Introduction 1
About This Book 1
Conventions Used in This Book 2
What Youâre Not to Read 3
Foolish Assumptions 3
How This Book Is Organized 3
Part 1: Here Comes the Sun: Shedding Some Light on PV Systems 4
Part 2: Digging into Complete System Details 4
Part 3: Sizing a PV System 4
Part 4: Installing a PV System 4
Part 5: The Part of Tens 5
Icons Used in This Book 5
Where to Go from Here 5
Part 1: Here Comes the Sun: Shedding Some Light on PV Systems 7
Chapter 1: The Photovoltaic Revolution 9
Peeking into the Past, Present, and Future of PV Installations 9
Acquainting yourself with typical PV applications 10
Checking out PV pros and cons 10
Looking into the future of PV 11
Introducing PV Components and Systems 11
Knowing Your Electricity A-B-Cs 12
Solar Resource 101 13
Surveying a PV System Site 13
Delving into PV System Details 14
PV modules 14
Batteries 14
Charge controllers 15
Inverters 15
Wiring and safety devices 15
Sizing a PV System 16
Grid-direct systems 16
Battery-based systems 16
Conductors and safety devices 17
Bringing a PV System to Life 17
Permitting 17
Staying safe 17
Putting together the mechanical parts 18
Adding the electrical parts 18
Commissioning, inspecting, and maintaining a system 19
Introducing the Sections of Code You Need to Know 20
Chapter 2: Checking Out Common Components and Systems 21
Introducing the Components That Make Up PV Systems 21
PV modules and racking 22
Battery bank 23
Charge controller 24
Inverter 24
Loads 25
Load centers 26
Disconnects and overcurrent protection 27
Utility interconnection 27
Differentiating between PV System Types 29
Grid-direct systems 29
Battery-based systems 31
Figuring Out the Right System Type for Any Situation 34
The customer is connected to the grid 34
The customer isnât connected to the grid 35
Chapter 3: Powering through Electricity Basics 37
Going with the Flow: Current 38
Understanding amps 38
Distinguishing between direct current and alternating current 39
Measuring current with a meter 40
May the (Electromotive) Force Be with You: Voltage 43
Grasping the concept of voltage 43
Getting a grip on nominal voltage and operating voltage 43
Measuring voltage 44
Making a Stop: Resistance 46
Introducing ohms 47
Measuring resistance 47
Connecting Current, Voltage, and Resistance with Ohmâs Law 49
Pondering Power and Energy 50
Recognizing the differences between power and energy 50
Relating power to current, voltage, and resistance with the power equation 51
Calculating energy in terms of watt-hours 53
Introducing amp-hours, a companion to watt-hours 53
Wrapping Together Current, Voltage, Resistance, Power, and Energy 54
Another Electricity Concept: Circuit Configurations 55
Series 56
Parallel 57
Series-parallel 58
Chapter 4: Warming Up to the Solar Resource 59
High (Or Low) Energy: Solar Radiation 60
Distinguishing between direct radiation and diffuse radiation 60
Determining the intensity of solar radiation: Irradiance 61
Calculating solar radiation energy: Irradiation 65
Just for a day: Peak sun hours 66
Examining the Effects of the Sunâs Path on the Earth 69
Getting a grip on seasonal effects 70
Understanding the sunâs relationship to your location: Altitude and azimuth 72
Ticking off solar time 74
Interpreting sun charts 74
Opening up to the solar window 76
Positioning PV Modules to Make the Most of the Solar Resource 77
Introducing tilt angle 77
Orienting your array to the azimuth 79
Chapter 5: Properly Selecting a Site for a PV System 81
Setting the Stage for a Site Survey 82
Putting aside enough time 82
Creating a standard site-survey form 83
Toting a site-survey bag 83
Picture This: Documenting Your Entire Site Survey with Digital Photos 84
Collecting Basic Information during a Site Survey 86
General site information 86
Structural and mechanical information 87
Electrical information 89
Measuring Information in Degrees 90
Understanding magnetic declination 91
Calculating the arrayâs tilt angle and azimuth 93
Exploring Shading-Analysis Tools 95
Interpreting the Data and Bringing It All Together 97
Analyzing reports from your shading-analysis tool 98
Considering the total solar resource factor 98
Using other collected information to plan out the design and installation 100
Part 2: Digging Into Complete System Details 103
Chapter 6: PV Modules: From Sand to Electricity 105
Creating Solar Electricity: It All Starts with a Cell 106
Getting a grip on cell construction and manufacturing 106
Connecting cell construction to the photovoltaic effect 108
Reviewing Common Types of PV Modules 108
Checking out crystalline modules 109
Looking at thin film modules 111
Pointing Out Electrical Specifications on PV Modules 113
Current specifications 114
Voltage specifications 115
Maximum power point 116
Voltage temperature coefficient 117
Power tolerance 118
Series fuse rating 118
Surveying Test Conditions for PV Modules 118
Standard test conditions 119
Environmental effects on standard test conditions 120
Relating Current and Voltage in IV Curves 122
An IV curve with varying temperature 123
An IV curve with varying irradiance 124
Chapter 7: The Basics of Batteries 127
The Fundamentals of Battery Anatomy and Operation 128
Constructing a battery, from cell to bank 128
Discovering how batteries charge and discharge 130
Comparing Different Types of Batteries 133
Lead-acid batteries 133
