Carrier GT-S - Manual (Page 5)

Indoor & Outdoor Split
Geothermal Comfort Systems
Carrier Indoor & Outdoor Split Geothermal Heat Pumps - Rev.: 08/10/05 3
Vertical Loops are the ideal choice when available
land area is limited.
Drilling equipment is
used to bore small-
diameter vertical
holes. Two pipes
joined together with
a u-bend fi tting are
inserted into the
vertical bore. Bore hole depth ranges from 100-300
feet per system ton. Bores must be spaced from
10-15 feet apart and properly grouted. The land
space required ranges from 100-200 square feet per
system ton.
Pond (Lake) Loops are very economical to install
when a body of
surface water is
available, because
ex ca va tion costs are
mostly eliminated.
Coils or “slinky” mats
of pipe are simply
placed on the bottom
of the pond (lake). In most cases, 1/4 to 1/2 acre of
water surface, with a min i mum depth of 8-10 feet, is
needed for a typical res i dence.
Ground Water Systems
Open loop systems utilize ground water as a direct
energy source when
good quality water
is available at a
reasonable pumping
depth. A well must
have enough capacity
to deliver a minimum
of 1.5 gpm per system
ton during peak
op er a tion. Ditches, fi eld tiles, ponds and streams are
the most common discharge systems. Re in jec tion or
semi-closed recirculation wells can also be utilized
in some regions. In ideal con di tions, an open loop
ap pli ca tion can be the most eco nom i cal type of
system to install.
Closed Loop Systems
Closed Loop Systems consist of an underground
heat exchange network of sealed, high strength
poly eth yl ene plastic pipe and a Flow Controller
pumping module. When cooling, the loop fl uid
temperature will rise, and rejected heat is dissipated
into the cooler earth. Con verse ly, while heating, the
loop fl uid temperatures fall, and heat is absorbed
from the earth. Carrier Flow Controller pumping
modules utilize small wattage pumps to circulate the
water/antifreeze fl uid within the piping system. The
plastic heat exchange loop is closed and ther mal ly
fusion-welded at all connections in the same manner
as natural gas distribution lines. Closed loops do not
require a ground water supply or drain, and they are
not subject to mineral build up.
Closed Loops can be installed in vertical or
hor i zon tal confi gurations, or submerged in a
pond or lake. When designed properly, all three
alternatives operate with similar effi ciency. Carrier
high density poly eth yl ene plastic pipe is used for all
closed loop installations. Pipe con nec tions are heat
fused to form joints that are stronger than the pipe
itself. Carrier loop piping has a life expectancy in
excess of 50 years.
Horizontal Loops are often considered when
adequate land space
is available. The
pipes are placed in
trenches, excavated
by a backhoe or chain
trencher to a depth of
4-6 feet. De pend ing
on design, from 1-6
pipes are installed in each trench. Multiple pipe
and coiled “slinky” con fi g u ra tions are often used
to conserve land re quire ments and reduce overall
installed loop costs. Horizontal boring technology
can also be used to install u-bend loops 10-15 feet
deep with minimal landscaping disruption. Trench
lengths range from 100-400 feet per system ton.
Trenches must be spaced from 6-10 feet apart. The
overall land area required ranges from 750-1,500
square feet per system ton.