Geothermal Heat Pump and Heat Engine Systems Theory And Practice

A unique approach to the study of geothermal energy systems

This book takes a unique, holistic approach to the interdisciplinary study of geothermal energy systems, combining low, medium, and high temperature applications into a logical order. The emphasis is on the concept that all geothermal projects contain common elements of a "thermal energy reservoir" that must be properly designed and managed.

The book is organized into four sections that examine geothermal systems: energy utilization from resource and site characterization; energy harnessing; energy conversion (heat pumps, direct uses, and heat engines); and energy distribution and uses.

Examples are provided to highlight fundamental concepts, in addition to more complex system design and simulation.

Key features:

• Companion website containing software tools for application of fundamental principles and solutions to real-world problems.
• Balance of theory, fundamental principles, and practical application.
• Interdisciplinary treatment of the subject matter.

Geothermal Heat Pump & Heat Engine Systems: Theory and Practice is a unique textbook for Energy Engineering and Mechanical Engineering students as well as practicing engineers who are involved with low-enthalpy geothermal energy systems.

Andrew Chiasson is a faculty member in the Department of Mechanical & Aerospace Engineering, University of Dayton, where he teaches courses and conducts research in the areas of thermofluid sciences, and renewable and clean energy. He has academic and professional practice experience in a wide range of geothermal and hydrogeologic applications related to geothermal heat pumps (geoexchange), direct-use geothermal, small-scale electrical power generation, hydrogeological site evaluations, and groundwater flow and mass/heat transport modeling. Dr. Chiasson has been extensively involved in research and development of design and simulation tools for optimal earth heat exchanger coupling, hybrid geoexchange systems, and underground solar energy storage. As a Professional Engineer in the United States and in Canada, he has designed numerous closed and open-loop geoexchange systems and HVAC systems for a wide variety of building types. He is a member of ASHRAE Technical Committees and is an IGSHPA Accredited Ground Source Heat Pump Trainer.

