Master of Science, University of Toledo, 2017, Civil Engineering

Heat exchanger piles are the thermo-active foundation system that can be used to extract geothermal energy for heating and cooling in the supported upper structures. Geothermal energy is a renewable, clean, efficient and cost-effective source of energy. The temperature below the Earth's surface remains relatively constant throughout the year but varies spatially with the earth depth. Piles are typically used as a main component of engineering structures, transferring the load from an upper structure to the supporting geological formation when necessary. The temperature gradient can be utilized by facilitating a circulating fluid inside the pile which can extract heat from the ground as well as release the heat to the ground during winter and summer seasons, respectively. As such these so-called heat exchange piles serve as both a structural component as well as a heat exchanging component. The main objective of this thesis is to numerically study the behavior of heat exchanger piles and surrounding soils under different scenarios. Different combinations of thermal, mechanical and hydraulic loadings were applied during the simulation of the heat exchanger pile using a finite element program, Code_Bright. Mechanical responses of the heat exchange pile were examined, along with the thermal and mechanical responses of soils. Some hydraulic scenarios were also explored. First, numerical simulations were carried out under the mechanical loading only, focusing on the thermo-mechanical behavior of heat exchanger pile. The mechanical properties of the pile were examined and the compressive stress was found to be maximum at the pile head and decrease along the pile depth during the application of the pure mechanical loading; whereas during the application of thermal loading with the mechanical loading, the compressive stress was found to be maximum around the mid-depth of the pile with minimum values at the ends. The point of maximum stress, referred as the point of inve (open full item for complete abstract)

Committee: Liangbo Hu (Committee Chair); Brian W. Randolph (Committee Member); Eddie Y. Chou (Committee Member) Subjects: Civil Engineering; Energy; Engineering; Geotechnology