Hjem

Foreword xiii Preface xv About the Author xvii Acknowledgements xix Note on the Examples and Costs xxi List of Symbols xxiii 1 Introduction 1
1.1 Photovoltaics - What''s It All About? 1
1.2 Overview of this Book 10
1.3 A Brief Glossary of Key PV Terms 11
1.3.1 Relevant Terminology Relating to Meteorology, Astronomy and Geometry 11
1.3.2 PV Terminology 13
1.4 Recommended Guide Values for Estimating PV System Potential 14
1.4.1 Solar Cell Efficiency ηPV 14
1.4.2 Solar module Efficiency ηm 14
1.4.3 Energy Efficiency (Utilization Ratio, System Efficiency) ηE 15
1.4.4 Annual Energy Yield per Installed Kilowatt of Peak Installed Solar Generator Capacity 15
1.4.5 PV Installation Space Requirements 17
1.4.6 Cost per Installed Kilowatt of Peak Power 17
1.4.7 Feed-in Tariffs; Subsidies 18
1.4.8 Worldwide Solar Cell Production 20
1.4.9 Installed Peak Capacity 21
1.4.10 The Outlook for Solar Cell Production 22
1.5 Examples 24
1.6 Bibliography 25 2 Key Properties of Solar Radiation 27
2.1 Sun and Earth 27
2.1.1 Solar Declination 27
2.1.2 The Apparent Path of the Sun 28
2.2 Extraterrestrial Radiation 31
2.3 Radiation on the Horizontal Plane of the Earth''s Surface 32
2.3.1 Irradiated Energy H on the Horizontal Plane of the Earth''s Surface 34
2.4 Simple Method for Calculating Solar Radiation on Inclined Surfaces 39
2.4.1 Annual Global Irradiation Factors 44
2.4.2 Elementary Radiation Calculation Examples for Inclined Surfaces 47
2.5 Radiation Calculation on Inclined Planes with Three-Component Model 49
2.5.1 Components of Global Radiation on the Horizontal Plane 49
2.5.2 Radiation Reflected off the Ground 50
2.5.3 The Three Components of Radiation on Inclined Surfaces 51
2.5.4 Approximate Allowance for Shading by the Horizon 54
2.5.5 Effect of Horizon and Façade/Roof Edge Elevation on Diffuse Radiation (Sky and Reflected Radiation) 58
2.5.6 Total Energy Incident on Inclined Surfaces (Generic Case) 62
2.5.7 Retrospective Calculation of Irradiance Incident on Inclined Solar Generators, Using Global Radiation Readings on the Horizontal Plane 63
2.5.8 Examples of Radiation Calculations with the Three-Component Method 64
2.6 Approximate Annual Energy Yield for Grid-Connected PV Systems 68
2.6.1 Examples for Approximate Energy Yield Calculations 69
2.7 Composition of Solar Radiation 69
2.8 Solar Radiation Measurement 71
2.8.1 Pyranometers 71
2.8.2 Reference Cells 71
2.8.3 Pyranometer Versus Reference Cell Measurements 73
2.9 Bibliography 76 3 Solar Cells: Their Design Engineering and Operating Principles 79
3.1 The Internal Photoelectric Effect in Semiconductors 79
3.2 A Brief Account of Semiconductor Theory 81
3.2.1 Semiconductor Doping 81
3.2.2 The P-N Junction 83
3.2.3 Characteristic Curves of Semiconductor Diodes 85
3.3 The Solar Cell: A Specialized Semiconductor Diode with a Large Barrier Layer that is Exposed to Light 86
3.3.1 Structure of a Crystalline Silicon Solar Cell 86
3.3.2 Equivalent Circuit of a Solar Cell 87
3.3.3 Characteristic Curves of Solar Cells 89
3.4 Solar Cell Efficiency 94
3.4.1 Spectral Efficiency ηS (of Solar Cells with a Single Junction) 94
3.4.2 Theoretical Efficiency ηT (of Solar Cells with a Single Junction) 97
3.4.3 Practical Efficiency ηPV (at a Junction) 100
3.4.4 Efficiency Optimization Methods 104
3.5 The Most Important Types of Solar Cells and the Attendant Manufacturing Methods 108
3.5.1 Crystalline Silicon Solar Cells 108
3.5.2 Gallium Arsenide Solar Cells 111
3.5.3 Thin-Film Solar Cells 114
3.5.4 Dye Sensitized Solar Cell (DSSC; Photoelectrochemical Solar Cells, Grätzel Solar Cells) 121
3.6 Bifacial Solar Cells 122
3.7 Examples 122
3.8 Bibliography 124 4 Solar Modules and Solar Generators 127
4.1 Solar Modules 127
4.2 Potential Solar Cell Wiring Problems 138
4.2.1 Characteristic Curves of Solar Cells in all Quadrants 138
4.2.2 Wiring Solar Cells in Series 140
4.2.3 Parallel-Connected Solar Cells 147
4.3 Interconnection of Solar Modules and Solar Generators 149
4.3.1 Series Connection of Solar Modules to a String 149
4.3.2 Parallel-Connected Solar Modules 152
4.3.3 Solar Generators with Parallel-Connected Series Strings 152
4.3.4 Solar Generators with Solar Module Matrixing 159
4.4 Solar Generator Power Loss Resulting from Partial Shading and Mismatch Loss 160
4.4.1 Power Loss Induced by Module Shading 160
