On the influence of thermal cycles on the yearly performance of an energy pile

2018 ◽  
Vol 16 ◽  
pp. 32-44 ◽  
Author(s):  
Marianna Adinolfi ◽  
Rosa Maria Stefania Maiorano ◽  
Alessandro Mauro ◽  
Nicola Massarotti ◽  
Stefano Aversa
Keyword(s):  
Thermal Cycles ◽  
Energy Pile

scholarly journals Analysis of Bearing Characteristics of Energy Pile Group Based on Exponential Model

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6881
Author(s):  
Lichen Li ◽  
Longlong Dong ◽  
Chunhua Lu ◽  
Wenbing Wu ◽  
Minjie Wen ◽  
...  
Keyword(s):  
Analytical Model ◽  
Load Transfer ◽  
Mechanical Response ◽  
Field Tests ◽  
Pile Group ◽  
Exponential Model ◽  
Heating Process ◽  
Thermal Cycles ◽  
Energy Pile ◽  
The Cost

Energy piles are an emerging energy technology for both structural and thermal purposes. To support structure load, piles are always used in groups with raft; however, the cost and complexity of field tests and numerical modelling limits the research on the bearing characteristics of energy pile group. In this paper, exponential model was applied to simulate the thermo-mechanical soil-pile interaction of energy pile group. Axial load transfer (τ-z) analysis was first performed to calculate the shear stress distribution in the soil, then matrix displacement method was introduced to determine the thermo-mechanical response of energy pile group. The validity of the analytical model was tested against field tests and numerical results. A case study was further performed to analyze the influence of thermal cycles and arrangement of thermally active piles on the bearing response of the whole pile group. Test results show that with the thermally activated pile in pile group, (1) differential settlement increases with thermal cycle numbers; (2) the axial force of thermally active pile increases during heating process and decreases during cooling process, and this trend varies for the surrounding nonthermal piles; (3) induced load on thermal pile increases with thermal cycles, but decreases for nonthermal piles. The proposed analytical model is expected to serve as a simple and convenient alternative for the preliminary analysis on the bearing characteristics of energy group pile.

Laboratory Ageing Thermal Cycles of MV Cable Joints: results of different diagnostic techniques

2020 ◽  
Author(s):  
Johnny Borghetto ◽  
Alfredo Contin ◽  
Andrea Morotti ◽  
Andrea Pegoiani ◽  
Giovanni Pirovano ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
Thermal Cycles

scholarly journals Contactless temperature measurement in wire-based electron beam additive manufacturing Ti-6Al-4V

2021 ◽  
Author(s):  
F. Pixner ◽  
R. Buzolin ◽  
S. Schönfelder ◽  
D. Theuermann ◽  
F. Warchomicka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal Imaging ◽  
Temperature Profiles ◽  
Layer By Layer ◽  
Thermal Cycles ◽  
Cooling Rates ◽  
Geometric Boundary ◽  
Microstructural Characterisation ◽  
Local Misorientation

AbstractThe complex thermal cycles and temperature distributions observed in additive manufacturing (AM) are of particular interest as these define the microstructure and the associated properties of the part being built. Due to the intrinsic, layer-by-layer material stacking performed, contact methods to measure temperature are not suitable, and contactless methods need to be considered. Contactless infrared irradiation techniques were applied by carrying out thermal imaging and point measurement methods using pyrometers to determine the spatial and temporal temperature distribution in wire-based electron beam AM. Due to the vacuum, additional challenges such as element evaporation must be overcome and additional shielding measures were taken to avoid interference with the contactless techniques. The emissivities were calibrated by thermocouple readings and geometric boundary conditions. Thermal cycles and temperature profiles were recorded during deposition; the temperature gradients are described and the associated temperature transients are derived. In the temperature range of the α+β field, the cooling rates fall within the range of 180 to 350 °C/s, and the microstructural characterisation indicates an associated expected transformation of β→α'+α with corresponding cooling rates. Fine acicular α and α’ formed and local misorientation was observed within α as a result of the temperature gradient and the formation of the α’.

Thermal cycles and their effects during friction stir welding of AA7075 thicker plates with and without in‐process cooling

2021 ◽  
Vol 52 (3) ◽  
pp. 308-319
Author(s):  
T. Srinivasa Rao ◽  
M. Selvaraj ◽  
S.R. Koteswara Rao ◽  
T. Ramakrishna
Keyword(s):  
Friction Stir Welding ◽  
Thermal Cycles ◽  
Friction Stir

scholarly journals Numerical Simulation Research on Multi-field Coupling of Underground Energy Pile

2021 ◽  
Vol 1838 (1) ◽  
pp. 012061
Author(s):  
Qihui Zhou ◽  
Zhanjun Huang ◽  
Yong Wu ◽  
Huipeng Zhang ◽  
Yufeng Shi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Simulation Research ◽  
Energy Pile ◽  
Field Coupling

scholarly journals Field Test and Numerical Simulation on the Long-Term Thermal Response of PHC Energy Pile in Layered Foundation

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3873
Author(s):  
Guozhu Zhang ◽  
Ziming Cao ◽  
Yiping Liu ◽  
Jiawei Chen
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchange ◽  
Temperature Variation ◽  
Thermal Response ◽  
Ground Temperature ◽  
Short Term ◽  
Energy Pile ◽  
Backfill Soil ◽  
Short And Long Term

Investigation on the long-term thermal response of precast high-strength concrete (PHC) energy pile is relatively rare. This paper combines field experiments and numerical simulations to investigate the long-term thermal properties of a PHC energy pile in a layered foundation. The major findings obtained from the experimental and numerical studies are as follows: First, the thermophysical ground properties gradually produce an influence on the long-term temperature variation. For the soil layers with relatively higher thermal conductivity, the ground temperature near to the energy pile presents a slowly increasing trend, and the ground temperature response at a longer distance from the center of the PHC pile appears to be delayed. Second, the short- and long-term thermal performance of the PHC energy pile can be enhanced by increasing the thermal conductivity of backfill soil. When the thermal conductivities of backfill soil in the PHC pile increase from 1 to 4 W/(m K), the heat exchange amounts of energy pile can be enhanced by approximately 30%, 79%, 105%, and 122% at 1 day and 20%, 47%, 59%, and 66% at 90 days compared with the backfill water used in the site. However, the influence of specific heat capacity of the backfill soil in the PHC pile on the short-term or long-term thermal response can be ignored. Furthermore, the variation of the initial ground temperature is also an important factor to affect the short-and-long-term heat transfer capacity and ground temperature variation. Finally, the thermal conductivity of the ground has a significant effect on the long-term thermal response compared with the short-term condition, and the heat exchange rates rise by about 5% and 9% at 1 day and 21% and 37% at 90 days as the thermal conductivities of the ground increase by 0.5 and 1 W/(m K), respectively.

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