Your
own backyard has the potential to be your source of heating and
cooling comfort. Now you can get safe, reliable, energy efficient
heating and cooling from one piece of equipment. Geothermal energy
represents the leading edge of heating and cooling technology.
It moves heat energy to and from the earth to heat and cool your
indoor environment. And compared to ordinary systems, geothermal
technology can save you 30% to 60% on your monthly energy bills.
Geothermal is the safest, cleanest, most reliable space conditioning
system you can buy.
Geothermal
energy is an unlimited resource. The lot surrounding a suburban
home or other building contains a vast reservoir of low temperature
thermal energy, typically 10 times that required over an entire
heating season. This resource is constantly resupplied by the
sun, the surrounding earth, and heat rejected while cooling during
the summer. The universal definition of geothermal is "...pertaining
to the heat of the earth." By using the earth to provide
up to 50% of a building's total heating and cooling needs, GHP
systems are truly geothermal energy made practical.
Four
basic types of geothermal energy sources:
Closed
loop systems circulate a water-based solution through a "loop"
of small diameter, underground pipes. In cold weather this solution
absorbs heat from the earth and carries it to the geothermal unit.
The geothermal system amplifies the heat and delivers it indoors.
In warm weather the process is reversed, excess heat is carried
from indoors and into the earth. You keep refreshingly cool during
the hottest summer.
Horizontal
loops are often considered when adequate land surface is available.
Pipes are placed in trenches, in lengths that range from 100 to
400 feet.
Vertical
loops are the ideal choice when available land surface is limited.
Drilling equipment is used to bore small-diameter holes from 75
to 300 feet deep.
Pond
(lake) loops are very economical to install when a body of water
is available, because excavation costs are virtually eliminated.
Coils of pipe are simply placed on the bottom of the pond or lake.
Open
loop systems utilize ground water as a direct energy source. In
ideal conditions, an open loop application can be the most economical
type of geothermal system.
Four
times the efficiency.
A
geothermal system uses the Earth's thermal properties in conjunction
with electricity to provide unprecedented efficiency. For every
unit of electricity the system uses, it provides four units of
heating energy, giving a geothermal system a 400% efficiency rating
on average. These numbers can translate into real savings on your
utility bills year- round.
How
does a geothermal system work?
Throughout the year, outdoor temperatures fluctuate with
the changing seasons. However, underground temperatures do not.
In fact, about four to six feet below the earth's surface, temperatures
remain relatively constant year-round. A geothermal system, which
consists of an indoor unit and a buried earth loop, capitalizes
on these constant temperatures.
In the winter, fluid circulating through the system's earth loop
absorbs stored heat and carries it indoors. The indoor unit compresses
the heat to a higher temperature and distributes it throughout
the building. In the summer, the system reverses, pulling heat
from the building, carrying through the earth loop and depositing
it in the cooler earth.
What
makes a geothermal system different from conventional systems?
A geothermal system utilizes the energy from the sun,
which is stored in the earth, to heat and cool homes and buildings.
Typically, electric power is used only to operate the unit's fan,
compressor and pump. So, unlike conventional systems, geothermal
systems do not burn fossil fuel to generate heat--they simply
transfer heat to and from the earth.
How
efficient is a geothermal system?
A geothermal system is more than three times as efficient
as the most efficient conventional system. Because geothermal
systems do not burn combustible fuel to make heat, they provide
three to four units of energy for every one unit used to power
the system.
What
does geothermal mean to the environment?
Because geothermal systems work with nature, not against
it, they minimize the threats of acid rain, air pollution and
the greenhouse effect. An environmentally friendly fluid is used
in the closed, continuous loop.
Do
geothermal systems require much maintenance?
No. In fact, geothermal systems are practically maintenance
free. When installed properly, the buried loop will last for generations.
And the other half of the operation--the unit's fan, compressor
and pump--is housed indoors, protected from the harsh weather
conditions. Usually, periodic checks and filter changes are the
only required maintenance.
Is
the efficiency rating actual or just a manufacturer's average?
