Shallow Geothermal Systems E-Book

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 363

Veröffentlichungsjahr: 2016

Beschreibung

The recommendations summarise the state of the art. Their aim is the proper exploitation of the ground for geothermal purposes without adversely affecting the ground or the groundwater on the one hand and the operation of the system and nearby buildings on the other. The recommendations should be used during consulting, design, installation and operation in order to achieve optimum and sustainable use of the ground at a specific location. Authorities responsible for supervising and approving projects can use the recommendations as a guide when taking decisions and making stipulations.
The Geothermal Energy Study Group was set up in Bochum in 2004 and became the joint DGGV/DGGT study group in 2007. Some 20 specialists from universities, authorities and engineering consultants are active in the group and meet two or three times a year.

Leseprobe

CONTENTS

Cover

Title Page

Copyright

Preface

Acknowledgements

List of Figures

List of Tables

Preamble

Notation

Chapter 1: Introduction

Chapter 2: Principles

2.1 Geological, Hydrogeological and Geotechnical Principles

2.2 Geothermal Principles

2.3 Solar Energy Zone

2.4 Geosolar Transition Zone

2.5 Terrestrial Zone

2.6 Anthropogenic Thermal Influence

2.7 Interaction Between Geothermal Energy Systems and the Ground

Chapter 3: Geothermal Energy Installations

3.1 Closed Systems

3.2 Open Systems (Direct Use of Groundwater)

3.3 Geothermal Energy Storage Concepts

Chapter 4: Legislative Principles

4.1 Water Legislation

4.2 Mining Legislation

4.3 Natural Mineral Deposits Legislation

4.4 Nature and Landscape Conservation

4.5 Environmental Impact Assessment

4.6 Non-Statutory Regulations

Chapter 5: Planning Principles

5.1 Project Workflow

5.2 Surveying Requirements for BHE Installations

5.3 Models for Simulating Heat Transfer

Chapter 6: Boreholes and Completion

6.1 Drilling Methods

6.2 Equipment in Boreholes

6.3 Boreholes: Deviation from the Vertical

6.4 Geological and Hydrogeological Influences

6.5 Response Test Methods

Chapter 7: Design, Construction and Operation of Closed Systems

7.1 BHE Systems

7.2 Horizontal Collectors

Chapter 8: Design, Construction and Operation of Open Systems

8.1 Well Systems

8.2 Aquifer Thermal Energy Storage (ATES)

Chapter 9: Risk Potential

9.1 The 5-M Method

9.2 Geological Risks

9.3 Hydrogeological Risks

9.4 Environmental Risks

9.5 Risks during BHE Installation

9.6 Operational Risks

Literature

Glossary

End User License Agreement

List of Tables

Table 2.1

Table 2.2

Table 2.3

Table 2.4

Table 2.5

Table 2.6

Table 5.1

Table 6.1

Table 6.2

Table 6.3

Table 6.4

Table 6.5

Table 7.1

Table 7.2

Table 7.3

Table 7.4

Table 7.5

Table 8.1

Table 8.2

Table 8.3

Table 8.4

Table 8.5

Table 9.1

List of Illustrations

Fig. 1.0.1

Fig. 2.2.1

Fig. 2.2.2

Fig. 2.2.3

Fig. 2.2.4

Fig. 2.2.5

Fig. 2.2.6

Fig. 2.2.7

Fig. 2.2.8

Fig. 2.2.9

Fig. 2.2.10

Fig. 2.3.1

Fig. 2.3.2

Fig. 2.3.3

Fig. 2.4.1

Fig. 2.4.2

Fig. 2.6.1

Fig. 3.0.1

Fig. 3.1.1

Fig. 3.1.2

Fig. 3.1.3

