A novel low enthalpy geothermal energy system based on ground freezing probes

Geothermal energy plants allow both heating and cooling of buildings by using the ground as a renewable energy source. The present work shows the numerical results obtained for the recovery of the freezing probes used for the Artificial Ground Freezing (AGF) technique of the two tunnels between Line 1 and Line 6 of the new Metro station in Piazza Municipio, Napoli. The AGF is a consolidation technique used in geotechnical engineering. The recovered probes are connected to a geothermal heat pump. The authors propose to develop an ad hoc innovative plant, in accordance with the principles of the Industry 4.0. In particular, the authors have developed a thermo-fluid dynamic numerical model, solved by means of finite elements, in order to design an innovative energy system, recovering the freezing probes installed for the excavation of the two tunnels.