All types of heating and cooling systems have a rated
efficiency. Fossil fuel furnaces have a percentage efficiency
rating. Natural gas, propane and fuel oil furnaces have efficiency
ratings based on laboratory conditions. To get an accurate installed
efficiency rating, factors such as flue gas heat losses, cycling
losses caused by oversizing, blower fan electrical usage, etc.,
must be included.
Geothermal heat pumps, as well as all other types of heat pumps,
have efficiencies rated according to their coefficient of performance
or COP. It's a scientific way of determining how much energy the
system produces versus how much it uses.
Most geothermal heat pump systems have COPs of 2.5 - 3.5. That
means for every one unit of energy used to power the system, two
and one-half to three and one-half units are supplied as heat.
Where a fossil fuel furnace may be 50-90 percent efficient, a
geothermal heat pump is about 300 percent efficient. Some geothermal
heat pump manufacturers and electric utilities use computers to
accurately determine the operating efficiency of a system for
your home or building.
How
long is the payback period for a geothermal heat pump system?
To figure this accurately, you must know how much per
year you'll save in energy costs with a geothermal system and
the difference in costs between it and the alternative heating
system and central air conditioner. To calculate your return on
investment (payback in number of years), divide the annual savings
into the additional cost. Keep in mind that energy savings is
only one of the many benefits you receive from a geothermal system.
If
a home has ceiling cable heat or baseboard heat, do air ducts
need to be installed?
Not always. It may be desirable to install geothermal
heat pump room units. For some small homes, one room unit would
provide most of the heating and cooling needs. Ceiling cable or
baseboard units could then be used for supplemental heat.
What
is a geothermal heat pump?
A geothermal heat pump is an electrically-powered device
that uses the natural heat storage ability of the earth and/or
the earth's groundwater to heat and cool your home or business.
How
does it work?
Like any type of heat pump, it simply moves heat energy
from one place to another. Your refrigerator works using the same
scientific principle. By using the refrigeration process, geothermal
heat pumps remove heat energy stored in the earth and/or the earth's
groundwater and transfer it indoors.
How
is heat transferred between the earth and the home or building?
The earth has the ability to absorb and store heat energy.
To use that stored energy, heat is extracted from the earth through
a liquid medium (groundwater or an anti-freeze solution) and is
pumped to the heat pump or heat exchanger. There, the heat is
used to heat the air. In summer, the process is reversed and indoor
heat is extracted from indoors and transferred to the earth through
the liquid.
Does
it do both heating and cooling?
One of the things that makes a heat pump so versatile
is its ability to be a heating and cooling system in one. You
can change from one mode to another with a simple flick of a switch
on your indoor thermostat. In the cooling mode, a geothermal heat
pump takes heat from indoors and transfers it to the cooler earth
through either groundwater or an underground loop system.
Do
I need separate ground loops for heating and cooling?
No. The same loop works for both. All that happens when
changing from heating to cooling, or vice versa, is that the flow
of heat is reversed.
What
types of loops are available?
There are two main types: open and closed.
Does
the underground pipe system really work?
The buried pipe, or "ground loop," is the most
recent technical advancement in heat pump technology. The idea
to bury pipe in the ground to gather heat energy began in the
1940s. It's only been in the last few years that new heat pump
designs and improved pipe materials have been combined to make
geothermal heat pumps the most efficient heating and cooling systems
available.
What
is a closed-loop system?
The term "closed-loop" is used to describe a
geothermal heat pump system that uses a continuous loop of special
buried plastic pipe as a heat exchanger. The pipe is connected
to the indoor heat pump to form a sealed, underground loop through
which an antifreeze solution is circulated. Unlike an open-loop
system that consumes water from a well, a closed-loop system recirculates
its heat-transferring solution in pressurized pipe.
Where
can this loop be located?
That depends on land availability and terrain. Most closed-loops
are trenched horizontally in yards adjacent to the building. But
any area near a home or business with appropriate soil conditions
and adequate square footage will work.
How
deep and long will my trenches be?
Trenches are normally four to six feet deep and up to
400 feet long, depending on how many pipes are in a trench. One
of the advantages of a horizontal loop system is being able to
lay the trenches according to the shape of the land. As a rule
of thumb, 500-600 feet of pipe is required per ton of system capacity.
A well-insulated 2,000 square-foot home would need about a three-ton
system with 1,500 - 1,800 feet of pipe.
