Series Preface ............................................... xiii
The Series Editor ............................................ xvii
Preface ....................................................... xix
Acknowledgments ............................................. xxiii
The Authors ................................................... xxv
The Contributors ............................................ xxvii
Chapter 1. Introduction to Solar Energy ........................ 1
1.1. The Twenty-First Century's Perfect Energy Storm ........... 1
1.2. Renewable Energy for Rural Development .................... 2
1.3. Renewable Energy Solutions ................................ 3
1.4. Global Solar Resource ..................................... 4
Problems ........................................................ 5
Chapter 2. Solar Resource ...................................... 7
2.1. Introduction .............................................. 7
2.2. Sun-Earth Geometric Relationship .......................... 7
2.2.1. Earth-Sun Distance ............................... 8
2.2.2. Apparent Path of the Sun ......................... 9
2.2.3. Earth and Celestial Coordinate Systems .......... 10
2.2.4. Position of the Sun with Respect to a
Horizontal Surface .............................. 12
2.2.5. Position of the Sun with Respect to a Tilted
Surface ......................................... 22
2.3. Equation of Time ......................................... 26
2.4. Structure of the Sun ..................................... 29
2.5. Electromagnetic Radiation ................................ 30
2.6. Solar Spectral Distribution .............................. 33
2.7. Solar Constant ........................................... 34
2.8. Extraterrestrial Solar Radiation ......................... 36
2.9. Terrestrial Solar Radiation .............................. 37
2.10 Measurement of Terrestrial Solar Radiation ............... 40
2.11. Terrestrial Insolation on Tilted Collectors .............. 42
2.11.1. Instantaneous and Hourly Radiation ............... 46
2.11.2. Monthly Average Daily Insolation ................. 49
References ..................................................... 52
Problems ....................................................... 53
Chapter 3. Fundamentals of Engineering: Thermodynamics
and Heat Transfer .................................. 55
3.1. Introduction ............................................. 55
3.2. Conduction Heat Transfer ................................. 55
3.3. One-Dimensional Conduction Heat Transfer in a
Rectangular Coordinate ................................... 57
3.4. Thermal Resistance Circuits .............................. 59
3.5. One-Dimensional Conduction Heat Transfer in
a Cylindrical Coordinate ................................. 60
3.6. Convection Heat Transfer ................................. 63
3.7. Radiation Heat Transfer .................................. 65
3.7.1. Surface Property ................................. 66
3.7.2. Blackbody Radiation .............................. 66
3.7.3. Real Body Radiation .............................. 67
3.8. Introduction to Thermodynamics ........................... 68
3.8.1. The First Law of Thermodynamics .................. 68
3.8.2. The Second Law of Thermodynamics ................. 69
3.8.3. The Third Law of Thermodynamics .................. 70
References ..................................................... 70
Problems ....................................................... 71
Chapter 4. Solar Thermal Systems and Applications ............. 73
4.1. Introduction ............................................. 73
4.2. Solar Collectors ......................................... 73
4.2.1. Flat-Plate Collectors ............................ 74
4.2.1.1. Flat-Plate Collector Thermal
Testing ................................ 76
4.2.1.2. Collector Efficiency Curve ............. 78
4.2.2. Evacuated-Tube Solar Collectors .................. 78
4.2.3. Concentrating Collectors ......................... 80
4.2.3.1. Optic Fundamentals for Solar
Concentration .......................... 84
4.2.3.2. Parabolic Concentrators ................ 87
4.2.4. Compound Parabolic Concentrators (CPCs) .......... 90
4.2.5. Fresnel Lens Concentrators ....................... 94
4.2.6. Heliostats ....................................... 94
4.3. Tracking Systems ......................................... 96
4.4. Solar Thermal Systems .................................... 97
4.4.1. Passive and Active Solar Thermal Systems ......... 99
4.4.1.1. Solar Thermal Application: Water
Heating for Domestic Use ............... 99
4.4.1.2. Solar Thermal Application: Water
Heating for Industrial Use ............ 103
4.4.2. Case of Active Solar Drying: Sludge Drying ...... 103
4.4.2.1. Solar Thermal Application: Solar
Distillation ......................... 106
4.4.3. Case of Passive Direct and Indirect Solar
Distillation: Water Desalination ................ 108
4.4.4. Case of Passive Solar Indirect Drying:
Food Drying ..................................... 110
4.4.5. Case of an Active Solar Chemical Process:
Water Detoxification ............................ 110
References 114
Chapter 5. Photovoltaic Cells ................................ 115
Jeannette M. Moore
5.1. Introduction ............................................ 115
5.2. Crystal Structure ....................................... 115
5.3. Cell Physics ............................................ 117
5.4. Energy Bands ............................................ 118
5.5. More about Electrons and Their Energy ................... 119
5.6. Electrons and Holes ..................................... 120
5.7. Direct and Indirect Band-Gap Materials .................. 120