4.4.2 Mismatch Loss Attributable to Manufacturing Tolerances 163
4.4.3 Mismatch Loss Attributable to String Inhomogeneity 166
4.5 Solar Generator Structure 166
4.5.1 Solar Generator Mounting Options 166
4.5.2 Mounting Systems 176
4.5.3 Electrical Integration of Solar Generators 184
4.5.4 DC Wiring Power Loss 196
4.5.5 Grounding Problems on the DC Side 198
4.5.6 Structure of Larger-Scale Solar Generators 199
4.5.7 Safety Protection Against Touch Voltage 201
4.5.8 Factors that Reduce Solar Generator Power Yield 202
4.6 Examples 217
4.7 Bibliography 221 5 PV Energy Systems 223
5.1 Stand-alone PV Systems 223
5.1.1 PV System Batteries 225
5.1.2 Structure of Stand-alone PV Systems 242
5.1.3 PV Installation Inverters 248
5.1.4 Stand-alone Installation DC Appliances 258
5.1.5 Stand-alone 230 V AC PV Installations 259
5.1.6 Stand-alone PV Installations with Integrated AC Power Busses 259
5.2 Grid-Connected Systems 262
5.2.1 Grid-Connected Operation 262
5.2.2 Design Engineering and Operating Principles of PV System Inverters 266
5.2.3 Standards and Regulations for Grid-Connected Inverters 277
5.2.4 Avoidance of Islanding and Stand-alone Operation in Grid Inverters 288
5.2.5 Operating Performance and Characteristics of PV Grid Inverters 302
5.2.6 Problems that Occur in Grid-Connected Systems and Possible Countermeasures 347
5.2.7 Regulation and Stability Problems in Grid Systems 368
5.3 Bibliography 389 6 Protecting PV Installations Against Lightning 395
6.1 Probability of Direct Lightning Strikes 395
6.1.1 Specimen Calculation for the Annual Number of Direct Lightning Strikes N D 397
6.2 Lightning Strikes: Guide Values; Main Effects 398
6.2.1 Types of Lightning 398
6.2.2 Effects of Lightning 399
6.2.3 Lightning Protection Installation Classes and Efficiency 399
6.2.4 Use of Approximate Solutions for Lightning Protection Sizing 399
6.3 Basic principles of Lightning Protection 400
6.3.1 Internal and External Lightning Protection 400
6.3.2 Protection Zone Determination Using the Lightning Sphere Method 400
6.3.3 Protection Zone for Lightning Conductors and Lightning Rods 401
6.3.4 Lightning Protection Measures for Electricity Installations 402
6.4 Shunting Lightning Current to a Series of Down-conductors 402
6.5 Potential Increases; Equipotential Bonding 404
6.5.1 Equipotential Bonding Realization 405
6.5.2 Lightning Current in Conductors that are Incorporated into the Equipotential Bonding Installation 405
6.5.3 Lightning Protection Devices 407
6.6 Lightning-Current-Induced Voltages and Current 408
6.6.1 Mutual Inductance and Induced Voltages in a Rectangular Loop 409
6.6.2 Proximity Between Down-conductors and other Installations 413
6.6.3 Induced Current 415
6.6.4 Voltages in Lightning-Current-Conducting Cylinders 429
6.7 PV Installation Lightning Protection Experiments 432
6.7.1 Introduction 432
6.7.2 The Surge Current Generator 432
6.7.3 Test Apparatus for Solar Module Characteristic Curves 433
6.7.4 Solar Cell and Solar Module Damage Induced by Surge Current 435
6.7.5 Improving Module Immunity to Lightning Current 439
6.7.6 Mini-lightning Conductors for PV Installations 440
6.7.7 Measurement of Induced Voltage in Individual Modules 440
6.7.8 Voltage Induced in Wired Solar Generators 450
6.7.9 Conclusions Drawn from the Test Results 458
6.8 Optimal Sizing of PV Installation Lightning Protection Devices 459
6.8.1 Solar Module Mutual Inductance 460
6.8.2 Wiring Mutual Inductance 461
6.8.3 Specimen Calculation for MS and Vmax in a Whole String 462
6.8.4 Effects of Distant Lightning Strikes 463
6.9 Recommendations for PV Installation Lightning Protection 470
6.9.1 Possible Protective Measures 470
6.9.2 Protection Against Distant Lightning Strikes 471
6.9.3 Protection Against Both Distant and Nearby Strikes (up to about 20 m) 475
6.9.4 Protection Against Direct Lightning Strikes on PV Installations and Buildings 476
6.9.5 Lightning Protection for Large-Scale Ground-Based PV Installations 479
6.9.6 Lightning Protection for PV Installations on Flat Roofs 480
6.9.7 PV Installation Lightning Protection as Prescribed by Swiss Law 481
6.10 Recap and Conclusions 484
6.11 Bibliography 485 7 Normalized Representation of Energy and Power of PV Systems 487
7.1 Introduction 487
7.2 Normalized Yields, Losses and Performance Ratio 487
7.2.1 Normalized Yields 487
7.2.2 Definition of Normalized Losses 490
7.2.3 P