,
GeoExchange heat pumps use hermetically-sealed compressors, so refrigerant leaks and
recharging are rare. If repairs are needed, mechanics use refrigerant recovery systems
that minimize loss of refrigerant to the atmosphere. Alternative refrigerants are being
developed and are expected to be increasingly compatible with today's equipment.
On the local level, the primary environmental concern is the potential for ground water
contamination. The GHPC supports contractor training, certification, and International
Ground Source Heat Pump Association (IGSHPA) programs to assure that systems are designed,
installed, and operated with complete environmental compatibility.
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As in the case of all major decisions, choosing a GeoExchange heating and cooling
system requires careful consideration to insure that the consumer receives the highest
quality system and installation. The Geothermal Heat Pump Consortium (GHPC) offers the
following guidelines:
Ratings and certification: The Air-Conditioning and Refrigeration Institute (ARI) is a
non-profit organization that certifies performance of residential and small commercial
GeoExchange equipment. For equipment classes rated by ARI, the GHPC suggests that
consumers look for the ARI seal. (ARI does not rate large, commercial GeoExchange
equipment greater than 135,000 Btu/hr).
Warrantees: Manufacturers' terms of warranty vary. To assure a high quality
installation, consumers should seek a performance guarantee on the installed system, as
opposed to coverage limited to the heat pump itself.
Sizing: Numerous studies have shown that heat pumps are often sized too large. For
maximum efficiency, heating and cooling loads should be carefully determined using
accepted procedures such as the Air Conditioning Contractors Association's Manual J. The
actual unit size should be within 15 percent of the calculated load. Heat pumps that are
too large waste energy and do not provide proper humidity control.
Design: Residential system design is straight-forward, but the most satisfactory
results are obtained with experienced contractors. Aspects to consider include careful
duct design and installation in which ducts are kept in conditioned spaces and are
permanently sealed; high quality insulation, glazing, and other envelope features to
minimize loads and reduce air infiltration; and careful matching of heat pump and earth
connection capacity to building load. It may be advantageous to specify two-speed or
variable speed systems where heating requirements are much greater than cooling, to assure
good humidity control. Finally, the contractor should examine ways to use the GeoExchange
system to provide hot water.
Installation: Proper installation is a key to success. The GHPC recommends that
consumers employ experienced contractors who will provide the names of customers with
comparable systems. For larger commercial systems, design professionals should aid in the
selection of qualified bidders to assure quality installations at competitive prices. In
both cases, local utility and manufacturer members of the GHPC may be able to assist. In
addition, many states have Heat Pump Councils which may provide additional referrals.
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