Understanding the Thermo-Mechanical Behaviour of Energy Piles

The heating and cooling of buildings worldwide represent a large amount of the energy needs and are one of the significant sources of CO2. Decreasing the environmental impact of residential and office buildings is of crucial interest. Energy geostructures are a sustainable solution to this problem and constitute a local, renewable and environment-friendly resource in accordance with actual energy requests. Any structure in direct contact with the ground, such as diaphragm walls, tunnel lining and anchors, slabs and pile foundations, can be used to help satisfy the operational energy requirements of the overall facility to which the structures belong. Energy piles are probably the most widely used. A system of pipes installed within the concrete, with a heat carrier fluid that circulates through it, can extract heat from the ground to satisfy the need for heat during the winter and can expel excess heat resulting from air conditioning during the summer. Consequently, the geostructure is subjected to an additional thermal load, which results in additional stresses and strains to be considered in the design practice. Despite the fast spread of this technology in the last decade, there is still a lack of knowledge about the thermo-mechanical behaviour of energy geostructures. Here, the recent advances in the research on energy geostructures are discussed.