Fig. 3.1.4

Fig. 3.1.5

Fig. 3.1.6

Fig. 3.1.7

Fig. 3.1.8

Fig. 3.1.9

Fig. 3.1.10

Fig. 3.1.11

Fig. 3.1.12

Fig. 3.1.13

Fig. 3.1.14

Fig. 3.1.15

Fig. 3.1.16

Fig. 3.1.17

Fig. 3.1.18

Fig. 3.1.19

Fig. 3.2.1

Fig. 3.2.2

Fig. 3.2.3

Fig. 3.2.4

Fig. 3.2.5

Fig. 3.2.6

Fig. 3.2.7

Fig. 3.2.8

Fig. 3.3.1

Fig. 3.3.2

Fig. 6.1.1

Fig. 6.2.1

Fig. 6.3.1

Fig. 6.3.2

Fig. 6.3.3

Fig. 6.3.4

Fig. 6.3.5

Fig. 6.3.6

Fig. 6.3.7

Fig. 6.3.8

Fig. 6.5.1

Fig. 6.5.2

Fig. 6.5.3

Fig. 6.5.4

Fig. 6.5.5

Fig. 6.5.6

Fig. 6.5.7

Fig. 6.5.8

Fig. 6.5.9

Fig. 6.5.10

Fig. 6.5.11

Fig. 6.5.12

Fig. 6.5.13

Fig. 6.5.14

Fig. 6.5.15

Fig. 6.5.16

Fig. 6.5.17

Fig. 6.5.18

Fig. 6.5.19

Fig. 6.5.20

Fig. 6.5.21

Fig. 6.5.22

Fig. 6.5.23

Fig. 7.1.1

Fig. 7.1.2

Fig. 7.1.3

Fig. 7.1.4

Fig. 7.1.5

Fig. 7.1.6

Fig. 7.1.7

Fig. 7.1.8

Fig. 7.1.9

Fig. 7.1.10

Fig. 7.1.11

Fig. 7.1.12

Fig. 7.1.13

Fig. 7.1.14

Fig. 7.1.15

Fig. 7.1.16

Fig. 7.1.17

Fig. 7.1.18

Fig. 7.1.19

Fig. 7.1.20

Fig. 7.1.21

Fig. 7.1.22

Fig. 7.1.23

Fig. 7.1.24

Fig. 7.1.25

Fig. 7.1.26

Fig. 7.1.27

Fig. 7.1.28

Fig. 7.1.29

Fig. 7.1.30

Fig. 7.1.31

Fig. 7.1.32

Fig. 7.1.33

Fig. 7.1.34

Fig. 7.1.35

Fig. 7.1.36

Fig. 7.1.37

Fig. 7.1.38

Fig. 7.1.39

Fig. 7.1.40

Fig. 7.1.41

Fig. 7.1.42

Fig. 7.1.43

Fig. 7.2.1

Fig. 7.2.2

Fig. 8.1.1

Fig. 8.1.2

Fig. 8.1.3

Fig. 8.1.4

Fig. 8.1.5

Fig. 8.1.6

Fig. 8.1.7

Fig. 8.1.8

Fig. 8.1.9

Fig. 8.1.10

Fig. 8.1.11

Fig. 8.1.12

Fig. 8.1.13

Fig. 9.1.1

Fig. 9.1.2

Fig. 9.3.1

Fig. 9.5.1

Fig. 9.5.2

Fig. 9.5.3

Guide

Cover

Table of Contents

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Shallow Geothermal Systems ‒ Recommendations on Design, Construction, Operation and Monitoring

Of the Geothermal Energy Study Group at the specialist Hydrogeology Section of the German Geological Society (FH-DGGV) and the Engineering Geology Section of the German Geotechnical Society and the German Geological Society (FI/DGGT/DGGV).

Edited by

German Geological Society e.V. (DGGV)

and the

German Geotechnical Society e.V. (DGGT)

Deutsche Gesellschaft für Geotechnik e.V.vertr. durch den VorsitzendenHerrn Dr.-Ing. Wolfgang SondermannGutenbergstr. 43 45128 EssenGermany

Deutsche Geologische Gesellschaft – Geologische Vereinigung e.V.vertr. durch den VorsitzendenHerrn Professor Dr. Jan BehrmannBuchholzer Str. 9830655 HannoverGermany

Authors: Sass, I., Brehm, D., Coldewey, W. G., Dietrich, J., Klein, R., Kellner, T., Kirschbaum, B., Lehr, C., Marek, A., Mielke, P., Müller, L., Panteleit, B., Pohl, S., Porada, J., Schiessl, S., Wedewardt, M., Wesche, D.

Translated by Philipp Thrift, Hannover

Cover: Schematic drawings showing the arrangements of the different systems, Graphic: Sass & Mielke 2012

Library of Congress Card No.: applied for

British Library Cataloguing-in-Publication DataA catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche NationalbibliothekThe Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2016 Wilhelm Ernst & Sohn, Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Rotherstraße 21, 10245 Berlin, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Coverdesign: DesignPur, Berlin

