Geothermal energy in underground structures
A team from the Swiss Federal Institute of Technology in Lausanne (EPFL) has teamed up with Amberg Engineering to investigate the geothermal potential of subway stations and underground data centers. In the first case, the focus was on heat recovery, in the second on cooling.
Engineers from the Laboratory of Soil Mechanics(LMS) at EPFL have investigated the use of geothermal energy in two very different applications: in a subway station and in an underground data center . In this Innosuisse project, the researchers, together with the internationally active engineering firm Amberg Engineering from the canton of Zurich, focused on optimizing air conditioning through the improved use of energy geostructures.
These are building components that are located in the ground and can be used for heat conduction. These include energy piles, floor slabs and basement walls. The two studies were published in the journal “Tunnelling and Underground Space Technology”.
The transferable models developed by the team took into account either most of the physical factors of the underground railroad infrastructure or the capacity to dissipate excess heat through geothermal activation, in addition to the geometry of the building and mechanical ventilation.
Among other things, the researchers found that a geothermal system in an underground data center pays for itself in three to seven years. If geothermal energy replaces the heat generated by gas boilers, annual CO2 emissions at the typical site in this case study could be reduced by 45 percent.
Sofie ten Bosch, a civil engineer at LMS and lead author of the study, was able to apply her PhD research to two specific applications in these two studies. She says: “The technology to assess the potential of geothermal energy in a given area is now mature and we see that the industry is ready to explore new opportunities for the optimal use of this sustainable heat source.”