Fundamentals of Renewable Energy Processes (eBook)

Front Cover 1
Fundamentals of Renewable Energy Processes 4
Copyright Page 5
Contents 6
Foreword to the Second Edition 16
Foreword to the First Edition 18
Acknowledgements 20
Chapter 1. Generalities 22
1.1 Units and Constants 22
1.2 Energy and Utility 23
1.3 Conservation of Energy 25
1.4 Planetary Energy Balance 26
1.5 The Energy Utilization Rate 26
1.6 The Population Explosion 30
1.7 The Market Penetration Function 31
1.8 Planetary Energy Resources 37
1.9 Energy Utilization 41
1.10 The Ecology Question 45
1.10.1 Biological 47
1.10.2 Mineral 47
1.10.3 Subterranean 47
1.10.4 Undersea 48
1.11 Nuclear Energy 48
1.11.1 Fission 50
1.11.2 Fusion 55
1.11.3 Cold Fusion 58
1.12 Financing 65
References 67
Problems 69
Part I: Heat Engines 80
Chapter 2. A Minimum of Thermodynamics and of the Kinetic Theory of Gases 82
2.1 The Motion of Molecules 82
2.2 Temperature 82
2.3 The Perfect-Gas Law 83
2.4 Internal Energy 84
2.5 Specific Heat at Constant Volume 84
2.6 The First Law of Thermodynamics 85
2.7 The Pressure-Volume Work 86
2.8 Specific Heat at Constant Pressure 86
2.9 Adiabatic Processes 87
2.9.1 Abrupt Compression 88
2.9.2 Gradual Compression 91
2.9.3 p-V Diagrams 92
2.9.4 Polytropic Law 93
2.9.5 Work Done under Adiabatic Expansion 94
2.10 Isothermal Processes 95
2.11 Functions of State 97
2.12 Enthalpy 97
2.13 Degrees of Freedom 99
2.14 Entropy 100
2.14.1 Changes in Entropy 101
2.15 Reversibility 103
2.15.1 Causes of Irreversibility 105
2.16 Negentropy 105
2.17 How to Plot Statistics 107
2.18 Maxwellian Distribution 108
2.19 Fermi–Dirac Distribution 111
2.20 Boltzmann’s Law 113
Appendix: Symbology 114
Reference 114
Problems 115
Chapter 3. Mechanical Heat Engines 120
3.1 Heats of Combustion 120
3.2 Carnot Efficiency 123
3.3 Engine Types 124
3.4 Efficiency of an Otto Engine 127
3.5 Gasoline 132
3.5.1 Heat of Combustion 132
3.5.2 Antiknock Characteristics 132
3.6 Knocking 132
3.7 Hybrid Engines for Automobiles 136
3.8 The Stirling Engine 137
3.8.1 The Kinematic Stirling Engine 138
3.8.2 The Free-piston Stirling Engine 144
3.9 Cryogenic Engines 146
3.9.1 Conclusions 149
References 149
Problems 151
Chapter 4. Ocean Thermal Energy Converters 160
4.1 Introduction 160
4.2 OTEC Configurations 160
4.3 Turbines 163
4.4 OTEC Efficiency 166
4.5 Example of OTEC Design 167
4.6 Heat Exchangers 169
4.7 Siting 169
References 170
Problems 171
Chapter 5. Thermoelectricity 174
5.1 Experimental Observations 174
5.2 Thermoelectric Thermometers 179
5.3 The Thermoelectric Generator 181
5.4 Figure of Merit of a Material 185
5.5 The Wiedemann–Franz–Lorenz Law 187
5.6 Thermal Conductivity in Solids 190
5.7 Seebeck Coefficient of Semiconductors 192
5.8 Performance of Thermoelectric Materials 192
5.9 Some Applications of Thermoelectric Generators 196
5.10 Design of a Thermoelectric Generator 198
5.11 Thermoelectric Refrigerators and Heat Pumps 201
5.11.1 Design Using an Existing Thermocouple 202
5.11.2 Design Based on Given Semiconductors 205
5.12 Temperature Dependence 209
5.13 Battery Architecture 209
5.14 The Physics of Thermoelectricity 211
5.14.1 The Seebeck Effect 211
5.14.2 The Peltier Effect 214
5.14.3 The Thomson Effect 215
5.14.4 Kelvin’s Relations 216
5.15 Directions and Signs 220
Appendix 222
References 223
Problems 224
Chapter 6. Thermionics 240
6.1 Introduction 240
6.2 Thermionic Emission 243
6.3 Electron Transport 245
6.3.1 The Child–Langmuir Law 248
6.4 Lossless Diodes with Space Charge Neutralization 252
