Influence of hydrogeological parameters on temperature variations due to borehole heat exchangers

Pannike, Simone; Kölling, Martin; Panteleit, Björn; Reichling, J.; Scheps, Volker; Schulz, Horst D

doi:10.1007/s00767-006-0114-2

Cited by 36 publications

(8 citation statements)

References 4 publications

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“…Impacts of shallow geothermal installations on the environment may also arise from changes in groundwater temperature, for example by affecting aquatic habitats (Ferguson 2009). In the case of large facilities (BHE fields), calculations concerning the thermal effects on the groundwater are therefore required in addition (e.g., H€ ahnlein et al 2010;Pannike et al 2006).…”

Section: Water Protection Zone (A U )mentioning

confidence: 99%

Urban Geology

Huggenberger¹,

Epting²

2011

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Section: Water Protection Zone (A U )mentioning

confidence: 99%

Urban Geology

Huggenberger¹,

Epting²

2011

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“…Mesh density increases from left to right BHE components, the elements are very small (\1 mm) inside and directly at the BHE, leading to large mesh sizes of up to 70,000 elements. The thermal and hydraulic parameters for the original model are given in Table 2, with typical values taken from VDI (2010) and Pannike et al (2006). The initial subsurface temperature is T 0 = 9°C at the upper boundary (z = 0 m) and increases with depth following a natural geothermal gradient of dT/ dz = 0.03 K m -1 .…”

Section: Adapted Modelmentioning

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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“…A high and a low soil permeability are assigned to represent heat transport in the soil with and without convection, respectively (Tables 1 and 2). The values in Table 1 were taken from the literature (Pannike et al, 2006;VDI, 2010;HeidelbergCement, 2013aHeidelbergCement, , 2013b. Observation points are placed at increasing distances along the y-axis from the BHE at 500 m depth (Fig.…”

Section: Model Setupmentioning

confidence: 99%

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

Boockmeyer

Bauer

2014

Géotechnique Letters

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Subsurface energy storage of high-temperature heat in middle-deep formations below drinking water aquifers may offer a new possibility of hosting large amounts of energy in the subsurface. An adequate system and process understanding is required in order to predict and assess the complex and interacting induced effects. To this end, the near-field effects of high-temperature heat storage were studied through numerical simulations using a 100 m borehole heat exchanger placed at 500 m depth, accounting for the detailed geometry of U-pipes, grout, borehole and soil. Coupled thermohydraulic simulations showed that the simulated system may store up to 260 MWh of thermal energy using an injection temperature of 90uC and that the temperature evolution with time is strongly dependent on the radial distance from the borehole and the soil permeability and is strongly sensitive to the thermal conductivity of the grout material. At low soil permeability, heat transfer is controlled by conduction and the amount of heat stored is mainly influenced by the soil thermal conductivity. A higher soil permeability leads to convection in the soil with a doubling of the stored heat. In this case, the amount of heat stored is not sensitive to the soil thermal conductivity but to the grout thermal conductivity.

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Influence of hydrogeological parameters on temperature variations due to borehole heat exchangers

Cited by 36 publications

References 4 publications

Urban Geology

Urban Geology

Efficient simulation of multiple borehole heat exchanger storage sites

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

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