5.8. Doping .................................................. 121
5.9. Transport ............................................... 122
5.10. Generation and Recombination ............................ 122
5.11. The p-n Junction ........................................ 122
5.12. Solar Cell Equations .................................... 124
5.13. Characterization ........................................ 125
5.14. Efficiency .............................................. 127
5.14.1. Temperature .................................... 127
5.14.2. Light .......................................... 129
5.14.3. Type and Purity of Material .................... 129
5.14.4. Parasitic Resistances .......................... 130
5.15. Current Research ........................................ 130
5.15.1. Concentrating Solar Cells ...................... 130
5.15.2. Tandem Cells ................................... 131
5.15.3. Thin Film Technologies ......................... 131
5.15.4. Quantum Dots ................................... 131
5.16. Cell Applications ....................................... 132
5.16.1. Utility Power Generation ....................... 132
5.16.2. Space Systems .................................. 132
5.16.3. Solar-Powered Products ......................... 133
References 133
Problems 133
Chapter 6. Photovoltaic Conversion Systems ................... 135
6.1. Solar Benefits .......................................... 135
6.1.1. Energy Alternatives ............................ 136
6.2. Basic Module Electrical Concepts ........................ 137
6.2.1. PV Electrical Characteristics ................... 137
6.2.2. Common PV Terminology ........................... 138
6.2.3. I-V Curves ...................................... 138
6.3. PV Arrays ............................................... 141
6.3.1. Increasing Voltage .............................. 141
6.3.2. Increasing Current .............................. 142
6.4. PV Array Tilt ........................................... 143
6.5. PV Balance of Systems ................................... 144
6.5.1. Energy Storage .................................. 145
6.5.2. Charge Controllers .............................. 145
6.5.3. Inverters and Converters ........................ 145
6.6. PV System Utility ....................................... 148
6.6.1. Grounding and Bonding DC and AC Circuits ........ 148
6.6.2. Net Metering .................................... 150
6.7. PV System Safety ........................................ 150
6.8. PV System Testing Rules ................................. 150
References .................................................... 151
Problems ...................................................... 151
Chapter 7. Photovoltaic System Sizing and Design ............. 153
7.1. Introduction ............................................ 153
7.2. Solar Resource Sizing Considerations .................... 153
7.3. Solar Trajectory ........................................ 154
7.4. Solar Energy System Sizing Considerations ............... 155
7.5. Solar Energy System Sizing .............................. 156
7.5.1. Example of Simple PV DC System Sizing ........... 156
7.5.2. Sizing Inverters ................................ 157
7.5.2.1. Technical Specifications .............. 158
7.5.2.2. Load Estimation ....................... 158
7.5.2.3. Battery Storage Requirement ........... 158
7.5.2.4. Array Estimation ...................... 159
7.5.2.5. System Summary ........................ 159
7.6. Solar Water Pumping System Sizing ....................... 159
7.6.1. General Method of Sizing a Solar Pump ........... 160
7.7. Generic Water Pump Sizing Methodology ................... 161
7.8. Electrical Codes for PV System Design ................... 164
7.9. Stand-Alone PV Lighting Design Example .................. 169
References .................................................... 172
Problems ...................................................... 172
Chapter 8. Photovoltaic (PV) Applications .................... 173
8.1. Introduction ............................................ 173
8.2. Grid-Tied PV ............................................ 173
8.3. Japanese PV Development and Applications ................ 175
8.3.1. Japanese Government's Approach .................. 178
8.3.2. Japanese PV Utilities ........................... 179
8.3.3. Japanese Marketing .............................. 180
8.3.4. Japanese PV Electrical Code ..................... 181
8.3.5. Japanese PV Design .............................. 182
8.3.6. Japanese PV System Guarantees ................... 184
8.3.7. Japanese PV Development ......................... 184
8.3.8. Japanese PV Module Certification ................ 185
8.4. Future Japanese Trends .................................. 187
8.5. Stand-Alone PV Applications ............................. 188
8.5.1. PV Solar Home Lighting Systems .................. 188
8.5.2. PV Battery Charging Stations .................... 192
8.5.3. PVLS Human Motivation: the Final Driver
of System Success [Guest Authors Debora Ley,
University of Oxford and H. J. Corsair,
The Johns Hopkins University] ................... 195
8.5.4. PV in Xenimajuyu: the Xocoy Family [Guest
Authors Debora Ley, University of Oxford
and H. J.Corsair, The Johns Hopkins
University] ..................................... 196
8.6. PV for Schools .......................................... 197
8.7. PV for Protected Areas .................................. 199
8.7.1. PV Ice-Making and Refrigeration ................. 202
8.7.2. PV Ice-Making ................................... 203
8.8. PV Water-Pumping ........................................ 204
8.8.1. Hydraulic Workloads ............................. 205
8.8.2. Other Considerations ............................ 206