Print ISBN: 978-3-433-03140-7

ePDF ISBN: 978-3-433-60670-4

ePub ISBN: 978-3-433-60668-1

eMobi ISBN: 978-3-433-60669-8

oBook ISBN: 978-3-433-60667-4

Preface

The use of shallow geothermal energy has increased enormously over the past ten years. As the number of geothermal energy installations has risen, so has the number of technical developments in the field. There have been cases of damage in connection with the construction and operation of geothermal energy systems which have attracted much attention in the media. In particular, the cases of damage that have become public show that drilling to depths of several hundred metres is a technical activity that calls for responsible procedures in the sense of quality-assured design, construction and operation of the systems. Avoiding damage caused by shallow geothermal energy installations is a top priority for sustainable geothermal energy uses, especially when bodies of groundwater have to be protected against adverse effects. The recommendations in this book should be regarded as contributions to the quality-assured realisation of such systems. One of the aims of the Geothermal Energy Study Group at the specialist Hydrogeology Section of the German Geological Society (DGGV) and the Engineering Geology Section of both the German Geotechnical Society (DGGT) and the DGGV is to promote the widespread use of geothermal energy as an environment-friendly energy source while prioritising the protection of bodies of water. The authors as well as the DGGV and the DGGT have conceived these recommendations as advice and not as a set of technical regulations in the sense of a standard. Therefore, the recommendations of the Geothermal Energy Study Group include a number of textbook-like passages and much information on the legislation that affects approvals and permits. At the time of going to print, the preparation of a standard for shallow geothermal energy was not in sight; such a standard is, however, still regarded as essential.

The authors and their assistants in the study group are hydrogeologists, engineering geologists and engineers from design consultants, the construction industry, the building materials industry, authorities and universities. They drew up the recommendations over a number of years and all were well aware of the fact that some of the content could certainly trigger controversy in technical circles.

In order to guarantee the technical quality of the recommendations of the Geothermal Energy Study Group, the content was subjected to a peer review process. Prof. Dr. Ingrid Stober (Freiburg Regional Authority), Prof. Dr. Rolf Bracke (International Geothermal Center, Bochum) and Prof. Dr. Dmitry V. Rudakov (National Mining University, Dnipropetrovsk) undertook this important and demanding task, approaching it from different perspectives. Their remarks and comments were carefully considered in the preparation of this current edition of the recommendations.

Besides the peer review process, the publishers made the recommendations publicly available on the Internet for three months. Anybody who was interested was invited to submit their remarks, comments and suggestions for improvements within those three months. The authors read and evaluated every single contribution received, which resulted in many improvements being made to the text and illustrations. We are very grateful to all who made contributions to the work of the study group in this way.

The authors of the recommendations are as follows:

Spokesman for the study group

Prof. Dr. rer. nat. Ingo Sass

Institute of Applied Geothermal Science & Technology

Technische Universität Darmstadt

Schnittspahnstr. 9

64287 Darmstadt

Deputy spokesman

Dr. rer. nat. Dirk Brehm

BGU, Bielefeld

Permanent members of the study group

Prof. Dr. rer. nat. Wilhelm Georg Coldewey

Institute of Geology & Palaeontology

Westfälische Wilhelms-Universität Münster

Dr. rer. nat. Jörg Dietrich

HeidelbergCement, Enningerloh

Dr. rer. nat. Rainer Klein

boden & grundwasser, Amtzell

Dipl.-Min. Torsten Kellner

Berlin

Dipl.-Ing. Dipl.-Geol. Bernd Kirschbaum

Federal Environment Agency, Dessau

Dipl.-Geol. Clemens Lehr

Geotechnisches Umweltbüro Lehr, Bad Nauheim

Dipl.-Geol. Adam Marek

Environment Department, Bielefeld

Dipl.-Ing. Philipp Mielke

Institute of Applied Geothermal Science & Technology

Technische Universität Darmstadt

Prof. Dr. rer. nat. Lutz Müller

Environmental Engineering Department

Ostwestfalen-Lippe University of Applied Sciences, Höxter

Dr. rer. nat. Björn Panteleit

Geological Services Agency for Bremen (GDfB)

Dipl.-Geol. Stefan Pohl

geo consult POHL, Bendorf

Dipl.-Geol. Joachim Porada

Porada GeoConsult GmbH & Co. KG, Harsefeld

Dipl.-Ing. Stefan Schiessl

TERRASOND GmbH & Co. KG, Günzburg

Dr. rer. nat. Marec Wedewardt

Senate Department for Urban Development & the Environment, Berlin

Dominik Wesche, MSc Geosciences

Institute of Geology & Palaeontology

Westfälische Wilhelms-Universität Münster

Prof. Dr. Ingo SassMarch 2016Darmstadt

Acknowledgements

On behalf of the associations responsible for publishing the recommendations and the members of the DGGV/DGGT Geothermal Energy Study Group, we would like to thank all those dedicated people who contributed to and supported the preparation of this book. We are grateful to the following temporary members of the study group:

