Challenge:

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Saas-Fee is the first high-alpine community in Switzerland to receive a solar district heating network with geothermal probe storage. When fully developed, the district heating network will cover a heat demand of 20 GWh. The realization of the district heating network requires 92 boreholes of 170m each, which were constructed in a very short time, and a thermal solar plant of 1'300m2.

Solution:

Due to the high alpine location of Saas-Fee, boreholes for the geothermal probes can only be drilled in a narrow time window. Initially, GW Geowärme AG started with one drilling rig. The number was later increased to 3 drilling rigs in order to complete the geothermal probe field on schedule.

Design
The project is considered as a real innovation, which is also in line with the goals of the nationwide energy policy. With the solar district heating network, the surplus solar energy from the summer is stored in a geothermal reservoir and made available in the winter. The test drillings carried out in advance were successful. The rock available in Saas-Fee is very well suited as an earth reservoir.

Installation manhole
The 92-unit manhole type 4 with connections on both sides was delivered on schedule by truck and hoisted by crane to the designated location.
Since the excavation pit for the shaft is crossed by existing pipelines, it had to be enlarged and the shaft placed under the pipelines.
One of the pipelines had to be extended, but this was no problem for Lauber IWISA AG, as a specialist company. The manhole was placed under the pipelines

Connecting the geothermal probes:

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The entire connection lines of the geothermal probes to the distribution shaft as well as the lines for the district heating network were constructed by Lauber IWISA AG. The wellnessHostel4000 and the Aqua Allalin will be the first customers to be supplied from the district heating network this winter. The connection of further objects will take place in the coming years.

Construction:

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Saas-Fee
Schweiz

Eingesetztes Produkt:

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• 92 pcs. Double-U HakaGerodur GEROtherm^® geothermal probes
  - Length 170 m
  - Pipe material: PE 100-RC
  - de 40 mm

• Manhole type 4
  92 pcs. probe connections on both sides