The Geothermal concept
has been commercially available since around the 1940s. Greater
manufacturing and training improvements have made geothermal systems reliable and energy efficient. With system efficiencies
approaching 400%, geothermal systems can supplement or replace
your heating and hot water systems and reduce annual operating costs by 50% or more.
Geothermal systems use several approaches to connect to the stored solar energy in the Earth - via copper or plastic pipe (direct exchange or water source) in the ground or via plate heat exchangers in the ocean or a pond.
Direct Exchange uses copper refrigerant lines
in the ground and water source uses a plastic line in the ground
that is filled with a propylene glycol / water mix. Both are reliable, can be installed
many ways, and are Energy Star rated systems.
|We are dealers for
Earthlinked Technologies, the world leader in direct exchange geothermal
systems. These systems use copper refrigerant lines to couple to
the earth and extract or dispose of heat (depending on heating or
cooling mode). Many of our customers are curious about the durability
of the copper underground. The Copper Council of America has deemed
that these lines should last virtually indefinitely in non-aggressive
soil. For problem areas, anode protection (similar to a zinc bar
on a boat hull) systems ensure that the copper experiences no corrosion.
The refrigerant in the lines in non toxic and will not hurt the
aquifer or the ozone.
With Direct Exchange, there are three ways that we can couple to
the earth - horizontally, vertically, or diagonally. In all installations,
the copper lines are installed into manifolds that must be six feet
below finish grade. These manifolds are then connected to two main
refrigerant lines that extend into the building and are connected
to an EarthLinked heat pump. This heat pump is then connected to
a new or existing heating, cooling, or hot water system.
In a direct exchange horizontal installation, we install our refrigerant
lines at six feet below finish grade. You will need approximately
one square foot of usable yard per one square foot of conditioned
space. The copper lines must be installed level within twelve inches
across the entire yard and must be placed in clean sand. These lines
are then connected to manifolds and these manifolds are brought
into the building via two main refrigerant lines. These lines are
then connected to a heat pump, and the heat pump to your heating,
cooling, or hot water system.
In a direct exchange vertical installation, our drilling crew will
bore a four inch diameter hole one hundred foot deep. We shall then
install a refrigerant line in this hole and grout the hole with
a MA approved bentonite grout. The copper refrigerant line installed
in this single hole will produce one ton or 12,000 BTUs of heating/cooling
capacity. Additional holes are installed for every additional ton
of heating/cooling required. These lines are then installed together
into a manifold six feet below finish grade. The diameter of this
manifold pit is anywhere from the ten to twelve feet. These manifolds
are brought into the building via two main refrigerant lines. These
lines are connected to a heat pump, and the heat pump is connected
to your heating, cooling, or hot water system.
DX DIAGONAL: In a direct exchange diagonal installation, we perform
the same installation as the vertical type, but the surface pit
is smaller (about six feet). Each of the boreholes is typically
drilled at a 15 degree angle from the vertical. The lines extend
to the same hundred foot depth and are approximately 55 feet apart
at this depth. This installation is great for tight spaces or a
retrofit where the excavation of the pit is less intrusive.
SOURCE: We offer Climate Master, Bosch (Florida Heat Pump), and Water Furnace geothermal heat pumps. Water source
heat pumps use a black plastic high density polyethylene (HDPE)
pipe filled with a liquid such as water or propylene glycol to couple
to the ground and extract or reject heat (depending on heating or
cooling mode). There are many different ways to couple to the earth
with water source systems, such as open loop, closed loop, and Ocean
and lake plate type heat exchanger systems.
source open loop systems remove or extract heat from the earth by
drawing water out of the local aquifer, running this water through
a heat pump, and delivering it back to the aquifer. The heat pump
is then connected to your heating, cooling, or hot water system.
This is done with a draw and injection well, or a standing column
||This type of system
has two cased wells that are strategically placed to draw aquifer
water into the heat pump and then re-inject that same water back
into the aquifer.
of installation uses a single well. The water is drawn from the
bottom, sent through the heat pump, and returned to the top of the
well casing. These types of systems need to be very deep so that
the returned water has time to replenish the heat that has been
gained or lost.
types of systems are more common than the open loop systems. Closed
loop systems use HDPE lines to couple to the earth and remove or
add heat. These lines can be installed vertically or horizontally.
These lines are connected to a manifold and then connected to the
heat pump. The heat pump is then connected to your heating, cooling,
or hot water system.
|CLOSED LOOP HORIZONTAL:
There are many arrangements for the installation of closed loop
horizontal installations. However, they all consist of HDPE pipe
and they are all installed below six feet. They can be installed
in trenches or fields. The most common type of installation is the
“Slinky” patter. Coils of HDPE pipe are arranged in
a “Slinky” pattern and are buried six feet down. This
creates the ground couple heat exchanger that is then connected
to the heat pump. We can assume approximately 2 -4 square feet of
yard to one square foot of conditioned space.
|CLOSED LOOP VERTICAL:
This installation uses large diameter bore holes (about 6 –
10 inches) cored into the earth. We can assume approximately 250
to 400 feet per ton (12,000 BTUs). An HDPE loop is installed into
each hole, and then the hole is filled with a bentonite grout as
required by the MA Ground Water Association and the DEP. These lines
are then connected together into a manifold and the manifold is
then connected to the heat pump. The heat pump is then connected
to your heating, cooling, or domestic hot water systems
|OCEAN / LAKE PLATE
TYPE HEAT EXCHANGER SYSTEMS: Plate type heat exchangers can be installed
in fresh water ponds, brackish water ways, or in the ocean. Plate
type heat exchangers eliminate the ground coupling installations
described with horizontal and bore hole type systems. This is a
very cost effective way to install a geothermal plant. Instead of
hundreds of feet of refrigerant or HDPE lines connected to the earth,
plate type systems use the solar energy stored in a waterway. The
plate is installed in the water with two lines connected the plate
with the heat pump. This system is filled with a food grade propylene
glycol that is completely non toxic.
STEEL PLATE EXCHANGERS: Stainless steel plate type heat exchangers
are used for strictly fresh water installations. A plate or multiple
plates are suspended from a dock or mounted on skids. The key to
fresh water installations is making sure that the pond is large
enough to be replenished by the sun faster than the heat is extracted.
TITANIUM PLATE EXCHANGERS: Titanium plate type heat exchangers are
used in brackish water or the ocean. Just like stainless steel plates,
they are suspended from a dock or mounted on skids. The great thing
about ocean plate heat exchangers is that the ocean is a giant solar
battery. Unlike fresh water installations, we do not have to worry
about removing more heat that we can use.