Improvement of borehole thermal energy storage design based on experimental and modelling results

Lanini, Sandra; Delaleux, Fabien; Py, Xavier; Olivès, Régis; Nguyen, Denis

doi:10.1016/j.enbuild.2014.03.056

Cited by 48 publications

(24 citation statements)

References 12 publications

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“…1) and was also discussed by Heller et al (2014). Nonetheless, repurposing in this manner of individual deep boreholes might seem contrary to the point stated above, that for optimal efficiency BTES boreholes should be arranged in 'fields' rather than in isolation (Lanini et al 2014). However, as will become clear, since the ambient temperature at ~2-3 km depths is many tens of °C 45 higher than at the Earth's surface, BTES at such depths can be managed to balance storage and extraction of heat about this ambient temperature, rather than involving net heat injection, only part of which is recovered.…”

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confidence: 75%

“…This point, which does not seem to have been taken on board by advocates of the 'DGSW' concept in Fig. 9, can be regarded as the 'heat extraction' analogue of the result (Lanini et al 2014) that to optimise heat storage a BTES borehole array should be broad, to minimise heat losses into the 40 surroundings. It means that, although high rates of thermal output might be obtained in the short term, a borehole heat exchanger like that in Fig.…”

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confidence: 99%

“…It is also partly a consequence of the thermal diffusivity of Carboniferous mudstones in Britain being 20 assumed to be higher than the typical measured value (from Mielke et al 2014) for the rocks utilized for the Crailsheim subsurface heat exchanger. An additional factor, recently recognized (Lanini et al 2014), is that the design of this project was non-optimal from the point of view of efficiency of energy storage. It has indeed been reported (Lanini et al 2014) that the most efficient design for such projects, to minimize radial heat losses to the surroundings, requires the form factor of the borehole 25 field, the ratio of its diameter to its vertical extent, to be 2, whereas for the Crailsheim project this ratio was ~28 m / ~55 m or ~0.5.…”

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confidence: 99%

“…Lamarche & Beauchamp, 2007;Li et al 2014;Choi & Ooka 2015;Xiong et al 2015) and considerations of optimum system design (e.g. Lanini et al 2014). As regards the latter issue, Lanini et al (2014) showed that, to minimize radial heat losses into the surroundings, the optimum 10 BTES design involves the construction of 'fields' of borehole heat exchangers (rather than single vertical boreholes), arranged such that the diameter of the 'field' is double the vertical extent of the boreholes.…”

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confidence: 99%

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Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues

Westaway

2016

QJEGH

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Westaway, R. (2016) Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues. Quarterly Journal of Engineering Geology and Hydrogeology, 49, pp. 213-227. (doi:10.1144/qjegh2016-016) This is the author's final accepted version.There may be differences between this version and the published version. Abstract: Development of many wells is envisaged in the UK in coming decades to exploit the abundant shale gas resource as fuel and petrochemical feedstock. Forward planning is therefore warranted regarding reuse of the resulting subsurface infrastructure after gas production has 10 ceased. It is shown that this infrastructure might be repurposed for Borehole Thermal Energy Storage (BTES). Preliminary calculations, assuming an idealized cycle of summer heat storage and winter heat extraction, indeed demonstrate annual storage of ~6 TJ or ~2 GWh of energy per BTES well. Summed over the anticipated well inventory, a significant proportion of the UK's future heat demand might thus be supplied. This form of BTES technology has particular 15 relevance to the UK, where the shale resource is located in relatively densely populated areas; it is especially significant for Scotland, where the resource coincides with a particularly high proportion of the population and heat demand.

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Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues

Westaway

2016

QJEGH

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“…The results provided a good insight for the design of their heat exchanger. Lanini & al (2014) investigated a 3D numerical model to simulate different type of U-tube borehole energy storage system. Their results were validated according to experimental data and numerical results.…”

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Assessment of Heat Recovery and Recovery Efficiency of a Seasonal Thermal Energy Storage System in a Moist Porous Medium

Dada¹,

Benchatti²

2016

IJHT

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Thermal energy storage has received a great interest by researchers and industrials as part of designing new systems able to store and deliver thermal energy efficiently for long periods, especially in regions characterized by important solar energy potential. The aim of this preliminary work is to simulate the performance of a novel seasonal heat storage system dedicated to store heat in the ground during hot period then to recover it during cold period. The system investigated herein is a ground heat exchanger buried at only 8 m below the underground while other technologies go deeper than 100 m. Several case studies have been simulated according to different types of hot fluid carrier and moisture content of the porous medium. Comsol Multiphysics was used to model heat exchange between a fluid carrier flowing through a GHX, and a partially saturated porous medium composed essentially of gravel and located at about 0.5 m underground. Performance of the system was evaluated for a one-year period in order to get a good estimation of long-term heat storage and recovery. The results showed that the use of gasoline as a fluid carrier will yield higher temperature levels than the other fluids particularly during cold season; however, the use of water allowed for the storage and recovery of bigger heat energy than gasoline or glycol do. However, moisture content of the porous medium did not influence the whole process. System heat recovery has been enhanced by the use of two ducts to extract more heat from the underground. This approach led to a remarkable increase in temperature levels, as well as heat energy and recovery efficiency which went up from 41% when using only 1 duct to 71%.

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Numerical and analytical study of a geo‐exchange borehole using conventional grout and bentonite‐based backfilling material

Bayomy

Wang²,

Dworkin

2021

Int J Energy Res

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Ground source heat pumps (GSHP) have been used in various types of residential and commercial buildings due to their high efficiency. Numerical models are useful to predict the overall performance and ground temperature response of these systems. This paper presents a hybrid model that contains a modified finite element model and an analytical solution for a single conventional vertical borehole system. In this modified finite element model, turbulent heat transfer equations were solved for the ground heat exchanger and the actual building load variation and heat pump performance variation were considered. The present model was then used to explore an emerging geo-exchange technology, which involves the use of a bentonite slurry enhanced with graphite flakes in the vicinity of a borehole heat exchanger. The results revealed slight increases in the mean average ground temperature in the vicinity of the borehole by 1.1 C over 4 years. Furthermore, the analytical solution of the ground temperature response was in good agreement with the results obtained using the finite element model within a maximum relative error of 3% (0.5 C). The results revealed that the 40 m depth bentonite-based borehole achieved better performance than the conventional design by 5% to 13% in the monthly average COP.

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Improvement of borehole thermal energy storage design based on experimental and modelling results

Cited by 48 publications

References 12 publications

Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues

Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues

Assessment of Heat Recovery and Recovery Efficiency of a Seasonal Thermal Energy Storage System in a Moist Porous Medium

Numerical and analytical study of a geo‐exchange borehole using conventional grout and bentonite‐based backfilling material

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