Oscillatory Thermal Response Test (OTRT) – An Advanced Method for Gaining Thermal Properties of the Subsurface
Georg-August-Universität Göttingen, Göttingen, Germany
Thermal Response Tests (TRTs) are the state-of-the-art method to obtain the thermal conductivity of the subsurface in the nearby ambience of a borehole heat exchanger (BHE). The results of TRTs are used to determine the necessary depth of the borehole and to make long time predictions about the potential of heat extraction. For a TRT, a constant heat load is injected into the subsurface and the ...
Investigating the Impacts of Hydrogeological Parameters on DSI Efficiency through Numerical Simulation
Y. Jin, E. Holzbecher, S. Ebneth
Department of Applied Geology, GZG, Georg-August- University of Göttingen, Göttingen, Germany
Hölscher Wasserbau, Haren, Germany
Düsensauginfiltration (DSI),‘nozzle-suction-infiltration’, is a new method for dewatering that avoids groundwater abstraction from the aquifer. Drawdown is achieved via pumping of groundwater at upper abstraction section, meanwhile, all the pumped water is injected through the same borehole, but in greater depth. We use COMSOL Multiphysics® for the development of a 2D model that ...
E. Evgin, J. A. Infante Sedano, Z. Fu
University of Ottawa, Ottawa, ON, Canada
A pile transfers structural load to the ground at the surface of its shaft and at its toe. In the calculation of these two components of load, both the deformation characteristics and the strength properties of the soil are needed. In unsaturated soils, matric suction changes the stress-strain-strength behavior of the soil. Similarly, the adhesion and the friction angle at the contact area ...
E. Johansson, J. Acuña, B. Palm
Royal Institute of Technology KTH, Stockholm, Sweden
A field of connected boreholes can be used both for cooling, heating and storage purposes. The boreholes transfer heat to or from the ground, which over time changes the temperature in the ground. It is important that the borehole field is properly sized and evaluated before the construction. This study presents results from borehole field evaluations of inclined boreholes used for cooling ...
Benchmark Calculations with COMSOL of the Transport of Radionuclides Through Clay and Bentonite Barriers in a Geological Repository
M.L. Sentís, F. Altorfer, M. Herfort, A. Jakob, G. Kosakowski, and S. Friedel
Swiss Federal Nuclear Safety Inspectorate, Villigen, Switzerland
Paul Scherrer Institute, Villigen, Switzerland
COMSOL Multiphysics GmbH, Zürich, Switzerland
A benchmark study was carried out by the Swiss Nuclear Safety Inspectorate (ENSI) in collaboration with the Laboratory for Waste Management (LES) of the Paul Scherrer Institute (PSI) in order to evaluate the capabilities of the program COMSOL for the calculation of the transport of radionuclides through clay and bentonite barriers in a geological repository for radioactive waste. In this study ...
Y. Jin, E. Holzbecher, and P. Oberdorfer
A novel method for groundwater lowering, which can be applied at construction sites, for aquifer remediation measures or in open mining, is proposed. In contrast to conventional techniques, dewatering is achieved without water conveyance. In this paper the physical concept of the new technology, referred as single borehole pump & inject, is modeled using COMSOL Multiphysics. Two and three ...
E. Holzbecher, P. Oberdorfer, F. Maier, and Y. Jin
Georg-August Universität Göttingen
Geothermal heat production from deep reservoirs (5000-7000 m) is currently examined, not only in Germany. Our reference set-up consists of two pipes within a single borehole: one for pumping. We examine a design, where a single borehole splits into two legs at a certain depth. The two legs are connected by highly permeable geological, natural or artificial strata in the deep subsurface. The ...
J. Acuna, M. Fossa, P. Monzó
KTH Energy Technology, Stockholm, Sweden
Dime, University of Genova, Genova, Italy
Ground-coupled heat pumps (GCHP) are successfully installed since at about 20 years in many countries to fulfill space conditioning requirements in building applications. In most cases the heat pump is connected to a system of vertical ground heat exchangers (as illustrated in Figure 1) where a fluid is circulated inside a system of pipes inserted in a deep borehole drilled in the soil. Drilling ...
Coupling Heat Transfer in Heat Pipe Arrays with Subsurface Porous Media Flow for Long Time Predictions of Solar Rechargeable Geothermal Systems
P. Oberdorfer, R. Hu, M. Azizur Rahman, E. Holzbecher, M. Sauter, P. Pärisch
Applied Geology, Geoscience Centre, University of Göttingen, Göttingen, Germany
Institute for Solar Energy Research Hameln/Emmerthal (ISFH), Emmerthal, Germany
An increased share of renewable energies is regarded as an integral part of a strategy towards a sustainable future. With regard to the heat supply sector this may be achieved using solar thermal collectors or heat pump systems with borehole heat exchangers. During the last years solar thermal and geothermal systems have generally been installed separately. Now, several proposals are discussed in ...
The Simulation of Pore Scale Fluid Flow with Real World Geometries Obtained from X-Ray Computed Tomography
W. Fourie1, R. Said2, P. Young3, and D. L. Barnes1
1Department of Civil and Environmental Engineering, Water
and Environmental Research Center, University of Alaska, Fairbanks, AK, USA
2Simpleware, Ltd. Exeter, UK
3Computer Science and Mathematics, School of Engineering, University of Exeter, Exeter, UK
With the recent improvement of X-ray Computed Tomography and robust modeling tools, it is now possible to show that pore scale fluid flow modeled by the Navier-Stokes equation can be used to derive macro parameters of Darcy’s Law, such as the hydraulic conductivity. The model allows calculation of isotropy, tortuosity and dispersivity of the soil in all directions. These parameters, which are ...