Dipl.-Geol. Gisela Augustin, Hamburg

Dipl.-Ing. Arne Buss, Berlin

Dr. Verena Herrmann, GMP-Geotechnik GmbH, Würzburg

Dr. Claus Heske, International Geothermal Centre, Bochum

Dr. habil. Holger Knoke, IBES GmbH, Neustadt/Weinstraße

Prof. Dr. Martin Sauter, Göttingen University

Dipl.-Geol. Ingo Schäfer, Geological Department of North Rhine-Westphalia, Krefeld

Prof. Dr. Dietmar Schenk (dec.), Mainz University

Dipl.-Geol. Christian Spang, Dr. Spang Ingenieurgesellschaft für Bauwesen, Geologie und Umwelttechnik mbH, Witten

Dipl.-Geol. Andreas Terglane, HPC AG, Stuttgart

The tight schedule of working sessions and voting would not have been possible without the relentless organisation and support of Ms. Simone Ross-Krichbaum at TU Darmstadt. Dipl.-Ing. Sebastian Homuth, MSc, TU Darmstadt, took on the task of proofreading the manuscript, for which we are very thankful. Andreas Hofheinz, assistant at TU Darmstadt, proved to be especially dependable when it came to assembling texts, dealing with layout issues, integrating illustrations and typesetting equations for the study group.

We are also grateful to the boards and managers of the DGGV and DGGT and the members of their specialist sections for actively supporting the work of the Geothermal Energy Study Group.

On behalf of all the members of the study group and the DGGV and DGGT, the associations responsible for publishing the recommendations, we would like to thank Prof. Dr. Ingrid Stober, Freiburg, and Prof. Dr. Rolf Bracke, Bochum, for carrying out the highly demanding and very time-consuming peer review.

List of Tables

Table 2.1 Heat capacity Ca (Ws · K−1) of non-frozen soils.

Table 2.2 Thermal conductivity (W · m−1 · K−1) of non-frozen soils.

Table 2.3 Heat capacity Ca (Ws · K−1) of frozen soils.

Table 2.4 Thermal conductivity λ (W · m−1 · K−1) of frozen soils.

Table 2.5 Typical thermal conductivity values for various rocks.

Table 2.6 The 15 climate zones in Germany.

Table 5.1 Planning tools and numerical simulation models for designing geothermal energy systems.

Table 6.1 Overview of drilling methods.

Table 6.2 Installation aids for continuous pipes for BHEs.

Table 6.3 Simplified geological conditions and the associated design valuesa for the sample calculation.

Table 6.4 Variation in BHE depth with BHEs in an open rectangle.

Table 6.5 Geological risk features and preparatory measures with technical countermeasures to be carried out during the construction phase (drilling, installation of special pipework, backfilling).

Table 7.1 Backfill materials for BHEs: material parameters and requirements.

Table 7.2 Limit values for exposure classes for water aggressive to concrete according to DIN EN 206.

Table 7.3 Examples of pipes and their volumes.

Table 7.4 Permissible amounts of drained water per metre of BHE according to SN EN 805, which may not be exceeded for the pressure drop.

Table 7.5 Comparison of a number of physico-chemical parameters of monoethylene glycol and monopropylene glycol.

Table 8.1 Chronological workflow for iterative well design.

Table 8.2 Hydrochemistry and well capacity limitations.

Table 8.3 Typical inorganic compounds involved in fouling and scaling phenomena in wells.

Table 8.4 Analytics for investigating a body of groundwater.

Table 8.5 Free analytical and numerical calculation software for hydrochemical issues.

Table 9.1 The occupational hazards faced by a drilling contractor and the associated safeguards.

Preamble

The members of the Geothermal Energy Study Group, organised under the auspices of the specialist Hydrogeology (FH-DGGV) and Engineering Geology (FI-DGGV/DGGT) sections of the German Geological Society (DGGV) and the German Geotechnical Society (DGGT), are pleased that you are interested in the recommendations contained in Shallow Geothermal Systems – Recommendations on Design, Construction, Operation and Monitoring. These recommendations represent the results of the ongoing work of the Geothermal Energy Study Group (DGGT Working Group 4.11). The members of the study group are experts drawn from all areas involved with geothermal energy: industry, authorities, consulting, polytechnics and universities.

