Underground solar energy storage via energy piles

Ma, Qijie; Wang, Peijun

doi:10.1016/j.apenergy.2019.114361

Cited by 37 publications

(11 citation statements)

References 41 publications

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“…The steady-state temperature in the soil for the group pile foundation is higher than that for the isolated pile due to the thermal interactions between adjacent piles [12,[15][16][17][18][19]. The more piles in a group, the higher the soil's temperature was observed [18,19]. Since the thermal transfer mechanism is similar between the thermo-active pile and the energy storage pile, comparisons of the temperature distributions between these two applications are conducted in this paper, although the loading conditions are quite different for these two cases.…”

Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

“…Previous experimental and analytical studies on the thermo-active pile foundation have shown that the temperature changes and thermal-induced stresses in the soil are not critical under the operating conditions of typical applications [8][9][10][11][12][13][14][15][16][17][18][19]. However, the temperature changes in the soil may become significant under extreme thermal loading conditions (up to 30 • C) due to intensive uses of the energy piles [12,14,15,18]. The steady-state temperature in the soil for the group pile foundation is higher than that for the isolated pile due to the thermal interactions between adjacent piles [12,[15][16][17][18][19].…”

Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

“…However, the temperature changes in the soil may become significant under extreme thermal loading conditions (up to 30 • C) due to intensive uses of the energy piles [12,14,15,18]. The steady-state temperature in the soil for the group pile foundation is higher than that for the isolated pile due to the thermal interactions between adjacent piles [12,[15][16][17][18][19]. The more piles in a group, the higher the soil's temperature was observed [18,19].…”

Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

“…Similar thermal transfer analyses and temperature distribution studies were conducted extensively for thermo-active pile foundations [8][9][10][11][12][13][14][15][16][17][18][19]. In these studies, the pile was treated as a heat absorber for heat exchange between the ground surface and underground regions since the temperature at the ground surface fluctuates seasonally while the underground temperate remains constant.…”

Section: Introductionmentioning

confidence: 99%

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Group Pile Effect on Temperature Distributions inside Energy Storage Pile Foundations

et al. 2020

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Energy storage pile foundations are being developed for storing renewable energy by utilizing compressed air energy storage technology. Previous studies on isolated piles indicate that compressed air can result in pressure and temperature fluctuations in the pile, which can further affect safety of the pile foundation. Meanwhile, the temperature changes and distributions for the pile and surrounding soil also are influenced by adjacent piles in typical group pile constructions. Therefore, dynamic thermal transfer simulations were conducted in this paper to investigate the temperature changes and distributions in the concrete pile and surrounding soil for group pile construction. The main parameter in this study is the spacing of the piles. The analysis results show that the group pile effect significantly increases the temperature up to more than 100 °C depending on the location and changes its distribution in both concrete and soil due to the heat transferred from the adjacent piles. The final stabilized temperature can be as high as 120 °C in the concrete pile and 110 °C in the soil after numerous loading cycles, which is about 4 times higher than typical thermo-active energy pile applications. Thus, it is important to include the group pile effect for design and analysis of the energy storage pile foundation.

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Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

Section: Performacne Of Thermal-active Energy Pilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Group Pile Effect on Temperature Distributions inside Energy Storage Pile Foundations

et al. 2020

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“…From previous studies, Sani and Singh [ 23 ] and Péron et al [ 36 ] pointed out that the influencing radii of temperature in sandy soil, silt soil, and clay are 6 m, 5 m, and 4 m, respectively. Moreover, Ma and Wang [ 37 ] found that when the clearance distance between the lower boundary of the ground and the bottom of the energy pile is more than 10 m in the numerical simulation, the influence of the bottom boundary on the temperature change of the ground can be ignored to a certain extent. Therefore, the ground with a radius of 10 m and a depth of 50 m is set as the calculation area of the numerical model, and the PHC pile is located at the center of the ground ( Figure 9 ).…”

Section: Numerical Simulation and Analysismentioning

confidence: 99%

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

Zhang

Cao

Liu

et al. 2021

Sensors

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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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Review of borehole thermal energy storage systems in unsaturated soils: Materials, mechanism, and future development

Zeng,

Cheng,

Yang

2024

Energy Storage

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Borehole thermal energy storage (BTES) is an innovative renewable energy technology for building heating and cooling. The lack of studies about BTES in unsaturated soils acts as a barrier to further implementation. In this study, the research obstacles, progress, hotspots, and differences between countries of BTES systems in unsaturated soils were described in detail based on a literature review, bibliometric analysis, technology roadmap, and data visualizations. The results show that the process of coupled heat and moisture transfer has been a research hotspot in recent years, and the thermo‐hydraulic properties increase the complexity of analysis. There are few studies on experimental data and engineering practices of BTES systems in unsaturated soils. China is leading in publications number, but European and North American countries perform better in international cooperation and policy incentives. Technology development will be directly driven by policy momentum, followed by the gradual establishment of a complete research, design, and evaluation system, which helps accelerate the replacement of traditional fossil energy with renewable energy. In an attempt to improve society's awareness and move forward with scientific foresight of BTES systems in unsaturated soils, this review has revealed the evolutionary process, identified its current status, and depicted the future development from political, economic, social, and other dimensions.

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Underground solar energy storage via energy piles

Cited by 37 publications

References 41 publications

Group Pile Effect on Temperature Distributions inside Energy Storage Pile Foundations

Group Pile Effect on Temperature Distributions inside Energy Storage Pile Foundations

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

Review of borehole thermal energy storage systems in unsaturated soils: Materials, mechanism, and future development

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