Long-Term Thermo-Hydraulic Numerical Assessment of the Sustainability of Thermo-Active Piles – Case of Tropical Soils

Thermo-active piles are an upcoming technology for the utilization of subsurface geothermal energy in urban areas. This environmentally friendly technology has already been widespread for the heating and cooling of buildings in temperate regions, whereas in tropical regions it is still limited due to their unbalanced energy demands. This paper presents 3D thermo-hydraulic coupled numerical simulations to assess the long-term performance of thermo-active pile systems in tropical environments for different energy demands. The simulations are based on real data (in situ tests and field investigations) considering three typical thermal solicitations, thereby maintaining its practical relevance. Moreover, the energy exchange within soil control volumes is quantified based on an approach which allows calculating conductive and advective divergence. Parametric analyses regarding thermal solicitation, pile diameter and groundwater flow are also performed. The results indicate that groundwater flow plays the most important role in improving the thermal balance of thermo-active piles