Geothermal Segments: The Tunnel as Heat Supplier

Figure: Rehau/Züblin

Installation of the geothermal segments in the Jenbach Tunnel, Lot H8

Figure: Rehau/Züblin

Tunnel lining with segments for energetic activation

Figure: Rehau/Züblin

Production of a geothermal segmenet: The absorber pipes (grey) are attached to the reinforcement

Figure: Rehau/Züblin

Thermal activation of the 54 m long section of the Jenbach Tunnel: absorber circuit between tunnel collector and building yard

Figure: Rehau/Züblin

Scheme of the heating circulation

Figure: Rehau/Züblin

Simulation of the extraction rate in permanent and interval operation

Figure: Rehau/Züblin

Measurement series with Re≈1,650, practical operation

Figure: Rehau/Züblin

Test set-up in Jenbach with cooling unit

Figure: Rehau/Züblin

Measurement series with cooling unit at Re≈1,200, test operation

Figure: Rehau/Züblin

Measurement series with cooling unit at Re≈2,300, test operation

Figure: Rehau/Züblin

Measurement series with cooling unit at Re≈4,200, test operation

Figure: Rehau/Züblin

Estimated extraction rate from “hot” and “cold” tunnels at a flow temperature of 5 °C

Figure: Rehau/Züblin

Extraction rate depending on tunnel type and tunnel length

Figure: Rehau/Züblin

Simple payback of tunnel types

Figure: Rehau/Züblin

In the course of the upgrading of the railway route from Munich to Verona, a part of a tunnel in the area of Jenbach in the Tyrol has been thermally activated. It now supplies geothermal energy to the nearby utility centre.

Thanks to the logging of data from the operation of the Jenbach thermal power plant since 2012, and also from additional tests, it is now possible to make more detailed statements about the energy potential and opportunities of energetic activation. The heat, which in this case is extracted from quite a shallow depth, is used for heating and cooling purposes in buildings and transport structures with a potential extraction rate of 25 to 40 W/m². It has been demonstrated that the payback period is of the same order as normal geothermal plants.