New Insights into Heat Transfer of Deep Coaxial Geothermal Heat Exchangers DOI

Shurun Wang,

Xianhua Deng,

Youjian Wu

et al.

Published: Jan. 1, 2023

Deep geothermal heat exchangers (DGHEs) have emerged as a potential approach to exploiting energy stable high-temperature source for ground-coupled pumps. This study aimed offer insights into the transfer of DGHEs by systematic numerical simulations. first created finite-volume model (FVM) DGHEs, which uses governing equations circulating fluid inside borehole time-varying boundary condition wall. The FVM was verified comparison with several reported models. analysis emphasized validity homogeneous-medium assumption about ground and characteristics flux on seems be only acceptable in cases limited thermal conductivity differences between layers (e.g., < 2.0 W/m·K). Not wall varies linearly depth, but slope interception line are linear functions logarithm time.

Language: Английский

Comparison of the thermal and hydraulic performance of single U-tube, double U-tube and coaxial medium-to-deep borehole heat exchangers DOI Creative Commons
Christopher S. Brown, Isa Kolo, David Banks

et al.

Geothermics, Journal Year: 2023, Volume and Issue: 117, P. 102888 - 102888

Published: Dec. 7, 2023

Decarbonisation of heat is essential in curbing carbon dioxide emissions and can be achieved through the use geothermal systems. Recently, single-well, closed-loop, deep borehole exchangers, using a coaxial design, have become focus attention, partly due to potential repurpose existing infrastructure (such as oil gas wells); however, few investigated for other types exchanger middle-deep Therefore, this study, comprehensive numerical analysis was undertaken OpenGeoSys software investigate thermal hydraulic performance coaxial, single U-tube double exchangers (MDBHEs). The purpose paper test maximum operational depth each type pipe configuration wells been completed depths exceeding 500 m single/double configurations. best performing MDBHEs should minimise parasitic losses, whilst maximising output. Furthermore, ground sourced pumps require electricity; therefore, at times where electricity prices are high (and drilling costs minimised) it may more beneficial utilise encounter greater temperatures. Results indicate that provide terms specific extraction lowest pressure/parasitic losses. Double similar but significantly pressure losses across all simulations, which translates pumping power costs. Single demonstrate poorest At end 25-year base case scenario 800 MDBHE, configurations, with fluid circulation rate 5 L/s, provided rates 39.1 W/m, 32.8 36.0 respectively, inlet temperature set constant °C. For these were estimated 85 kPa (coaxial), 1.46 MPa (single U-tube) 423 (double U-tube)—the value being close nominal 16 bar (1.6 Mpa) rating SDR11 density polyethylene pipe. Further parametric also undertaken, investigating depth, flow rate, rock conductivity, diameter shank spacing.

Language: Английский

Citations

33
Investigating the Influence of Groundwater Flow and Charge Cycle Duration on Deep Borehole Heat Exchangers for Heat Extraction and Borehole Thermal Energy Storage DOI Creative Commons
Christopher S. Brown, Hannah Rose Doran, Isa Kolo

et al.

Energies, Journal Year: 2023, Volume and Issue: 16(6), P. 2677 - 2677

Published: March 13, 2023

Decarbonisation of heat is essential to meeting net zero carbon targets; however, fluctuating renewable resources, such as wind or solar, may not meet peak periods demand. Therefore, methods underground thermal energy storage can aid in storing low demand be exploited when required. Borehole (BTES) an important technology surplus and the efficiency systems strongly influenced by groundwater flow. In this paper, effect flow on a single deep borehole exchanger (DBHEs) was modelled using OpenGeoSys (OGS) software test impact varying regional Darcy velocities performance extraction BTES. It anticipated that infrastructure ex-geothermal exploration oil gas development wells approaching end life could repurposed. These encounter fluid subsurface well BTES has previously been investigated. Higher increase DBHE operating extract only for heating season 6 months. This due reduced cooling rocks proximity replenishes which removed from rock volume around (this also equivalently thought “coolth” being transported away plume). When testing with other parameters 920 m length conductivity 2.55 W/(m·K), it observed larger velocity (1e-6 m/s) output up 28 kW comparison there no contrast, inhibits depletes store, reducing 13% models advective transfer subsurface. The highest 1e-6 m/s shown most influence BTES; likelihood occurring regionally, at depth over 1 km unlikely. study tested temporal resolutions charge cyclicity. Shorter allow greater recovery (c. 34% injected recovered month charge, opposed <17% months charge).

Language: Английский

Citations

27
A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications DOI Creative Commons
Isa Kolo, Christopher S. Brown,

William Nibbs

et al.

Geothermal Energy, Journal Year: 2024, Volume and Issue: 12(1)

Published: June 10, 2024

Language: Английский

Citations

14
Assessing the technical potential for underground thermal energy storage in the UK DOI Creative Commons
Christopher S. Brown, Isa Kolo, Andrew Lyden

et al.

