A hybrid numerical-semi-analytical method for computer simulations of groundwater flow and heat transfer in geothermal borehole fields

Cimmino, Massimo; Baliga, B. R.

doi:10.1016/j.ijthermalsci.2019.04.012

Cited by 17 publications

(6 citation statements)

References 61 publications

(86 reference statements)

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“…With these results, the use of methods such as thermal resistance capacitance (TRC) methods should be revisited when including groundwater flow, as the delta-circuit is not always valid. Extending the method from 2D to 3D including thermal interactions between boreholes and time-dependent fluid temperatures could be done using a segmented MFLS solution (Cimmino and Baliga, 2019) and a modified equivalent borehole method (Prieto and Cimmino, 2021b) with a coefficient updating scheme as done in Cimmino (2021a, 2022).…”

Section: Discussionmentioning

confidence: 99%

Transient heat transfer in ground heat exchangers under groundwater flow

Prieto¹,

Cimmino²

2022

Proceedings of the IGSHPA Research Track 2022

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An analytical solution for the transient heat transfer under groundwater flow for ground heat exchangers (GHEs) is presented. The method is an extension of the transient multipole expansion that describes the transient heat transfer as a pure conduction phenomenon inside and around a GHE including arbitrarily positioned pipes in the grout, coupling an irrotational and incompressible potential field in the ground with constant far-field velocity. The method does not rely on the supposition that groundwater flows through the GHE but instead moves around it. The method is validated against a finite element analysis model comparing the borehole wall temperature for two cases considering different single U-tube pipes position. It is shown that the thermal resistances inside the GHE do not respect the general symmetry condition (𝑅 ≠ 𝑅 and 𝑅 ≠ 𝑅 ) as opposed to the pure conduction problem.

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Section: Discussionmentioning

confidence: 99%

Transient heat transfer in ground heat exchangers under groundwater flow

Prieto¹,

Cimmino²

2022

Proceedings of the IGSHPA Research Track 2022

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“…The modules were presented in an earlier publication (Cimmino, 2018b), except for the networks and media modules introduced in versions 1.1.1 and 2.0, respectively. The networks module enables the configuration of piping connections between boreholes and the evaluation of 𝑔-functions for mixed parallel and series connections between boreholes (Cimmino, 2019), including fields of coaxial boreholes since version 2.1. The media module gives access to fluid properties using CoolProp (Bell et al, 2014).…”

Section: New Features and Changes To Existing Modulesmentioning

confidence: 99%

“…The gfunction module was refactored to replace the dedicated functions for different boundary conditions by a single class that can handle all calculation options. pygfunction supports 3 boundary conditions: uniform and equal heat extraction rates , uniform and equal borehole wall temperatures , and mixed inlet fluid temperatures (Cimmino, 2019). When computing 𝑔-functions, a user might use a combination of the boreholes, pipes, networks and media modules to define the borefield, depending on the chosen boundary condition, and use the gfunction module to evaluate the 𝑔-functions.…”

Section: New Features and Changes To Existing Modulesmentioning

confidence: 99%

“…proposed to axially discretize each borehole into segments and superimpose the FLS solution in both space and time to reproduce Eskilson's uniform borehole wall temperature boundary condition. Their method was later extended to inclined boreholes (Lazzarotto, 2016), and to more detailed boundary conditions accounting for the heat transfer between the fluid and the borehole wall (Cimmino, 2015(Cimmino, , 2019. Although not presented here, there is ongoing research on the development of analytical solutions and 𝑔-functions for fields of boreholes with groundwater advection and depth-dependent ground properties.…”

Section: Introductionmentioning

confidence: 99%

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Proceedings of the IGSHPA Research Track 2022

2022

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This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doepublic-access-plan).

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“…Another type of hybrid model couples analytical solution with numerical algorithm. Recently, Cimmino and Baliga [32] developed a relatively cost-effective hybrid method for vertical BHEs along with groundwater flow, where the numerical results from a co-located FEM and finite volume method were marched with thermal resistance models. The hybrid approach can also march two spatial dimensions (so-called "1+1D algorithm") to greatly increase the computational efficiency compared with solving a full-scale model.…”

Section: Introductionmentioning

confidence: 99%

An Analytical Model for Transient Heat Transfer with a Time-Dependent Boundary in Solar- and Waste-Heat-Assisted Geothermal Borehole Systems: From Single to Multiple Boreholes

Hefni

Hassani

et al. 2021

Applied Sciences

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With the increasing engineering applications of geothermal borehole heat exchangers (BHEs), accurate and reliable mathematical models can help advance their thermal design and operations. In this study, an analytical model with a time-dependent heat flux boundary condition on the borehole wall is developed, capable of predicting the thermal performance of single, double, and multiple closed-loop BHEs, with an emphasis on solar- and waste-heat-assisted geothermal borehole systems (S-GBS and W-GBS) for energy storage. This analytical framework begins with a one-dimensional transient heat conduction problem subjected to a time-dependent heat flux for a single borehole. The single borehole scenario is then extended to multiple boreholes by exploiting lines of symmetry (or thermal superposition). A final expression of the temperature distribution along the center line is attained for single, double, and multiple boreholes, which is verified with a two-dimensional finite-element numerical model (less than 0.7% mean absolute deviation) and uses much lesser computational power and time. The analytical solution is also validated against a field-scale experiment from the literature regarding the borehole and ground temperatures at different time frames, with an absolute error below 6.3%. Further, the thermal performance of S-GBS and W-GBS is compared for a 3-by-3 borehole configuration using the analytical model to ensure its versatility in thermal energy storage. It is concluded that our proposed analytical framework can rapidly evaluate closed-loop geothermal BHEs, regardless of the numbers of boreholes and the type of the heat flux on the borehole wall.

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A hybrid numerical-semi-analytical method for computer simulations of groundwater flow and heat transfer in geothermal borehole fields

Cited by 17 publications

References 61 publications

Transient heat transfer in ground heat exchangers under groundwater flow

Transient heat transfer in ground heat exchangers under groundwater flow

Proceedings of the IGSHPA Research Track 2022

An Analytical Model for Transient Heat Transfer with a Time-Dependent Boundary in Solar- and Waste-Heat-Assisted Geothermal Borehole Systems: From Single to Multiple Boreholes

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