Terrestrial heat probe
fields
Detailed information
For approximately one decade terrestrial heat probe fields for the heat
supply are realized, which are used partly also for the cooling during the
summer. These terrestrial heat probe fields consist of a series of
drillings, which are generally equipped with two U-tubes from polyethylene
for the heat exchange with the ground. The drillings are filled with a
mixture from cement and Bentonit, in order to guarantee a good thermal
contact between the U-tubes and the drillinghole wall. The necessary
number of drillings (4 to 80) as well as their depth (30 to 350 m) depends
of the heat requirement and local geological conditions.
The THP are built as close as possible to the building which should be
supplied. The lines of the individual THP's are united and supply in such
way one or more heat pumps. For heating with low temperature as well as
for cooling, a heat transfer liquid is circulating in the floor or in the
ceiling of the building.
The function is based on an annual cycle: during the winter the warmth
is withdrawed from the ground (cooling of the ground). In the summer, if
one cools, stored cold weather is again withdrawed from the ground
(heating up of the ground). The building cooling with “free cooling”
is energetically seen particularly favourable, since this runs exclusively
over the EMS and without refridgerator.
Since THP fields are more complex and more cost-intensive than a single
THP for a family house, it is important to define the dimension the
complete system correctly in advance, on the basis of the warmth and cold
needed . Once the the plant is operating, a proper computerized monitoring
during two years, allows a proper and optimized parametring of the system.
The necessary planning bases are provided by computer simulations.
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