The publication of this book of recommendations is one of the main tasks of the study group. The recommendations are initially limited to shallow geothermal energy, but the intention is to consider aspects of deep geothermal energy as well. Furthermore, the recommendations are intended to form the technical foundation for basic and further training events aimed at the personnel of drilling contractors and based on standard DIN EN ISO 22475-1: ‘Qualification in drilling boreholes for geothermal purposes and installing closed heat transfer systems (borehole heat exchangers)’ (DGGT/DGGV, 2010).

The study group holds regular working sessions – about four to six times a year. One of the main tasks of the study group is the publication of advice and recommendations for the members of the specialist sections at the DGGV/DGGT and DGGV as well as others who are concerned with geothermal energy issues. The recommendations consider, in particular, the underground parts of the different geothermal energy systems. The most important aspects of the geothermal use of the ground are touched upon, although the focus is clearly on the most frequent types of application – borehole heat exchangers and well systems. Many special methods, techniques or combinations of methods are available on the market. The fact that those are not yet discussed in detail in these recommendations in no way implies that, for example, the various specialities represent ineffective or less suitable systems; it was merely decided to limit the recommendations to the most common systems in order not to exceed the scope of this book.

One specific aim of the recommendations is the quality-assured design, construction, operation and monitoring of shallow geothermal energy installations. The recommendations are intended to help guarantee the protection of bodies of groundwater without obstructing the further spread of heating and cooling systems based on geothermal energy. Avoiding damage to geothermal energy installations and damage caused by the construction and operation of such systems is central to the issues discussed. In the light of current projects, the book also includes a chapter on dealing with potential risks.

The use of shallow geothermal energy represents a significant, environment-friendly and also safe way of reducing the primary energy consumption of our society. Some 50–60% of the total energy consumption of the industrialised nations of Central Europe can be attributed to the operation of buildings. With virtually no restrictions on location, no direct emissions, the ability to cover the base load and economical operation, this is where geothermal energy can play a role.

1Introduction

In Germany about 60% of the total energy consumption can be attributed to heating and cooling and the operation of buildings. There is great potential for using shallow geothermal energy systems to provide a large proportion of that energy demand. For example, around the year 2000, rising energy prices resulted in rapid developments in the use of shallow geothermal energy for heating buildings (increasingly cooling as well). The reason for the growing popularity of this technology is that up to 70–80% of heating requirements can be covered by geothermal energy, which means that only the rest has to be provided by conventional forms of energy. That results in potentially huge financial savings. Apart from that, geothermal systems save energy – in particular, they reduce the consumption of fossil fuels. The heat pumps needed for heating and the recirculating pumps needed for cooling can also be operated with electricity generated from renewable sources. In 2013, the proportion of renewable energy forms in the new-build sector in Germany was already 29% (22% heat pumps, 7% wood pellets + biogas), with a simultaneous decline in the proportion of oil heating systems down to <1% and gas heating systems down to <47% (BDEW, German Association of Energy & Water Industries, 2008). By 2008 some 64% of new heat pump installations were being used in conjunction with ground couplings. Only about 13% of heat pumps operated with geothermal energy sources are connected to well systems that enable the geothermal energy to be exploited directly. Most heat pumps in operation are based on indirect methods of extracting the geothermal energy through borehole heat exchangers (BHEs), ground heat exchangers and so on (BWP, German Heat Pump Association, 2009).

To some extent the state of the art is specified by guideline VDI 4640, the revised draft Part 1 of which has been available since 2010. One of the documents using this as a basis is the revised DVGW regulation W 120-2 (DVGW, 2013), which in future is intended to regulate quality control issues concerned with the provision of boreholes for heat exchangers. However, so far, training programmes for people in the industry to complement the technical documentation have been lacking. Therefore, when it comes to shallow geothermal energy, considerable responsibility is placed on the geoscientists and engineers who advise clients and design systems.

The provision of energy from below the earth's surface is mainly provided indirectly via borehole heat exchangers, which are also known as downhole heat exchangers (DHE); these can be as deep as 400 m. Most borehole heat exchangers are, however, typically between 70 and 200 m deep, although there is a trend towards deeper boreholes. Such boreholes use a closed system of pipes, usually made from high-density polyethylene (HDPE), in which a thermal transfer fluid (normally water-based) circulates. The operating temperatures are then made available through being coupled to a heat pump. Hundreds of thousands of boreholes that still have to be sunk will have to be assessed in terms of the quality of their design and execution in order to achieve optimum technical and economic efficiencies and, of course, to prevent damage on the one hand and latent risks to groundwater resources on the other.

The use of geothermal energy is constantly on the increase. According to the German Environment Ministry (BMUB, www.erneuerbare-energien.de