A novel solution for vertical borehole heat exchangers in multilayered ground with the Robin boundary condition

Applied Thermal Engineering, Journal Year: 2024, Volume and Issue: 255, P. 123923 - 123923

Published: July 14, 2024

The ground surface condition is crucial in the thermal analysis of borehole heat exchange (BHE) systems, as it directly influences regime within subsurface. However, most existing analytical solutions assume a constant temperature at equal to undisturbed temperature, overlooking impact various anthropogenic and environmental factors that alter conditions. This study addresses this gap by proposing new semi-analytical solution incorporates Robin boundary for BHEs multilayered ground. solution, developed using unsteady element method, balances computational efficiency with precision. proposed was verified an exact homogeneous body, showing maximum error approximately 0.2 %. Compared prescribing surface, better captures between surrounding environment. results show variations transfer coefficient can cause differences mean wall change up 7.45 % over about 31.7 years (109 s) 70-metre borehole. Meanwhile, unit flux raise 0.56 °C 0.25 Wm−2K−1 years. Additionally, circulating fluid transmit greater depths. indicate even bottom borehole, fixed underestimate 6.11 compared condition. These findings emphasize indispensability accurately predicting performance BHEs.

Language: Английский

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Finding common ground: A methodology for city-scale subsurface thermal modelling

Urban Climate, Journal Year: 2023, Volume and Issue: 49, P. 101513 - 101513

Published: April 2, 2023

Language: Английский

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Modeling underground climate change across a city based on data about a building block

Sustainable Cities and Society, Journal Year: 2024, Volume and Issue: 114, P. 105775 - 105775

Published: Aug. 26, 2024

Language: Английский

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Open questions about the effects of ground warming on infrastructure

Nature Cities, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 25, 2024

Language: Английский

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Thermal interactions among vertical geothermal borehole fields

Renewable Energy, Journal Year: 2022, Volume and Issue: 194, P. 1204 - 1220

Published: May 31, 2022

Language: Английский

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Geothermal pavements: A city-scale investigation on providing sustainable heating for the city of Cardiff, UK

Renewable Energy, Journal Year: 2023, Volume and Issue: 218, P. 119248 - 119248

Published: Sept. 4, 2023

Geothermal pavements can be used with ground-source heat pump systems to sustainably provide energy for heating and cooling by incorporating ground exchanger elements underneath pavement surfaces. This work investigates the suitability of geothermal at scale, adopting city Cardiff, UK, as a case-study. A two-scale modelling framework, combining detailed small-scale holistic large-scale approaches, is presented, accuracy former continuity latter. The results show that between 184 kWh 345 thermal per metre length supplied annually, depending on soil profile. Moreover, operation reduce anthropogenic flux into from heated basements, its associated negative impacts, about 390 MWh/year. city-scale analysis using population-consistent geographic areas called LSOAs, estimates supply 23% entire residential demand, or up 75% sharing LSOAs. larger LSOAs highlighted, supplying 100% annual domestic demand. Investigating carbon emissions technologies shows potential reductions when replacing gas boilers resistance systems.

Language: Английский

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A city-wide investigation on the subsurface temperature evolution and geothermal capacity evaluation

Journal of Rock Mechanics and Geotechnical Engineering, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 1, 2024

Language: Английский

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Influence of Buildings on the Subsurface Thermal Field of the City of Yekaterinburg

Izvestiya Atmospheric and Oceanic Physics, Journal Year: 2024, Volume and Issue: 60(8), P. 884 - 895

Published: Dec. 1, 2024

Language: Английский

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Deformations caused by subsurface heat islands: a study on the Chicago Loop

Symposium on Energy Geotechnics 2023, Journal Year: 2023, Volume and Issue: unknown

