Evaluation of Analytical and Numerical Techniques for Defining the Radius of Influence for an Open-Loop Ground Source Heat Pump System

Freedman, Vicky L.; Mackley, Rob D.; Waichler, Scott R.; Horner, Jacob A.

doi:10.1061/(asce)he.1943-5584.0000720

Cited by 5 publications

(3 citation statements)

References 19 publications

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“…In the open-loop configuration, the system is directly utilizing the groundwater for the heat exchange. 20,21 The configuration requires an adequate source of relatively clean groundwater. Otherwise, the system application will be unfeasible.…”

Section: Introductionmentioning

confidence: 99%

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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%

“…GCHE could be classified into two main categories: open‐loop and closed‐loop heat exchangers. In the open‐loop configuration, the system is directly utilizing the groundwater for the heat exchange 20,21 . The configuration requires an adequate source of relatively clean groundwater.…”

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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“…Studies without the assumption of axial symmetry exist, but are rare and do not focus on the zone of influence. Some examples are Young (1989), where isobars within a cross-section plane of an arbitrary set of vertical landfill wells demonstrate the asymmetric flow field; and Freedman et al (2013), where the fluid is incompressible and hydraulic pressure contours are shown to break azimuthal symmetry. A distinct type of work pursues the identification of preferential flow directions based on the structure of the porous matrix (Mauran et al 2001.…”

Section: Introductionmentioning

confidence: 99%

Singularities in weakly compressible flow through a porous medium

Nec¹

2021

Fluid Dyn. Res.

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The flow of weakly compressible fluid in an annular domain filled with a porous medium admits a wide class of solutions, whose axial symmetry is broken by azimuthally varying permeability. The structural parameters governing the underpinning dynamical system are the angles of sectors containing media of distinct permeability and values of the permeabilities themselves. Albeit from the vantage point of physics there is no apparent reason that certain configurations be singled out, mathematical analysis reveals an intriguingly complex pattern of singularities. The singular manifolds are loci, in whose vicinity saddle points of the underlying pressure field shift abruptly or appear/disappear. Stunningly the shift angle is independent of all configuration parameters, equalling π/2. When the system represents an injection or extraction well, the distance of the saddle points therefrom assumes the physical interpretation of the well's reach, also known as the radius of influence. Therefore two infinitesimally close configurations might have disparate flow fields and in particular zones of influence. This analysis casts in a new light the baffling difficulties encountered in the construction of aquifer sparging wells and landfill or natural gas collection wells, whose reach is known to be poorly predictable, and the failure or success of the injection/suction to induce the motion of adequate amounts of fluid proved moot. The traditional concept of the radius of influence is shown to be ill-posed and its unpredictability in practice intimately connected to the structural singularities of the anisotropic porous medium.

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