6.4.1 Interelectrode Potentials 252
6.4.2 V -J Characteristics 254
6.4.3 The Open-Circuit Voltage 254
6.4.4 Maximum Power Output 255
6.5 Losses in Vacuum Diodes with No Space Charge 256
6.5.1 Efficiency 256
6.5.2 Radiation Losses 257
6.5.3 Excess Electron Energy 260
6.5.4 Heat Conduction 262
6.5.5 Lead Resistance 262
6.6 Real Vacuum-Diodes 262
6.7 Vapor Diodes 263
6.7.1 Cesium Adsorption 264
6.7.2 Contact Ionization 267
6.7.3 Thermionic Ion Emission 268
6.7.4 Space Charge Neutralization Conditions 269
6.7.5 More V -J Characteristics 270
6.8 High-Pressure Diodes 276
References 278
Problems 279
Chapter 7. AMTEC 284
7.1 Operating Principle 284
7.2 Vapour Pressure 286
7.3 Pressure Drop in the Sodium Vapor Column 288
7.4 Mean Free Path of Sodium Ions 290
7.5 V -I Characteristics of an AMTEC 290
7.6 Efficiency 293
7.7 Thermodynamics of an AMTEC 295
References 298
Chapter 8. Radio-Noise Generators 300
References 304
Part II: The World of Hydrogen 306
Chapter 9. Fuel Cells 308
9.1 Introduction 308
9.2 Voltaic Cells 309
9.3 Fuel Cell Classification 314
9.3.1 Temperature of Operation 315
9.3.2 State of the Electrolyte 316
9.3.3 Type of Fuel 316
9.3.4 Chemical Nature of the Electrolyte 317
9.4 Fuel Cell Reactions 318
9.4.1 Alkaline Electrolytes 318
9.4.2 Acid Electrolytes 318
9.4.3 Molten Carbonate Electrolytes 319
9.4.4 Ceramic Electrolytes 319
9.4.5 Methanol Fuel Cells 319
9.4.6 Formic Acid Fuel Cells 321
9.5 Typical Fuel Cell Configurations 321
9.5.1 Demonstration Fuel Cell (KOH) 321
9.5.2 Phosphoric Acid Fuel Cells (PAFCs) 322
9.5.3 Molten Carbonate Fuel Cells (MCFCs) 324
9.5.4 Ceramic Fuel Cells (SOFCs) 326
9.5.5 Solid-Polymer Electrolyte Fuel Cells 335
9.5.6 Direct Methanol Fuel Cells (DMFCs) 343
9.5.7 Direct Formic Acid Fuel Cells (DFAFCs) 344
9.5.8 Solid Acid Fuel Cells (SAFCs) 345
9.5.9 Metallic Fuel Cells—Zinc–Air Fuel Cells 346
9.6 Fuel Cell Applications 347
9.6.1 Stationary Power Plants 347
9.6.2 Automotive Power Plants 348
9.6.3 Other Applications 349
9.7 The Thermodynamics of Fuel Cells 350
9.7.1 Heat of Combustion 351
9.7.2 Free Energy 352
9.7.3 Efficiency of Reversible Fuel Cells 356
9.7.4 Effects of Pressure and Temperature on the Enthalpy and Free Energy Changes of a Reaction 357
9.8 Performance of Real Fuel Cells 368
9.8.1 Current Delivered by a Fuel Cell 368
9.8.2 Efficiency of Practical Fuel Cells 368
9.8.3 V -I Characteristics of Fuel Cells 370
9.8.4 Open-circuit Voltage 379
9.8.5 Reaction Kinetics 379
9.8.6 The Butler–Volmer Equation 384
9.8.7 Transport Losses 389
9.8.8 Heat Dissipation by Fuel Cells 391
Appendix: Batteries 394
References 414
Further Reading 416
Problems 417
Chapter 10. Hydrogen Production 438
10.1 Generalities 438
10.2 Chemical Production of Hydrogen 440
10.2.1 Historical 440
10.2.2 Metal–Water Hydrogen Production 441
10.2.3 Large-scale Hydrogen Production 443
10.2.4 Hydrogen Purification 447
10.2.5 Compact Fuel Processors 450
10.3 Electrolytic Hydrogen 455
10.3.1 Introduction 455
10.3.2 Electrolyzer Configurations 456
10.3.3 Efficiency of Electrolyzers 458
10.3.4 Concentration-Differential Electrolyzers 461
10.3.5 Electrolytic Hydrogen Compression 463
10.4 Thermolytic Hydrogen 464
10.4.1 Direct Dissociation of Water 464
10.4.2 Chemical Dissociation of Water 470
10.5 Photolytic Hydrogen 472
10.5.1 Generalities 472
10.5.2 Solar Photolysis 474
10.6 Photobiologic Hydrogen Production 477
References 478
Problems 479
Chapter 11. Hydrogen Storage 488
11.1 Compressed Gas 490
11.2 Cryogenic Hydrogen 492
