High-temperature heat storage in geological media: high-resolution simulation of near-borehole processes

Boockmeyer, Anke; Bauer, Sebastian

doi:10.1680/geolett.13.00060

Cited by 21 publications

(4 citation statements)

References 17 publications

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“…The third method is computationally very expensive for 3D simulations but requires no special implementation and can therefore be set up in any general-purpose code like ANSYS/Fluent , TOUGH2 (Doran et al 2021) and COMSOL (Hu et al 2020;Janiszewski et al 2018;Villa 2020). Besides the DBHE model implemented using the dual-continuum method in OGS (Shao et al 2016;Hein et al 2016;Chen et al 2019Chen et al , 2021, a fully discretised FEM model developed using OGS was also used by Boockmeyer and Bauer (2014) which allows a direct comparison between both approaches. Other specialised software packages such as FEFLOW (Diersch 2013;Le Lous et al 2015;Rapantova et al 2016) also have capabilities for both approaches.…”

Section: Numericalmentioning

confidence: 99%

A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications

Kolo,

Brown,

Nibbs

et al. 2024

Geotherm Energy

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Deep borehole heat exchangers (DBHEs) with depths exceeding 500 m have been researched comprehensively in the literature, focusing on both applications and subsurface modelling. This review focuses on conventional (vertical) DBHEs and provides a critical literature survey to analyse (i) methodologies for modelling; (ii) results from heat extraction modelling; (iii) results from modelling deep borehole thermal energy storage; (iv) results from heating and cooling models; and (v) real case studies. Numerical models generally compare well to analytical models whilst maintaining more flexibility, but often with increased computational resources. Whilst in-situ geological parameters cannot be readily modified without resorting to well stimulation techniques (e.g. hydraulic or chemical stimulation), engineering system parameters (such as mass flow rate of the heat transfer fluid) can be optimised to increase thermal yield and overall system performance, and minimise pressure drops. In this active research area, gaps remain, such as limited detailed studies into the effects of geological heterogeneity on heat extraction. Other less studied areas include: DBHE arrays, boundary conditions and modes of operation. A small number of studies have been conducted to investigate the potential for deep borehole thermal energy storage (BTES) and an overview of storage efficiency metrics is provided herein to bring consistency to the reporting of thermal energy storage performance of such systems. The modifications required to accommodate cooling loads are also presented. Finally, the active field of DBHE research is generating a growing number of case studies, particularly in areas with low-cost drilling supply chains or abandoned hydrocarbon or geothermal wells suitable for repurposing. Existing and planned projects are thus presented for conventional (vertical) DBHEs. Despite growing interest in this area of research, further work is needed to explore DBHE systems for cooling and thermal energy storage.

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Section: Numericalmentioning

confidence: 99%

A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications

Kolo,

Brown,

Nibbs

et al. 2024

Geotherm Energy

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“…In Germany, this transition from fossil to renewable energy sources, termed ''Energiewende'', is further accelerated by the phase out of nuclear energy until 2022. (BMWi 2010) and 80% of the final electricity consumption (Jain et al 2015) by renewable energies by the year 2050. In 2014, the production of renewable energies in Germany reached 13.5% of the final energy consumption and 27.4% of the final electricity consumption (BMWi 2015).…”

Section: Introductionmentioning

confidence: 99%

Energy storage in the geological subsurface: dimensioning, risk analysis and spatial planning: the ANGUS+ project

et al. 2016

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New techniques and methods for energy storage are required for the transition to a renewable power supply, termed ''Energiewende'' in Germany. Energy storage in the geological subsurface provides large potential capacities to bridge temporal gaps between periods of production of solar or wind power and consumer demand and may also help to relieve the power grids. Storage options include storage of synthetic methane, hydrogen or compressed air in salt caverns or porous formations as well as heat storage in porous formations. In the ANGUS? project, heat and gas storage in porous media and salt caverns and aspects of their use on subsurface spatial planning concepts are investigated. The optimal dimensioning of storage sites, the achievable charging and discharging rates and the effective storage capacity as well as the induced thermal, hydraulic, mechanical, geochemical and microbial effects are studied. The geological structures, the surface energy infrastructure and the governing processes are parameterized, using either literature data or own experimental studies. Numerical modeling tools are developed for the simulation of realistically defined synthetic storage scenarios. The feasible dimensioning of storage applications is assessed in sitespecific numerical scenario analyses, and the related spatial extents and time scales of induced effects connected with the respective storage application are quantified. Additionally, geophysical monitoring methods, which allow for a better spatial resolution of the storage operation, induced effects or leakages, are evaluated based on these scenario simulations. Methods for the assessment of such subsurface geological storage sites are thus developed, which account for the spatial extension of the subsurface operation itself as well as its induced effects and the spatial requirements of adequate monitoring methods.

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“…They can be used for simulation of either largescale applications or for thermal response tests in complex geologic settings (e.g. Kohl et al 2002;Signorelli et al 2007;Marcotte and Pasquier 2008;Wagner et al 2012;Boockmeyer and Bauer 2014). These models require a fine discretisation, especially inside the BHE with the small given geometry of the U-tubes or coaxial pipes, the pipe interiors and the grout, but also in the aquifer close to the BHE.…”

Section: Introductionmentioning

confidence: 99%

Efficient simulation of multiple borehole heat exchanger storage sites

Boockmeyer

Bauer

2016

Environ Earth Sci

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In this paper, an adapted model is developed for borehole heat exchangers (BHEs) to simulate geothermal applications such as heat storage on a large scale efficiently and with high accuracy. The adapted numerical model represents all BHE components, allowing for a detailed representation of the governing processes. The approach is calibrated and validated for a single U-tube BHE using a high-resolution experimental data set from a laboratory thermal response test. It is found that the computational effort can be reduced by factors of *50, *50 and *25 for single U-tube, double U-tube and coaxial BHEs, respectively, if an absolute deviation of less than 1 % compared to a conventional fully discretised model is allowed. Computation times can be reduced further by accepting higher deviations. The adapted modelling approach allows for a detailed and correct representation of the temporal and spatial temperature distribution under highly transient conditions by applying it to a high-temperature heat storage scenario using multiple BHEs. The model is especially suited to represent coupled flow and heat transport processes, to account for groundwater flow in the BHE region as well as geological heterogeneities and especially interaction between a large number of BHEs.Keywords Borehole thermal energy storage Á Borehole heat exchanger Á Numerical simulation Á Fully discretised models Á OpenGeoSys List of symbols aSolid compressibility (Pa -1 ) bFluid compressibility (Pa -1 ) cq Volumetric heat capacity (J m -3 K -1 ) dThickness (m) D Heat diffusion dispersion tensor g Gravitational acceleration (m s -1 ) k Intrinsic permeability (m) L Length (m) m Side length (m) n Porosity (-) p Pressure (Pa) Q Sources and sinks (kg m -3 s -1 ) Q H Heat sources and sinks (W m -3 ) rRadius (m) R th Thermal resistance (K W -1 )Transport velocity (m s -1 ) z Depth (m) a Dispersivity (m) kThermal conductivity (W m -1 K -1 ) l Fluid dynamic viscosity (N s m -2 ) q Density (kg m -3 )

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High-temperature heat storage in geological media: high-resolution simulation of near-borehole processes

Cited by 21 publications

References 17 publications

A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications

A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications

Energy storage in the geological subsurface: dimensioning, risk analysis and spatial planning: the ANGUS+ project

Efficient simulation of multiple borehole heat exchanger storage sites

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