Challenge:

‎
The new energy concept of ETH Zurich aims to use as much "low-value" energy (anergy) as possible for heating and cooling purposes. The anergy at the Hönggerberg campus is geothermal energy and waste heat. The largest anergy network in Switzerland currently consists of three dynamic probe fields with a total of around 440 geothermal probes. Geothermal probes of 200m each, which are connected underground via a 1km long ring line.

Solution:

‎
With the Science City project, ETH Zurich is pursuing the goal of developing its Hönggerberg site into a model of a sustainable campus and expanding the campus as an international hub of science, business and the population. New, sustainable building complexes are being constructed in various construction phases.

Execution

The third probe field of the ETH Zurich anergy network was constructed within only two months. Up to a total of seven drilling rigs of e-therm AG were active on the construction site. The drilling teams completed one complete geothermal probe per day, including backfilling. For the sinking of the GEROtherm^® geothermal probes a 24 kg cast weight was sufficient. Thanks to the special probe winding, installation is unproblematic.
Pressure testing of each probe is carried out after backfilling of the borehole to confirm the tightness of the geothermal probes. The tight schedule was kept by the drilling masters of e-therm AG and the connection lines from a reel could also be installed in a very short time.

Installation Distributor

The custom-built 19 SAVE180 Collectors/­Distributors combine the 208 borehole heat exchangers. The SAVE180 distributor pairs were equipped with ball valves only, without balancing valves, since nearly identical pressure losses per probe and tie-in line were to be expected.
The energy for heating or cooling is transferred to the anergy network via the collectors/­distributors.

A total of four loop lines are installed in the existing ducts, with the lines for heating and cooling having an outside diameter of 56 cm (d560).

Construction:

‎
ETH Hönggerberg 3rd Stage
Zürich, Schweiz

Used Products (3rd Stage):

• 208 pcs. Double U-probes GEROtherm^® geothermal probes Incl. injection pipes and weights
• Length 200 m, de40
• 14'000m de50 PE100-RC connection pipes
• 19 pcs. SAVE180 distributor pairs

• All three stages together:

  
  440 pcs. GEROtherm^® geothermal probes