Testing of an Enertun segment prototype in Turin metro line 1

Since the 1980s, a number of underground geotechnical structures have been turned into heat exchangers, the so-called energy geostructures, by embedding absorber pipes in their concrete mass. A carrier fluid circulating along the pipes extracts or injects heat from or into the ground with the aim of conditioning buildings. A novel energy tunnel precast seg- mental lining was patented at Politecnico di Torino in 2016. Compared to previous configur- ations, this patent suggests an innovative and more efficient layout of the net of pipes. The South Extension of Turin Metro Line 1 represented an extraordinary opportunity to test the novel energy segment. This paper is intended to describe the experimental site setup, by outlin- ing the operation modes and the experimental campaign carried out. A preliminary coupled thermo-hydraulic, finite-element numerical analysis was also developed with the intention of performing a comparison with the experimental measurements.