09-07-2012, 03:39 PM
GROUND SOURCE COOLING SYSTEM
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INTRODUCTION
This project report deals in depth with our project
this project we have designed and established
have a future alternative to traditional heating,
and air conditioning systems. Closed Loop
Ground Source Cooling System
relatively constant temperature of the ground
to regulate the temperature of a home or
building at very high effective efficiency.
system does not create heat through
combustion of fuel or passing electricity
through resistors; it moves heat from the
ground to the home/building for heating and
the opposite direction for cooling.
TYPES OF GROUND SOURCE HEAT PUMP
Closed Geothermal Ground Loops
The most typical geothermal installation utilizes a closed loop system. In a closed loop system, a
loop of piping is buried underground and filled with water or antifreeze that continuously circulates
through the system. There are four major types of closed loop geothermal systems: horizontal
loops, vertical loops, slinky coils and pond loops.
Horizontal Geothermal Ground Loops
If adequate soil or clay based land is available,
horizontal geothermal ground loops are typically
one of the more economical choices. In horizontal
geothermal ground loops, several hundred feet of
five to six feet deep trenches are dug with a
backhoe or chain trencher. Piping is then laid in
the trench and backfilled. A typical horizontal
ground loop will be 400 to 600 feet long for each
ton of heating and cooling.
Vertical Geothermal Ground Loops
When extreme climates, limited space or rocky
terrain is a concern, vertical geothermal ground
loops are often the only viable option. This makes
them popular for use on small lots and in retrofits.
In vertical geothermal ground loops, a drilling rig
is used to drill 150 to 300 foot deep holes in which
hairpin shaped loops of pipe are dropped and then
grouted. A typical vertical ground loop requires
300 to 600 feet of piping per ton of heating and
cooling. Vertical loops are typically more
expensive than horizontal loops, but are
considerably less complicated than drilling for
water. Less piping is also required for vertical
geothermal ground loops as opposed to horizontal
loops as the earth temperature is more stable at
depth.
Slinky Coil Geothermal Ground Loops
Slinky coil geothermal ground loops are gaining popularity, particularly in residential geothermal
system installations. Slinky coil ground loops are essentially a more economic and space efficient
version of a horizontal ground loop. Rather than using straight pipe, slinky coils, as you might
expect, use overlapped loops of piping laid out horizontally along the bottom of a wide trench.
Depending on soil, climate and your heat pumps run fraction, slinky coil trenches can be anywhere
from one third to two thirds shorter than traditional horizontal loop trenches.
Geothermal Pond Loops
If at least a ½ acre by 8 ft deep pond or
lake is available on your property, a closed
loop geothermal system can be installed by
laying coils of pipe in the bottom of a body
of water. However, a horizontal trench will
still be needed to bring the loop up to the
home and close the loop. Due to the
inherent advantages of water to water heat
transfer, this type of geothermal system is
both highly economical and efficient.
Open Geothermal Ground Loops
With open geothermal ground loops, rather than continuously running the same supply of water or
antifreeze through the system, fresh water from
a well or pond is pumped into and back out of
the geothermal unit. Both an abundant source of
clean water and an adequate runoff area are
required for a successful open loop system.
While double well designs can be economical,
use of open geothermal ground loops is generally
discouraged and even prohibited in some
jurisdictions. Water quality is key to an open
loop design as mineral content and acidity can
quickly damage geothermal units. Also,
improper installation or runoff management of
an open loop geothermal system can result in
ground water contamination or depleted
aquifers.