1. Watch this video : GeoExchange heating and cooling system.
(vidéo à préparer pour le 10 mars; vous recevrez la transcription ce jour-là)
NB Comme le précise bien le présentateur de l’une des vidéos de Worcester-Bosch mentionnées ci-dessous, et contrairement à ce que proclame la première image de cette vidéo (« Geothermal finally explained ! »), « It must be emphasized that this is ground-source heat and NOT geothermal energy. Forget the hot springs in Iceland and all that sort of things, this is just using the sun’s rays which are stored in the ground as heat, to heat your home. »
2. You might be interested in these videos by Worcester-Bosch. They explain the various types of ground-source heat pumps and show their installation.
3. On the GeoExchange website (« a non-profit trade association promoting the manufacture, design and installation of GeoExchange® systems »), you’ll find lots of interesting information : brochures, data sheets… (« consumer resources » and « library » tabs)
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màj 18 mars : Transcript
Because the earth absorbs and stores much of the energy it receives from the sun as heat,
underground temperatures remain constant at a point between 42 and 80°F year round
depending on where you are in the United States.
A GeoExchange system can use this energy source
to economically heat and cool almost any kind of building,
heat water, provide refrigeration
and perform many other kinds of applications.
0:33 A GeoExchange system is made up of three components :
a heat pump, usually located inside the building,
where it’s protected from the environment and vandalism ;
an underground heat exchanger to act as a heat sink
to store energy in the earth when cooling
and to extract energy from the earth when heating ;
and a distribution system such as air ducts
or hydronic radiant floor tubing
to provide comfort control for the building space.
1:04 The two types of heat exchangers commonly used are open loop and closed loop.
A closed loop system uses a system of continuous underground pipe loops
in which both ends of the pipe system are connected to the heat pump,
thereby forming a sealed closed loop.
Water or a mixture of water and environmentally friendly anti-freeze
circulates through the loop to transfer heat
between the heat pump and the earth.
1:33 In some installations, the pipes of a closed loop system
can be placed in a horizontal trench
dug below the frost line.
The number of pipes in each trench
and the number of trenches needed
will vary depending on the size of the GeoExchange system being installed
and the type of soil found in the area.
1:53 To minimize trenching,
Slinky (™) coils – spring-like coils of polyethylene pipe –
can often be used to increase the pipes’ surface area
and thus the heat-exchange per foot of trench.
Another way to increase the heat-exchange rate of a closed loop system
is to take advantage of the naturally higher heat-transfer capability of water over soil or rock.
If a stream, river or pond of sufficient size is available
coils of heat-exchanger pipe can be installed on or near the bottom
to form a pond loop system.
2:30 In locations where space is limited
or a large heat exchanger is required,
the pipes of a closed loop GeoExchange system can be installed vertically
in wells drilled into the earth.
As with the horizontal and pond loop systems,
the number of loops and the depth of the wells needed in a vertical closed loop system
are determined by the size of the building,
system demands,
the ground temperature
and other variables.
2:59 Since it’s not necessary for the heat exchanger to be connected to the rest of the system above ground
whichever type is installed can be placed within existing landscaping :
under sidewalks, driveways and parking lots
or even beneath the building itself.
In an open loop system, on the other hand,
ground water from an aquifer is pumped through one well
and passes through the heat pump
where heat is added to or extracted from it.
The water is then discharged back to an aquifer
or harnessed for other water management uses.
Because the system’s water supply and discharge are not connected underground,
the loop is open. (3:42)
