Geoenergy Modeling II (eBook)

Junior-Prof. Dr. Haibing Shao leads the work group Geothermal Systems Analysis ( https://webmail.springer-sbm.com/owa/redir.aspx?SURL=9Om38Sp3h39lFx5a1p_-9BUiz0RjHJ6aiZPHSVFMK5hk1t-eCX3UCGgAdAB0AHAAcwA6AC8ALwB3AHcAdwAuAHUAZgB6AC4AZABlAC8AaQBuAGQAZQB4AC4AcABoAHAAPwBlAG4APQAzADcANAA4ADIA&URL=https%3a%2f%2fwww.ufz.de%2findex.php%3fen%3d37482) in the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research - UFZ. He is also jointly appointed as a Junior Professor at the Technische Universität Bergakademie Freiberg. His research interests are the numerical modelling of coupled processes in shallow and deep geothermal reservoirs. As a senior developer, he has been working with the open-source scientific software OpenGeoSys (www.opengeosys.org) for more than 10 years. He studied environmental engineering at the Tongji University in Shanghai (China) and obtained his Master’s degree at the University of Tübingen. In 2010, he earned his PhD title from TU Dresden, and since then working as a staff scientist at the UFZ.  Philipp Hein is at the time of publication enrolled as a PhD student at Technische Universität Dresden and was working as a research assistant at University of Applied Sciences Leipzig as well as a guest scientist at the Department of Environmental Informatics of the Helmholtz Centre of Environmental Research - UFZ Leipzig. His research interests are the sustainable and efficient utilization of shallow geothermal energy and numerical modeling of borehole heat exchanger coupled ground source heat pump systems. Philipp Hein studied mechanical engineering and received a Bachelor and Master degree at the University of Applied Sciences Düsseldorf. Dr. Agnes Sachse is a postdoctoral researcher at the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research – UFZ in Leipzig, Germany. She studied Geography, Meteorology and Geology and received her doctoral degree in hydrogeology from the Technical University of Dresden in Germany. Her current research interests include the hydrological and hydrogeological modeling on catchment scale, especially the numerical modelling of groundwater recharge and groundwater flow in data scarce regions using OpenGeoSys. She is also responsible for the coordination and implementation of OpenGeoSys-tutorials and lectures. Prof. Dr.-Ing. Olaf Kolditz is the head of the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research - UFZ. He holds a Chair in Applied Environmental System Analysis at the Technische Universität in Dresden. His research interests are related to environmental fluid mechanics, numerical methods and software engineering with applications in geotechnics, hydrology and energy storage. Olaf Kolditz is the PI of the OpenGeoSys project (www.opengeosys.org), an open-source scientific software platform for the numerical simulation of thermo-hydro-mechanical-chemical processes in porous media, in use worldwide. He studied theoretical mechanics and applied mathematics at the University of Kharkov (Ukraine) and earned his PhD in 1990 in natural sciences from the Academy of Science of the GDR in geohydrodynamics. Olaf Kolditz is Editor-in-Chief of two international journals: Geothermal Energy (open access) and Environmental Earth Sciences (ISI).    

Foreword 5
Acknowledgments 7
Contents 8
List of Contributors 11
1 Introduction 12
1.1 Geothermal Systems 12
1.2 Geothermal Resources 13
1.3 Utilizing Shallow Geothermal Resources 14
1.4 Tutorial and Course Structure 16
2 Theory: Governing Equations and Model Implementations 17
2.1 Conceptual Model of the BHEs 17
2.2 Governing Equations 19
2.2.1 Governing Equations for the Heat Transport Process in Soil 19
2.2.2 Governing Equations for the Borehole Heat Exchangers 19
2.2.3 Calculation of the Cauchy Type of Boundary Conditions 20
2.3 Numerical Model 20
2.3.1 Mesh Arrangement 20
2.3.2 Finite Element Discretization 22
2.3.3 Assembly of the Global Equation System 25
2.3.4 Picard Iterations and Time Stepping Schemes 26
3 OGS Project: Simulating Heat Transport Model with BHEs 28
3.1 Download and Compile the Source Code 28
3.1.1 Download the Source Code 28
3.1.2 Using CMake to Configure the Building Project 30
3.1.3 Compiling the Code 31
3.2 Define Heat Transport Process with BHEs 33
3.2.1 Process Definition 33
3.2.2 Deactivated Sub-domains 34
3.2.3 Primary Variables 34
3.3 Geometry of BHEs 34
3.4 Mesh of BHEs 35
3.5 Parameters of BHEs 36
3.6 Initial Conditions for the BHE 40
3.7 Boundary Conditions for the BHE 41
3.8 Output of Temperatures 42
3.9 Running the OGS Model 42
3.10 Visualization of Temperature Evolution 44
3.10.1 Visualization of Soil Temperatures 44
3.10.2 Visualization of BHE Temperatures 45
4 BHE Meshing Tool 48
4.1 Requirement on the Mesh 49
4.2 Input File for the Meshing Tool 49
4.3 Output 51
5 Benchmarks 55
5.1 Borehole Heat Exchangers: Comparison to Line Source Model 55
5.1.1 ILS Analytical Solution 56
5.1.2 Numerical Line Source Model 56
5.1.3 Numerical BHE Model 57
5.1.4 Results 60
5.2 Borehole Heat Exchangers: Comparison to Sandbox Experiment 60
5.2.1 Model Setup 61
5.2.2 OGS Input Files 63
5.2.2.1 Initial and Boundary Conditions 63
5.2.2.2 RFD Data File 65
5.2.2.3 Medium Properties 66
5.2.3 Results 67
6 Case Study: A GSHP System in the Leipzig Area 69
6.1 The Leipzig-Area Model 69
6.1.1 Scenario 69
6.1.2 BHE Design 70
6.1.3 Model Domain 70
6.1.4 Initial and Boundary Conditions 71
6.1.5 Input Files 72
6.1.6 Geometry 72
6.1.7 Process Definition 74
6.1.8 Numerical Properties 74
6.1.9 Time Discretization 75
6.1.10 Initial and Boundary Conditions 75
6.1.11 Data RFD File 78
6.1.12 Fluid Properties 80
6.1.13 Solid Phase Properties 80
6.1.14 Medium Properties 81
6.2 Simulation Results 83
6.3 Implifications of the Model 84
6.3.1 Overall Dynamics of the BHE Coupled GSHP System 85
6.3.2 The Role of the Heat Pump 85
6.3.3 The Price of Under-Design 86
7 Summary and Outlook 88
A Symbols 89
B Keywords 91
B.1 GLI: Geometry 91
B.2 MSH: Finite Element Mesh 91
B.3 PCS: Process Definition 92
B.4 NUM: Numerical Properties 92
B.5 TIM: Time Discretization 93
B.6 IC: Initial Conditions 94
B.7 BC: Boundary Conditions 94
B.8 ST: Source/Sink Terms 95
B.9 MFP: Fluid Properties 95
B.10 MSP: Solid Properties 96
B.11 MMP: Porous Medium Properties 96
B.12 OUT: Output Parameters 97
References 98