Published: Sept. 28, 2023

The ground beneath urban areas is warming up due to anthropogenic activity, leading subsurface heat islands [1]. A recent review of the literature suggests that are causing an increase in average temperature between 0.1 2.5°C per decade down 100 m depth various cities across world [2]. Studies highlight multiple impacts rises on areas. Subsurface can affect biochemical state [e.g., 3] and hydrogeological 4] underground, shifts plant growth thermal pollution groundwaters, among other issues. also cause transportation infrastructure public health issues, such as overheated subway rails force trains slow or stop avoid incidents, extreme air temperatures underground induced diseases 5,6]. Meanwhile, represent opportunity, geothermal technologies harness reutilize additional from 7,8]. Motivated by lack a fundamental understanding performance civil infrastructure, this study addresses knowledge gap validates its underlying hypothesis with reference real case study: Chicago Loop district – densest US after Manhattan, which suffers island Two facilities used explore complex problem: 3-D computer model wireless sensing network installed surface environments district. developed reproduces morphology account building basements, parking garages, tunnels, train stations characterize district. Based substantial amount data gathered these built surface, allows for simulation waste continuously injected into studied area. employed approach consists 3-D, time-dependent, thermo-hydro-mechanical finite element modeling, not only quantify variations space time but their effects deformation groundwater flow. Simulations performed over years: 1951, when tunnels were completed approached current state, till 2051. results provide values match collected heart Loop’s (Figure 1). On one hand, evidence retrieving evolution field 1950s date. result prediction likely develop next thirty years 2(a)). Jointly, first quantification thermally deformations displacements resulting considering 2(b)). This work indicates several degrees Celsius millimeters have affected past 70 deriving surface. Vertical order operational foundations earth retaining structures, they fully mobilize shaft capacity piles induce excessive deflections for walls slabs [9]. Therefore, climate change has might silently contributed documented issues buildings infrastructures [10,11], settlements cracking structural members. Currently, underneath quasi-steady state. Accordingly, obtained indicate limited come. However, ongoing should be mitigated future unwanted structures infrastructures. paper reveals silent yet threatening impact (e.g., foundations, earth-retaining facilities). root issue lies caused islands, slowly become time. In study, city district, informed validated field, been infrastructures. lay groundwork investigations referring districts specific foundation types may islands.

Language: Английский

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impact of heated basements on the performance of borehole GHEs

Symposium on Energy Geotechnics 2023, Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 2, 2023

Increasing urban development is leading to a growing demand for subsurface utilisation. As more infrastructure built into the subsurface, heat from tunnels, sewers, and basements, among others, alter thermal state of ground, acting as sources sinks heat, net-increase underground temperatures, phenomenon known Subsurface Urban Heat Island (SUHI) [7-8]. This additional can have impacts on, example, health maintenance structures, increased ventilation costs spaces, quality quantity groundwater flow [1,2]. However, this in also be harvested by ground-source pump (GSHP) systems provide heating buildings [3-6], operating efficiently due higher ground temperatures reducing these through operation, thus mitigating risks SUHI. work demonstrates how heated basements contribute operation GSHP heating. The area Downing College, located central Cambridge, UK, used case study site, investigating much college’s number geothermal boreholes could provide, when building taken account it not. Measured gas consumption data college are estimate demand. geology site obtained importing historical borehole records wider Cambridge British Geological Survey (BGS) Groundhog® Desktop Geoscientific Information System constraining domain using BGS generated superficial deposit bedrock maps, producing 3D lithological profile region*, while hydrological conditions were measured water level time-series data, wells area, curtesy Environment Agency. A total 88 considered, placed symmetrically courtyard, between main buildings. Typical single U-loop configurations with pipes 32 mm outer diameter. Acknowledging that effect greater shallower regions two typical length values considered: 50 m, providing about 40% required load, 100 100%. simulated over years, full numerical model coupling transfer, flow, pipe governing equations, created COMSOL Multiphysics®. temperature assumed maintained at 18 °C throughout simulation. During first 10 GHEs not operating, allow accumulation occur following which, 40 years simulated. results simulations suggest an increase performance occurs present. For all scenarios, fluid keep decreasing time, around keeps decreasing, making difficult extract heat. Over simulation, reaches minimum -3.20 -2.13 m GHEs, 4.52 3.88 both cases value being simulation second without. COP time presented Figure 1-right, showing difference without increasing former rate. corresponds average shown figure, maximum 0.08 0.05 corresponding 1.10 0.65 °C, respectively. These figures correspond reduction (assuming electricity rate £0.34 per kWh) £17,352 £18,197 GHEs. While relatively small considering suggests energy extracted GHE borheoles present, especially shorter boreholes, potential savings

Language: Английский

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