Renewable and Sustainable Energy Reviews, Journal Year: 2024, Volume and Issue: 199, P. 114545 - 114545

Published: May 14, 2024

Heating and cooling both make up a large part of the total energy demand in UK; long-term seasonal thermal storage (STES) can address temporal imbalances between varying supply heat to buildings processes. Underground (UTES) play role decarbonisation by storing waste from space cooling, refrigeration, data processing, industrial processes, harvested summer solar or even generated surplus renewable (solar wind) electricity with fluctuating supply. This paper evaluates range UTES technologies UK context addresses geological suitability, capacity, low-carbon sources, surface sources demand. review concludes that there is significant potential for aquifer (ATES) borehole (BTES) systems, coinciding Therefore, uptake technology will help achieve net-zero carbon neutral targets 2050. There also scope utilise within existing subsurface infrastructure. are 464 oil gas wells which could be repurposed upon end life using different technologies. However, repurposing needs further evaluation; deep single well BTES systems have high area volume ratio storage, reducing efficiency such ATES limited issues associated contaminants. 23,000 abandoned mines underlay ∼25 % UKs population utilised minewater (MTES).

Language: Английский

Citations

10
Unlocking deep geothermal energy in the UK using borehole heat exchangers DOI Creative Commons
Christopher S. Brown, Louis Howell

Geology Today, Journal Year: 2023, Volume and Issue: 39(2), P. 67 - 71

Published: March 1, 2023

In the wake of COP 26, international community is aiming to reduce carbon emissions by adopting alternative and renewable energy sources. Deep geothermal can help achieve this as it represents a low carbon‐emitting resource that provide constant base load energy. United Kingdom, development deep has been limited due high geological uncertainty risk. Past exploration focused on hot sedimentary aquifers dry‐rock granites, with success. To mitigate risk extract heat lower reliance properties, such permeability, new methods have conceived using borehole exchangers, where fluid circulated in closed‐loop system. Feasibility studies undertaken through modelling exchangers hope these novel technologies be used exploit

Language: Английский

Citations

14
Numerical investigation on the long-term heating performance and sustainability analysis of medium-deep U-type borehole heat exchanger system DOI
Shuai Huang, Jiqin Li, Ke Zhu

et al.

Energy, Journal Year: 2023, Volume and Issue: 289, P. 129955 - 129955

Published: Dec. 14, 2023

Language: Английский

Citations

14
Investigating heat transmission in a wellbore for Low-Temperature, Open-Loop geothermal systems DOI Creative Commons
Christopher S. Brown, Gioia Falcone

Thermal Science and Engineering Progress, Journal Year: 2023, Volume and Issue: 48, P. 102352 - 102352

Published: Dec. 22, 2023

Heat transfer processes in geothermal wellbores are an essential component to overall system performance, but can be overlooked subsurface modelling studies that tend focus on reservoir response. This study addresses heat the wellbore through a comprehensive of 10 different parameters OpenGeoSys software designed evaluate losses during open-loop production conditions for typical low-temperature (<100 °C) single phase systems. Models were set-up effects only, using well with constant fluid inlet temperature boundary condition. Results indicate under base case 2-km deep surrounded by rock formations thermal conductivity 2.5 W/(m.K) and bottom-hole 60 °C, difference (reservoir) (wellhead) at end 40-year period is 2.06 °C. corresponds minimum into surrounding -63.3 W/m, which ∼7 % power recorded wellhead (assuming rejection 30 3.4 temperature. These significant, particularly when combination surface exchanger or breakthrough. Wellbore insulation reduce losses, it would appear this only impacts short-term. performance also improved, minimized, developing wells above interval low high gradients.

Language: Английский

Citations

11
Surface–subsurface modelling of seasonal borehole thermal energy storage for a university building DOI Creative Commons
Isa Kolo, Christopher S. Brown, Sean Watson

et al.

Journal of Energy Storage, Journal Year: 2025, Volume and Issue: 113, P. 115598 - 115598

Published: Feb. 7, 2025

Language: Английский

Citations

0
A perspective on Paul Younger’s work on the Newcastle Science Central Deep Geothermal Borehole and new developments from the NetZero GeoRDIE project DOI Creative Commons
Christopher S. Brown, Isa Kolo, Gioia Falcone

et al.

Published: Feb. 14, 2025

Paul Younger, to whose memory this issue is dedicated, was an early advocate of a geothermal energy renaissance in the north England. This paper offers background experience gained with Eastgate BH1 and BH2B boreholes, focused on exploring potential Weardale Granite, followed by what has subsequently become known as Newcastle Science Central Deep Geothermal Borehole (NSCDGB), which found sequence (presumed) Fell Sandstones. These efforts represent not only legacy piece infrastructure UK, but also Younger. While NSCDGB been developed using conventional methods, it proved invaluable providing data modelling test-bed for northern England hoped that future years can serve testing facility deep research. Research carried out part recently concluded NetZero GeoRDIE confirmed could still be converted Heat Exchanger (DBHE), indicative total continuous heat yield >50 kW lifetime 25 if repurposed c.920 m depth.

Language: Английский

Citations

0
Polynomial chaos-based uncertainty quantification of the performance of a closed loop deep geothermal borehole DOI Creative Commons
T.S. Charlton, Mohamed Rouainia

Geothermics, Journal Year: 2025, Volume and Issue: 129, P. 103271 - 103271

Published: Feb. 21, 2025

Language: Английский

Citations

0