11.3 Storage of Hydrogen by Adsorption 494
11.4 Storage of Hydrogen in Chemical Compounds 495
11.4.1 Generalities 495
11.4.2 Hydrogen Carriers 496
11.4.3 Water Plus a Reducing Substance 497
11.4.4 Formic Acid 498
11.4.5 Metal Hydrides 498
11.5 Hydride Hydrogen Compressors 513
11.6 Hydride Heat Pumps 518
References 520
Problem 522
Part III: Energy from the Sun 540
Chapter 12. Solar Radiation 542
12.1 The Nature of the Solar Radiation 542
12.2 Insolation 545
12.2.1 Generalities 545
12.2.2 Insolation on a Sun-Tracking Surface 548
12.2.3 Insolation on a Stationary Surface 548
12.2.4 Horizontal Surfaces 551
12.3 Solar Collectors 552
12.3.1 Solar Architecture 552
12.3.2 Flat Collectors 555
12.3.3 Evacuated Tubes 556
12.3.4 Concentrators 556
12.4 Some Solar Plant Configurations 559
12.4.1 High-Temperature Solar Heat Engine 559
12.4.2 Solar Tower 561
12.4.3 Solar Ponds 562
Appendix A: The Measurement of Time 563
Appendix B: Orbital Mechanics 567
12.4.4 Orbital Obliquity 579
References 580
Further Reading 580
Problems 581
Chapter 13. Biomass 590
13.1 Introduction 590
13.2 The Composition of Biomass 590
13.2.1 A Little Bit of Organic Chemistry 591
13.3 Biomass as Fuel 613
13.3.1 Wood Gasifiers 615
13.3.2 Ethanol 615
13.3.3 Dissociated Alcohols 621
13.3.4 Anaerobic Digestion 622
13.4 Photosynthesis 629
References 637
Problems 639
Chapter 14. Photovoltaic Converters 646
14.1 Introduction 646
14.2 Theoretical Efficiency 652
14.3 Carrier Multiplication 660
14.4 Spectrally Selective Beam Splitting 661
14.4.1 Cascaded Cells 661
14.4.2 Filtered Cells 665
14.4.3 Holographic Concentrators 665
14.5 Thermophotovoltaic Cells 666
14.6 The Ideal and the Practical 671
14.7 Solid-State Junction Photodiode 672
14.7.1 The Reverse Saturation Current 692
14.7.2 Practical Efficiency 695
14.8 Dye-Sensitized Solar Cells (DSSCs) 696
14.9 Organic Photovoltaic Cells (OPC) 702
14.10 Solar-Power Satellite 711
14.10.1 Beam from Space 713
14.10.2 Solar Energy to DC Conversion 714
14.10.3 Microwave Generation 715
14.10.4 Radiation System 716
14.10.5 Receiving Array 717
14.10.6 Attitude and Orbital Control 717
14.10.7 Space Transportation and Space Construction 718
14.10.8 Future of Space Solar Power Projects 718
Appendix A: Values of Two DefiniteIntegrals Used in the Calculation ofPhotodiode Performance. 719
Appendix B: A Semiconductor Primer 720
References 726
Problem 729
Part IV: Wind and Water 742
Chapter 15. Wind Energy 744
15.1 History 744
15.2 Wind Machine Configurations 748
15.2.1 Drag-Type Wind Turbines 748
15.2.2 Lift-Type Wind Turbines 750
15.2.3 Magnus Effect Wind Machines 751
15.2.4 Vortex Wind Machines 752
15.3 Measuring the Wind 752
15.4 Availability of Wind Energy 756
15.5 Wind Turbine Characteristics 757
15.6 Principles of Aerodynamics 759
15.6.1 Flux 759
15.6.2 Power in the Wind 760
15.6.3 Dynamic Pressure 760
15.6.4 Wind Pressure 761
15.6.5 Available Power (Betz Limit) 762
15.6.6 Efficiency of a Wind Turbine 766
15.7 Airfoils 769
15.8 Reynolds Number 772
15.9 Aspect Ratio 775
15.10 Wind Turbine Analysis 777
15.10.1 Horizontal Axis Turbines (propeller type) 777
15.10.2 Vertical Axis Turbines 783
15.11 Magnus Effect 797
References 798
Problems 799
Chapter 16. Ocean Engines 820
16.1 Introduction 820
16.2 Wave Energy 820
16.2.1 About Ocean Waves 820
16.2.2 Wave Energy Converters 823
16.3 Tidal Energy 829
16.4 Energy from Currents 831
16.4.1 Marine Current Turbine System 832
16.5 Salination Energy 837
16.6 Osmosis 841
References 844
Further Reading 844
Problems 846
Index 850