How
many pipes are in a trench?
Normally, a run of pipe is laid at five feet then looped
back over itself at three feet once the bottom pipe is covered
with soil. This allows more length of pipe to be put in one trench
and has no adverse affect on system efficiency. Other loop designs
use four or six pipes and allow for shorter trenches if land area
is limited.
What
if I don't have enough room for a horizontal loop?
Closed-loop systems can also be vertical. Holes are bored
to about 125-150 feet per ton of heat pump capacity. U-shaped
loops of pipe are inserted in the holes. The holes are then backfilled
with a sealing solution.
How
long will the loop pipe last?
Closed-loop systems should only be installed using high
density polyethylene or polybutylene pipe. Properly installed,
these pipes will last for many decades. They are inert to chemicals
normally found in soil and have good heat conducting properties.
PVC pipe should not be used under any circumstances.
How
are the pipe sections of the loop joined?
The only acceptable method to connect pipe sections is
by thermal fusion. Pipe connections are heated and fused together
to form a joint stronger than the original pipe. Mechanical joining
of pipe for an earth loop is never an accepted practice. The use
of barbed fittings, clamps, and glue joints is certain to result
in loop failure due to leaks.
Will
an earth loop affect my lawn or landscape?
No. Research has proven that loops have no adverse effect
on grass, trees, or shrubs. Most horizontal loop installations
use trenches about six inches wide. This, of course, will leave
temporary bare areas that can be restored with grass seed or sod.
Vertical loops require little space and result in minimal lawn
damage.
Can
I reclaim heat from my septic system disposal field?
No. An earth loop will reach temperatures below freezing
during extreme conditions and may freeze your septic system. Such
usage is banned in many areas.
Can
I install an earth loop myself?
It's not recommended. In addition to thermal fusion of
the pipe, good earth-to-coil contact is very important for successful
loop operation. Nonprofessional installations may result in less
than optimum system performance.
I
have a pond nearby. Can I put a loop in it?
Yes, if it's deep enough and large enough. A minimum of
six feet in depth at its lowest level during the year is needed
for a pond to be considered. The amount of surface area required
depends on the heating and cooling load of the structure.
What
is an open-loop system?
The term "open-loop" is commonly used to describe
a geothermal heat pump system that uses groundwater from a conventional
well as a heat source. The groundwater is pumped into the heat
pump unit where heat is extracted, then the water is disposed
of in an appropriate manner. Since groundwater is a relatively
constant temperature year-round, it is an excellent heat source.
What
do I do with the discharge water?
There are a number of ways to dispose of water after it
has passed through the heat pump. The open discharge method is
the easiest and least expensive. Open discharge simply involves
releasing the water into a stream, river, lake, pond, ditch, or
drainage tile. Obviously, one of these alternatives must be readily
available and must possess the capacity to accept the amount of
water used by the heat pump before open discharge is feasible.
A second means of water discharge is the return well. A return
well is a second well bore that returns the water to the ground
aquifer. A return well must have enough capacity to dispose of
the water passed through the heat pump. A new return well should
be installed by a qualified well driller. Likewise, a professional
should test the capacity of an existing well before it is used
as a return.
How
much groundwater does an open-loop system need?
Geothermal heat pumps used in open-loop systems need differing
amounts of water depending on the size of the unit and the manufacturer's
specifications. The water requirement of a specific model is usually
expressed in gallons per minute (g.p.m.) and is listed in the
specifications for that unit. Generally, the average system will
use 1.5 g.p.m. per ton of capacity while operating.
Your well and pump combination should be large enough to supply
the water needed by the heat pump in addition to your domestic
water requirements. You will probably need to enlarge your pressure
tank or modify your plumbing to supply adequate water to the heat
pump.
What
problems can be caused by poor water quality?
Poor water quality can cause serious problems in open-loop
systems. Your water should be tested for hardness, acidity and
iron content before a heat pump is installed. Mineral deposits
can build up inside the heat pump's heat exchanger. Sometimes
a periodic cleaning with a mild acid solution is all that's needed
to remove the buildup.
Impurities, particularly iron, can eventually clog a return well.
If your water has a high iron content you, should be sure that
the discharge water is not aerated before it's injected into a
return well.
