Thermal resistance analysis of an energy pile and adjacent soil using radial temperature gradients

Faizal, Mohammed; Bouazza, Abdelmalek; McCartney, John S.

doi:10.1016/j.renene.2022.04.002

Cited by 23 publications

(2 citation statements)

References 57 publications

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“…It has also been found that the thermal conductivity of the soil around a pile also greatly influences that of the energy pile [4][5][6]. In addition, in a parameter analysis, the pile length, number of pipes, and liquid volume flow also have a large influence on the thermal conductivity of energy piles, while the concrete cover and pile diameter only have a small impact [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

Xu,

Wang,

Meng

et al. 2024

Buildings

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The global demand for energy is on the rise, accompanied by increasing requirements for low-carbon environmental protection. In recent years, China’s “double carbon action” initiative has brought about new development opportunities across various sectors. The concept of energy pile foundation aims to harness geothermal energy, aligning well with green, low-carbon, and sustainable development principles, thus offering extensive application prospects in engineering. Drawing from existing research globally, this paper delves into four key aspects impacting the thermodynamic properties of energy piles: the design of buried pipes, pile structure, heat storage materials within the pipe core, and soil treatment around the pile using carbon fiber urease mineralization. Leveraging the innovative mineralization technique known as urease-induced carbonate mineralization precipitation (EICP), this study employs COMSOL Multiphysics simulation software to analyze heat transfer dynamics and establish twelve sets of numerical models for energy piles. The buried pipe design encompasses two types, U-shaped and spiral, while the pile structure includes concrete solid energy piles and tubular energy piles. Soil conditions around the pile are classified into undisturbed sand and carbon fiber-infused EICP mineralized sand. Different inner core heat storage materials such as air, water, unaltered sand, and carbon fiber-based EICP mineralized sand are examined within tubular piles. Key findings indicate that spiral buried pipes outperform U-shaped ones, especially when filled with liquid thermal energy storage (TES) materials, enhancing temperature control of energy piles. The carbon fiber urease mineralization technique significantly improves heat exchange between energy piles and surrounding soil, reducing soil porosity to 4.9%. With a carbon fiber content of 1.2%, the ultimate compressive strength reaches 1419.4 kPa. Tubular energy piles mitigate pile stress during summer temperature fluctuations. Pile stress distribution varies under load and temperature stresses, with downward and upward friction observed at different points along the pile length. Overall, this research underscores the efficacy of energy pile technologies in optimizing energy efficiency while aligning with sustainable development goals.

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Section: Introductionmentioning

confidence: 99%

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

Xu,

Wang,

Meng

et al. 2024

Buildings

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“…In the field tests, Laloui et al [6] conducted an experimental study of the stress-strain characteristics of piles under coupled temperature-structure loading and found that the additional thermal stress exceeded the maximum internal stress of the pile when the superstructure load was applied due to thermal effects. Faizal et al [7,8] conducted a temperature cyclic loading study on energy piles in a 6-story building and found that the pile axial stresses were mainly caused by axial thermal strains, and the magnitude of the axial stresses depended on the pile end restraint. Brandl et al [1] found that not only does the pile temperature change during heat transfer, but also the pile-soil interface might cause engineering problems during heat transfer from the pile to the soil.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Thermo-Mechanical Behavior of a Novel Energy Pile with Phase Change Materials Using Fiber Bragg Grating Monitoring

Cui,

Shi,

et al. 2023

Sustainability

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The combination of phase change materials (PCMs) with building materials is a flourishing technology owing to the low-temperature change of the materials during phase change and the potential for enhanced heat storage and release. In this study, a new type of PCM energy pile, in which 20 stainless steel tubes (22 mm in diameter and 1400 mm in length) filled with paraffin were bound to heat exchange tubes, was proposed. An experimental system monitored by a fiber Bragg grating (FBG) to study the thermo-mechanical behavior of energy piles and surrounding soil was established. Both the PCM pile and the ordinary pile, with the same dimensions, were tested under the same experimental conditions for comparison. The results indicate that the temperature sensitivity coefficient calibration results of the FBG differ from the typical values by 8%. The temperature variation is more obvious in the ordinary pile and surrounding soil. The maximum thermal stress of the ordinary energy pile is 0.5~0.6 times larger than that of the PCM pile under flow rates ranging from 0.05 m3/h to 0.25 m3/h. The magnitudes of the pore water pressure and soil pressure variations were positively correlated with the flow rates.

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Analytical Model for Heat Transfer Around Energy Piles in Layered Soil With Interfacial Thermal Resistance by Integral Transform Method

Zhou,

Zhang,

Sun

et al. 2024

Num Anal Meth Geomechanics

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Energy piles are commonly deployed in vertically layered geological conditions due to the geological structure and pile foundation backfill. The imperfect contact between adjacent soil layers results in resistance to heat transfer at the interface, known as the interfacial thermal resistance effect. In this paper, the energy pile was simplified as a finite‐length solid cylindrical heat source, and an analytical model was established for layered heat transfer of energy piles considering the interfacial thermal resistance effect. The Laplace‐domain solutions to the temperatures in the layered ground were derived by using the finite Hankel and Laplace transforms. The Crump method was subsequently employed to numerically invert Laplace‐domain solutions to the time‐domain solutions. The proposed model was validated by comparing with an analytical solution of a homogeneous model and COMSOL numerical solution. These solutions were used to analyze the temperature response around energy piles considering interfacial thermal resistance. Finally, a parametric study was performed to explore the effects of interfacial thermal resistance and other thermal properties of the soil layer on the layered heat transfer of energy piles.

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Thermal resistance analysis of an energy pile and adjacent soil using radial temperature gradients

Cited by 23 publications

References 57 publications

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

Experimental Study on Thermo-Mechanical Behavior of a Novel Energy Pile with Phase Change Materials Using Fiber Bragg Grating Monitoring

Analytical Model for Heat Transfer Around Energy Piles in Layered Soil With Interfacial Thermal Resistance by Integral Transform Method

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