8.8.3. Pressure ........................................ 207
8.8.4. Static Head ..................................... 207
8.8.5. Pumping Requirements ............................ 208
8.8.6. Dynamic Systems ................................. 208
8.8.7. Water Demand .................................... 210
8.8.7.1. Water Resources ....................... 211
8.8.8. Storage of Water versus Storage of Energy
in Batteries .................................... 212
8.8.9. Pumping Mechanisms Used for Solar Pumps ......... 213
8.8.9.1. Centrifugal Pumps ..................... 213
8.8.9.2. Positive Displacement Pumps ........... 213
8.8.9.3. Surface Pumps versus Submersible
Pumps ................................. 214
8.8.10. Types of Motors Used with Solar Pumps ........... 216
8.8.11. Solar Pump Controllers .......................... 217
8.8.11.1. Additional Features of Pump
Controllers ........................... 217
8.8.12. Pump Selection .................................. 218
8.8.13. Installation, Operation, and Maintenance ........ 218
8.8.14. System Installation ............................. 219
8.8.14.1. Civil Works ........................... 220
8.8.14.2. Piping ................................ 221
8.8.14.3. Surface-Pump Installation ............. 221
8.8.14.4. Surface Water Pumps: Preventing
Cavitation and Noise .................. 222
8.8.14.5. Installation of Submersible Pumps ..... 222
8.9. Grounding and Lightning Protection for Solar Water
Pumps ................................................... 222
8.9.1. Bond (Interconnect) All Metal Structural
Components and Electrical Enclosures ............ 223
8.9.2. Ground .......................................... 223
8.9.3. Float Switch Cable .............................. 223
8.9.4. Additional Lightning Protection ................. 224
8.10. Solar Tracking for Solar Water Pumps .................... 224
8.10.1. Passive Trackers ................................ 224
8.10.2. Active Trackers versus Passive Trackers ......... 225
8.11. Operation and Maintenance of the Systems ................ 225
8.12. The PV Array ............................................ 226
8.12.1. Pumps and Motors ................................ 227
8.12.2. Water Supply Systems ............................ 227
8.13. PV Water-Pumping Results .......................... 227
References .................................................... 228
Chapter 9. Economics ......................................... 231
Vaughn Nelson
9.1. Solar Energy Is Free, but What Does It Cost? ............ 231
9.2. Economic Feasibility .................................... 232
9.2.1. PV Costs ........................................ 232
9.3. Economic Factors ........................................ 233
9.4. Economic Analysis ....................................... 233
9.4.1. Simple Payback .................................. 234
9.4.2. Cost of Energy .................................. 235
9.5. Life Cycle Cost ......................................... 236
9.6. Present Value and Levelized Costs ....................... 238
9.6.1. Steps to Determine the LCC ...................... 239
9.7. Annualized Cost of Energy ............................... 240
9.8. Externalities ........................................... 240
9.8.1. Externality Evaluation Methods .................. 241
9.8.2. Societal Perspectives on Solar Energy
Utilization ..................................... 241
9.9. Solar Irrigation Case Study ............................. 242
9.9.1. Estimating System Costs ......................... 242
9.9.2. Table of Approximate Costs ...................... 242
9.9.3. Comparison of Pumping Alternatives .............. 243
9.10. Water Pumping Example ................................... 245
9.11. Summary ................................................. 246
References .................................................... 248
Problems ...................................................... 248
Chapter 10. Institutional Issues .............................. 249
10.1. Introduction ............................................ 249
10.2. Sustainability .......................................... 249
10.3. Institutional Considerations ............................ 250
10.3.1. Policy Issues ................................... 250
10.3.2. Capacity Building ............................... 250
10.3.3. Education and Training .......................... 251
10.3.4. Technical Assistance ............................ 251
10.3.5. Local Infrastructure Development ................ 251
10.3.6. Involving the Community: Sustainability
and Inclusion ................................... 252
10.4. Stakeholders ............................................ 252
10.4.1. Panels versus Fuel or Electric Bills ............ 252
10.4.2. Community Reduction of Theft Risks .............. 253
10.4.3. PV and the "Virtuous Circle" .................... 254
10.5. Program Implementation .................................. 254
10.5.1. Conduct Strategic Planning ...................... 254
10.5.2. Pilot Project Implementation .................... 255
10.5.3. Create Sustainable Markets ...................... 255
10.5.4. Grassroots Development Approach ................. 255
10.5.5. Install Appropriate Hardware .................... 255
10.5.6. Monitoring ...................................... 256
10.6. Institutional Models for Solar Energy Dissemination ..... 256
10.6.1. Cash Sales ...................................... 257
10.6.2. Consumer Financing .............................. 258
10.6.2.1. Revolving Credit Fund ................. 259
10.6.2.2. Local Bank Credit ..................... 259
10.6.3. Leasing ......................................... 259
10.6.3.1. Dealer Credit ........................ 259