Series Preface xiv

Preface xv

About the Companion Website xviii

1 Geothermal Energy Project Considerations 1

1.1 Overview 1

1.2 Renewable/Clean Energy System Analysis 1

1.3 Elements of Renewable/Clean Energy Systems 4

1.4 Geothermal Energy Utilization and Resource Temperature 5

1.5 Geothermal Energy Project History and Development 5

1.6 Chapter Summary 18

Discussion Questions and Exercise Problems 19

Part I Geothermal Energy – Utilization and Resource Characterization 21

2 Geothermal Process Loads 23

2.1 Overview 23

2.2 Weather Data 24

2.3 Space Heating and Cooling Loads 26

2.4 Hot Water Process Loads 38

2.5 Swimming Pool and Small Pond Heating Loads 40

2.6 Snow-Melting Loads 46

2.7 Chapter Summary 53

Discussion Questions and Exercise Problems 54

3 Characterizing the Resource 55

3.1 Overview 55

3.2 Origin and Structure of the Earth 56

3.3 Geology and Drilling Basics for Energy Engineers 59

3.4 Earth Temperature Regime and Global Heat Flows: Why is the Center of the Earth Hot? 62

3.5 Shallow Earth Temperatures 64

3.6 The Geothermal Reservoir Concept 66

3.7 Geothermal Site Suitability Analysis 68

3.8 Chapter Summary 79

Discussion Questions and Exercise Problems 80

Part II Harnessing the Resource 81

4 Groundwater Heat Exchange Systems 83

4.1 Overview 83

4.2 Why Groundwater? 84

4.3 Theoretical Considerations 85

4.4 Practical Considerations 108

4.5 Groundwater Heat Pump Systems 123

4.6 Chapter Summary 134

Discussion Questions and Exercise Problems 135

5 Borehole Heat Exchangers 138

5.1 Overview of Borehole Heat Exchangers (BHEs) 138

5.2 What is a Borehole Heat Exchanger? 139

5.3 Brief Historical Overview of BHEs 140

5.4 Installation of BHEs 141

5.5 Thermal and Mathematical Considerations for BHEs 142

5.6 Thermal Response Testing 169

5.7 Pressure Considerations for Deep Vertical Boreholes 175

5.8 Special Cases 176

5.9 Chapter Summary 178

Discussion Questions and Exercise Problems 179

6 Multi-Borehole Heat Exchanger Arrays 181

6.1 Overview 181

6.2 Vertical GHX Design Length Equation and Design Parameters 184

6.3 Vertical GHX Simulation 198

6.4 Hybrid Geothermal Heat Pump Systems 199

6.5 Modeling Vertical GHXs with Software Tools 200

6.6 Chapter Summary 216

Discussion Questions and Exercise Problems 217

7 Horizontal Ground Heat Exchangers 219

7.1 Overview 219

7.2 Horizontal GHX Design Length Equation and Design Parameters 221

7.3 Modeling Horizontal GHXs with Software Tools 232

7.4 Simulation of Horizontal GHXs 237

7.5 Earth Tubes 238

7.6 Chapter Summary 244

Discussion Questions and Exercise Problems 244

8 Surface Water Heat Exchange Systems 246

8.1 Overview 246

8.2 Thermal Processes in Surface Water Bodies 247

8.3 Open-Loop Systems 250

8.4 Closed-Loop Systems 251

8.5 Chapter Summary 266

Discussion Questions and Exercise Problems 266

9 Opportunistic Heat Sources and Sinks 267

9.1 Overview 267

9.2 Use of Existing Water Wells 267

9.3 Heat Exchange With Building Foundations 268

9.4 Utilization of Infrastructure from Other Energy Sectors 268

9.5 Cascaded Loads and Combined Heat and Power (CHP) 271

9.6 Integrated Loads and Load Sharing with Heat Pumps 273

9.7 Chapter Summary 278

Discussion Questions and Exercise Problems 279

10 Piping and Pumping Systems 280

10.1 Overview 280

10.2 The Fluid Mechanics of Internal Flows 281

10.3 Pipe System Design 286

10.4 Configuring a Closed-Loop Ground Heat Exchanger 289

10.5 Circulating Pumps 298

10.6 Chapter Summary 305

Exercise Problems 305

Part III Geothermal Energy Conversion 307

11 Heat Pumps and Heat Engines: A Thermodynamic Overview 309

11.1 Overview 309

11.2 Fundamental Theory of Operation of Heat Pumps and Heat Engines 309

11.3 The Carnot Cycle 311

11.4 Real-World Considerations: Entropy and Exergy 312

11.5 Practical Heat Engine and Heat Pump Cycles 317

11.6 The Working Fluids: Refrigerants 320

11.7 Chapter Summary 322

Discussion Questions and Exercise Problems 323

12 Mechanical Vapor Compression Heat Pumps 324

12.1 Overview 324

12.2 The Ideal Vapor Compression Cycle 325

12.3 The Non-Ideal Vapor Compression Cycle 328

12.4 General Source-Sink Configurations 342

12.5 Mechanics of Operation 347

12.6 Transcritical Cycles 366

12.7 Vapor Compression Heat Pump Performance Standards and Manufacturer’s Catalog Data 370

12.8 Chapter Summary 373

Discussion Questions and Exercise Problems 374

13 Thermally Driven Heat Pumps 376

13.1 Overview 376

13.2 Cycle Basics 377

13.3 Absorption Cycles 378

13.4 Adsorption Cycles 396

13.5 Thermally Driven Heat Pump Performance Standards and Manufacturer’s Catalog Data 397

13.6 Chapter Summary 397

Discussion Questions and Exercise Problems 398

14 Organic Rankine Cycle (Binary) Geothermal Power Plants 399

14.1 Overview 399

14.2 The Ideal Rankine Cycle 400

14.3 The Non-Ideal Rankine Cycle 402

14.4 Organic Rankine Cycle Performance Modeling 410

14.5 Chapter Summary 416

Discussion Questions and Exercise Problems 416

Part IV Energy Distribution 419

15 Inside the Building 421

15.1 Overview 421

15.2 Heat Pump Piping Configurations 421

15.3 Hydronic Heating and Cooling Systems 425

15.4 Forced-Air Heating and Cooling Systems 425

15.5 Ventilation Air and Heat Pumps 426

15.6 Chapter Summary 431

Discussion Questions and Exercise Problems 431

16 Energy Economics and Environmental Impact 433

16.1 Overview 433

16.2 Simple Payback Period and Rate of Return 434

16.3 Time Value of Money 435

16.4 Cost Considerations for Geothermal Energy Systems 437

16.5 Uncertainty in Economic Analyses 439

16.6 Environmental Impact 441

16.7 Chapter Summary 444

Appendix A: Software Used in this Book 445

A.1 The GHX Tool Box 445

A.2 Engineering Equation Solver (EES) 445

A.3 Installing and Using the Excel Solver for Optimization Problems 446

What is the Excel Solver? 446

Installing the Excel Solver 446

Using the Excel Solver 446

Appendix B: Hydraulic and Thermal Property Data 448

Appendix C: Solar Utilizability Method 450

Nomenclature 454

References 459

Index 464

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.