Finally, you should opt against using water from a spring, pond,
lake or river as a source for your heat pump system unless it's
proven to be free of excessive particles and organic matter. They
can clog a heat pump system and make it inoperable in a short
time.
Does
an open-loop system cause environmental damage?
No. They are pollution free. The heat pump merely removes
or adds heat to the water. No pollutants are added whatsoever.
The only change in the water returned to the environment is a
slight increase or decrease in temperature.
Some people are concerned that open-loop systems contribute to
the depletion of our ground water resources. This issue is not
critical in some parts of North America because of abundant supplies
of ground water.
Are
there any laws that apply to open-loop installations?
In some localities, all or parts of the installation may
be subject to local ordinances, codes, covenants or licensing
requirements.
What
are the components of a geothermal heat-pump system?
The three main parts are the heat-pump unit, the liquid
heat-exchange medium (open or closed loop), and the air-delivery
system (ductwork).
Are
all geothermal heat pumps alike?
No. There are different kinds of geothermal heat pumps
designed for specific applications. Many geothermal heat pumps,
for example, are intended for use only with higher temperature
ground water encountered in open-loop systems. Others will operate
at entering water temperatures as low as 25°F which are possible
in closed-loop systems.
Most geothermal heat pumps provide summer air conditioning, but
a few brands are designed only for winter heating. Sometimes these
heating-only systems incorporate a groundwater cooled coil that
can provide cooling in moderate climates.
Geothermal heat pumps can also differ in the way they are designed.
Self contained units combine the blower, compressor, heat exchanger
and coil in a single cabinet. Split systems allow the coil to
be added to a forced-air furnace and utilize the existing blower.
Will
I have to add insulation to my home if I install one of these
systems?
Geothermal heat pumps will reduce your heating and cooling
costs regardless of how well your home is insulated. However,
insulating and weatherizing are key factors in realizing the most
savings from any type of heating and cooling system.
Can
a geothermal heat pump also heat water?
Yes. Using what's called a desuperheater, some types of
geothermal heat pumps can save you up to 50 percent on your water-heating
bill by preheating tank water. Desuperheaters are standard on
some units, optional on others. Some geothermal models can provide
all of your hot water needs on demand at the same high efficiencies
as the heating/cooling cycles.
Is
a geothermal heat pump difficult to install?
Most units are easy to install, especially when they are
replacing another forced-air system. They can be installed in
areas unsuitable for fossil fuel furnaces because there is no
combustion, thus, no need to vent exhaust gases.
Ductwork must be installed in homes that don't have an existing
air distribution system. The difficulty of installing ductwork
will vary.
Can
geothermal heat pump be added to my fossil fuel furnace?
Split systems can easily be added to existing furnaces
for those wishing to have a dual-fuel heating system. Dual-fuel
systems use the heat pump as the main heating source and a fossil
fuel furnace as a supplement in extremely cold weather if additional
heat is needed.
I
have ductwork, but will it work with this system?
In all probability, yes. We will be able to determine
ductwork requirements and if any minor modifications are needed.
Do
I need to increase the size of my electric service?
Geothermal heat pumps don't use large amounts of resistance
heat, so your existing service may be adequate. Generally, a 200-amp
service will have enough capacity, and smaller amp services may
be large enough in some cases.
Should
I buy a heat pump large enough to heat with no supplemental heat?
We can provide a heating and cooling load calculation
(heat loss, heat gain) to guide your equipment selection. Geothermal
heat pumps are sized to meet your cooling requirements. Depending
on your heating needs, a geothermal heat pump will supply 80-100
percent of your design heating load. Sizing the heat pump to handle
your entire heating needs may result in slightly lower heating
costs, but the savings may not offset the added cost of the larger
heat pump unit. Also, an oversized unit can cause dehumidification
problems in the cooling mode, resulting in a loss of summer comfort.
Do
geothermal heat pumps have outdoor units?
No. The equipment goes inside your home, usually
in the basement, garage, crawl space, or mechanical room.
Because it's indoors, the life spans of the compressor and
major components are greatly extended, most having a life
span of 20 years or more.
Ask
us to conduct a study on your system to see what you can
save.