10.6.4. Subsidies ....................................... 260
10.7. Management and Ownership ................................ 260
10.7.1. Authorization Arrangement ....................... 260
10.7.2. Contracts ....................................... 260
10.7.3. Leases .......................................... 260
10.7.4. Ownership Transfer (Flip Model) ................. 261
10.7.5. Associations and Cooperatives ................... 261
10.8. Tariffs and Payment ..................................... 261
10.8.1. Free ............................................ 261
10.8.2. Nominal (Subsidized) ............................ 261
10.8.3. Fee for Service ................................. 262
10.8.4. Payment ......................................... 262
10.9. Other Critical Issues ................................... 262
10.10.Summary ................................................. 262
Problems ...................................................... 263
Chapter 11. Energy Storage .................................... 265
11.1. Introduction ............................................ 265
11.2. Batteries in PV Systems ................................. 265
11.2.1. Lead-Antimony Batteries ......................... 266
11.2.2. Lead-Calcium Batteries .......................... 267
11.2.3. Captive Electrolyte Batteries ................... 267
11.2.4. Nickel-Cadmium Batteries ........................ 268
11.3. Lead-Acid Battery Construction .......................... 268
11.3.1. Plate Grids ..................................... 268
11.3.1.1. Positive and Negative Plates .......... 268
11.3.1.2. Separators ............................ 269
11.3.1.3. Elements .............................. 269
11.3.1.4. Cell Connectors ....................... 270
11.3.1.5. Containers ............................ 270
11.3.1.6. Vent Plugs ............................ 270
11.4. Lead-Acid Battery Operation ............................. 270
11.4.1. Discharge Cycle ................................. 271
11.4.2. Charge Cycle .................................... 272
11.4.3. Electrolyte and Specific Gravity ................ 272
11.4.4. Water ........................................... 273
11.4.5. Battery Roundtrip Efficiency .................... 273
11.5. Lead-Acid Battery Characteristics ....................... 273
11.5.1. Ampere-Hour Storage Capacity .................... 273
11.5.2. Battery Cycle Life .............................. 274
11.5.3. Battery Connections ............................. 275
11.6. Battery Problem Areas ................................... 276
11.6.1. Overcharging .................................... 276
11.6.2. Undercharging ................................... 276
11.6.3. Short Circuits .................................. 276
11.6.4. Sulfation ....................................... 277
11.6.5. Water Loss ...................................... 277
11.6.6. Self-Discharge .................................. 278
11.7. Battery Maintenance ..................................... 278
11.7.1. Hydrometer Description and Use .................. 280
11.7.2. Temperature Correction .......................... 280
11.7.3. Tropical Climates ............................... 280
11.8. Battery Safety Precautions .............................. 281
11.8.1. Battery Acid .................................... 283
11.8.2. Hydrogen Gas .................................... 283
11.8.3. Battery Enclosures .............................. 284
11.9. Determination of Battery Failure ........................ 284
11.9.1. Battery Applications and Installation ........... 284
11.9.2. Battery Service History ......................... 284
11.9.3. Visual Inspection ............................... 286
11.9.4. Battery Age ..................................... 286
11.9.5. Overcharging and Undercharging .................. 286
11.9.6. Internal Examination ............................ 287
11.9.7. Container ....................................... 287
11.9.8. Electrolyte ..................................... 287
11.10.Battery Selection Criteria .............................. 287
11.10.1.Battery Procurement Considerations .............. 288
11.10.1.1.Additional Battery Manufacturer
Specifications ....................... 288
11.10.2.Additional Battery System Considerations ........ 289
11.10.2.1.Small-System Considerations ........... 289
11.10.2.2. Large-System Considerations ......... 289
11.11.Charge Controller Terminology ........................... 289
11.12.Charge Controller Algorithms ............................ 290
11.12.1.Shunt Controller ................................ 290
11.12.2.Series Controller ............................... 291
11.13.Charge Controller Selection Criteria .................... 292
11.13.1.Charge Controller Procurement Specifications .... 292
11.13.1.2.Additional Charge Controller
Manufacturer Specifications ........... 292
References .................................................... 293
Problems ...................................................... 293
Solar Energy Glossary ......................................... 295
Batteries ..................................................... 295
Electricity ................................................... 298
Photovoltaics ................................................. 300
Solar Energy Concepts ......................................... 302
Solar Water-Pumping ........................................... 303
Appendix A: World Insolation Data ............................. 307
Appendix B: Friction Loss Factors ............................. 327
Appendix C: Present Value Factors ............................. 331
Appendix D: Table of Approximate PV Pumping-System Costs ...... 335
Index ......................................................... 337
|
