Constructive recommendations for optimized and reliable heat exchanger pile systems

• Research unit: SFOE
• Project number: 103357

Short description (English)

Heat exchanger piles use the geothermal energy to heat or cool buildings by absorbing and transporting ground thermal energy to the buildings via fluid pipes cast in the piles (with a heat pump or a cooling machine). For years, the dimensioning of heat exchanger pile installations has relied on heat transfer calculations only. There is currently no method for the geotechnical design taking into account the effects of temperature cycles applied to the pile/soil system. Geotechnical engineers therefore systematically over-estimate the design of heat exchange piles with respect to classical piles. There is room for improvement of this empirical design in order to decrease the economical cost and increase the energy (and environmental) efficiency of the system. This will achieved by considering the complex interaction between mechanical properties of the soil-foundation system, temperature and ground pore water. Our objective is to derive constructive recommendations for heat exchanger piles, based on a scienti fic knowledge of the interaction between the energy demand and the thermal behaviour of the soil.