Abstract

Ground source heat pump (GSHP) systems, like thermal piles and walls, are considered to be an efficient solution for tapping geothermal energy. Despite the vast range of potential applications, current GSHP designs have very limited input from a geotechnical aspect. The main reason for this is that there are still many concerns about the thermal and geomechanical behavior of a ground heat exchanger (GHE) and the ground. In order to ensure the safety and durability of GSHP systems and infrastructure, it is necessary to find a valid method to investigate relevant geothermal and geomechanical problems. In this research, an implicit and in-house finite element method (FEM) code is developed, which can simulate thermo-hydro-mechanical(THM) coupling processes in geothermal problems. Additionally, a new thermo-elasto-plastic constitutive model is proposed to simulate the thermo-mechanical behavior of soil and the model is implemented in the code. The performance of the developed code is evaluated at three sites in London. The main aim is to investigate both short and long-term performance of: (i) the combined open and closed loop GSHP system installed in One New Change retail centre, (ii) a thermal wall installed at a Crossrail station and (iii) a thermal pile loading testing at the Lambeth College.