A New Type in TRNSYS 18 for Simulation of Borehole Heat Exchangers Affected by Different Groundwater Flow Velocities

Antelmi, Matteo; Turrin, Francesco; Zille, Andrea; Fedrizzi, Roberto

doi:10.3390/en16031288

Cited by 11 publications

(6 citation statements)

References 26 publications

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“…Meanwhile, the movement of the surrounding groundwater (aquifer) has a significant effect on the performance of the heat exchanger. Antelmi et al 26 have advanced a numerical model that is capable of simulating the main features and improving the design of borehole heat exchangers. The simulation can model the impact of different Darcy groundwater flow velocities (heterogeneous aquifer) on the exchanger performance due to different permeabilities within the soil layers.…”

Section: Introductionmentioning

confidence: 99%

Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

Kahwaji,

Capuano,

Boudekji

et al. 2024

Heat Trans

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Ground‐coupled heat exchangers (GCHE) have received significant attention over several decades as a result of increasing the world's energy demand and the need for reducing fossil fuels consumption. Prior studies have demonstrated the effectiveness of utilizing GCHE with refrigeration and heating systems. However, optimizing the performance of GCHE coupled with chillers for heat rejection, especially in extreme hot‐humid climates (where cooling towers are not very effective) is lacking in the literature. In this work, a ground borehole fitted with a coaxial‐tubes heat exchanger (BHE) is numerically simulated. Based on a wide range of data collected for the soil of Dubai, its real in situ thermophysical properties are characterized. The soil's upper layer thickness is relatively small and dry that operates in conduction mode, while the lower one is water‐saturated that works in coupled conduction‐advection mode. The study aims at optimizing the parameters advancing heat rejection into ground considering the actual properties of the soil of Dubai. The results indicate that the more feasible high‐density polyethylene pipes can perform as good as the steel ones. Also, a great finding based on the presented novel design is that insulating the inner pipe can increase the temperature duty by 55%. The proposed design of BHE is relatively inexpensive, more feasible and efficient, which is achieved for the first time based on a deep analysis of Dubai climate and soil. This makes the technology ready to be implemented for industrial applications in Dubai and other regions having a similar climate and soil nature.

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Section: Introductionmentioning

confidence: 99%

Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

Kahwaji,

Capuano,

Boudekji

et al. 2024

Heat Trans

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“…Casasso [22] conducted a simulation of the heat exchange of a borehole heat exchanger with soil and an aquifer system through FEFLOW 6.0. Antelmi and Vespasiano [23,24] proposed that too many borehole heat exchangers is wasteful and uneconomical, and, therefore, a numerical solution is necessary. In the process of numerical simulation, the selection of model parameters is particularly important.…”

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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“…Zhang [21] and Molina-Giraldo et al [22] studied the effect of simultaneously considering permafrost in the soil, groundwater seepage, and heat transfer through the water pipe of an energy pile and found that increasing the distance between the energy piles reduced the heat transfer effect of the piles but improved year-round performance. Antelmi [23] and Jia et al [24] investigated the effects of groundwater seepage on heat exchange in energy piles and found that flowing groundwater was conducive to soil temperature recovery and the heat exchange of an energy pile.…”

Section: Introductionmentioning

confidence: 99%

Effect of Different Control Strategies on the Heat Transfer Mechanism of Helical Energy Piles

Wei,

Li,

et al. 2024

Applied Sciences

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In this paper, numerical simulations of a special energy pile, which constitutes a spiral-injected pipe and one straight discharge pile for Geothermal Heat Pump Systems (SGHEs-P(parallel)), were conducted by Fluent software. The effects of the spiral pitches on the heat transfer rate based on the G-function method and peripheral soil temperature of the pile were investigated under continuous and intermittent operation strategies. The impact of spiral tube sizing on the surface heat transfer coefficients was studied. The results indicated that SGHEs-P may be preferred for office buildings under intermittent operation conditions. For a short period, the temperature profiles and heat transfer efficiency of SGHEs-P were mainly influenced by the fluid type, length of the spiral tube, and spiral pitch. The smaller the spiral pitch, the more uniform the temperature distribution, and the better the heat transfer effect, but the heat transfer per unit depth of pile decreased. The average temperature variation curve of the soil around the energy pile with different spiral pitches was simulated and obtained over time. Meanwhile, the impact of spiral radius, spiral pitch, and spiral tube radius on the convective heat transfer coefficient was also presented. Through data fitting, the formulas for the correction coefficients of spiral radius, spiral pitch, and spiral tube radius on convective heat transfer coefficient were obtained, respectively.

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A New Type in TRNSYS 18 for Simulation of Borehole Heat Exchangers Affected by Different Groundwater Flow Velocities

Cited by 11 publications

References 26 publications

Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

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

Effect of Different Control Strategies on the Heat Transfer Mechanism of Helical Energy Piles

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