Lead-calcium batteries 136
Nickel-cadmium batteries 136
Comprehending Battery Capacity 137
Considering the C rate for capacity 137
Recognizing factors that affect capacity 138
Specifying Batteries 141
Specifying the type of battery to use 141
Specifying the battery bank size 142
Chapter 8: Keeping Current and Voltage in Check: Charge Controllers 147
The Essentials of Charge Controllers 148
Seeing how a charge controller works in stages 148
Surveying special effects provided by some charge controllers 151
Maximum Power Point Tracking Technology 153
How MPPT works 153
The pros and cons of MPPT controllers 154
Pulse-Width Modulation Technology 155
How PWM works 155
The pros and cons of PWM controllers 156
Specifying a Charge Controller 156
Chapter 9: Inverters: AC (From) DC 157
Getting the Goods on Grid-Direct Inverters 158
Basic operation 158
Standard features 159
Power output sizes 162
The importance of transformers 162
Investigating Battery-Based Inverters 164
Utility-interactive inverter operation 165
Stand-alone inverter operation 166
Standard features for all battery-based inverters 167
Sizes of battery-based inverters 168
Low-frequency transformer technology 168
Specifying Any Inverter 168
Grid-direct 169
Battery-based 170
Chapter 10: Staying Secure: Wiring and Safety Components 173
Defining the Circuits in a PV System 174
Checking Out Types of Conductors 175
USE-2 176
PV wire 176
Building wiring 177
Battery wiring 178
Ground wiring 178
Considering Kinds of Conduit 179
Metallic conduit 179
Nonmetallic conduit 180
Delving into Disconnects 181
Perusing Overcurrent Protection Devices 182
Circuit breakers 183
Fuses 183
Focusing on Ground Fault Protection 184
Looking at the Basics of Labels 185
Part 3: Sizing a PV System 187
Chapter 11: Sizing a Grid-Direct System 189
First Things First: Evaluating the Budget and the Available Array Area 190
Estimating the Siteâs Annual Energy Production 191
Sizing the Array to Meet Your Clientâs Energy Consumption 193
Determining annual energy consumption 193
Looking at contract options with the utility 194
Using consumption and contract options to select an arrayâs needed power value 195
Getting Ready to Match an Inverter to an Array 196
Matching Power Values for an Array and an Inverter 197
Coming Up with the Right Voltage Values for Your Array and Inverter 199
Establishing the inverterâs AC voltage 200
Defining the inverterâs DC voltage window 200
Calculating the modulesâ maximum DC voltage contribution 201
Figuring out the modulesâ minimum DC voltage contribution 208
Bringing It All Together: Combining Your Power and Voltage Information 213
One Last Check: The Inverterâs Maximum Current Input 214
Chapter 12: Sizing a Battery-Based System 215
Get Loaded: Looking at Loads in a Battery-Based System 216
Evaluating the loads that the battery bank must serve 216
Calculating the energy required during an outage for utility-interactive systems 219
Determining the average daily energy consumption for stand-alone systems 219
Sizing the Battery Bank 222
Inverter efficiency 222
The days of autonomy 223
The temperature used for battery operation 223
The depth of discharge 224
Nominal voltages 225
Figuring out the battery capacity you need 226
Strung along: Wiring the battery bank 227
Sizing the PV Array 229
Sizing the array in a utility-interactive system 229
Sizing the array in a stand-alone system 230
Sizing the Charge Controller 232
Voltage specifications 233
Power or amperage specifications 234
A check before you move on: Comparing the array size to the battery capacity 236
Sizing the Inverter 236
Viewing voltage output 237
Calculating the power draw 237
Staying in charge 238
Looking at surge ratings 238
Evaluating inverter and array power output 239
Incorporating a Generator 239
Generator features 240
Generator sizing 241
Chapter 13: Sizing Conductors, Conduit, and Safety Components 243
Conductor Sizing 101 244
Defining the PV circuitsâ maximum and continuous current 245
Calculating non-PV circuitsâ maximum current 246
Considering conditions of use with some handy tables 247
Putting together the details to determine conductor sizing 250
Accounting for voltage drop after you size your conductors 253
Sizing Conduit 257
Sizing Overcurrent Protection Devices and Disconnects 258
Beginning with a few basics 258
Placing protection on PV circuits 259
Protecting inverter circuits 260
Part 4: Installing a PV System 261
Chapter 14: The Permitting Process 263
Obtaining Permits before You Install a PV System 263
In the beginning: Having the right licenses and certifications 264
Home grown: Permitting for residential systems 265
Big business: Permitting for commercial systems 269
Not Just Pretty Pictures: Creating Drawing Sets 272
Calling out components clearly 273
Depicting equipment locations 273
Showing conductor-sizing calculations 273
Jotting down job notes 274
Chapter 15: Staying Safe Anytime You Work on a PV System 275
Getting a Grip on General Construction Site Safety 276
Identifying job-site obstacles and putting on protective gear right away 276
Safely working alone and with others 277
Taking in tips for tool safety 278
Limiting your exposure to the elements 278
Stowing a first-aid kit on the job site 279
Looking at Ladder Safety 279
Selecting your stash of ladders 279
Properly setting up any ladder 281
Raising the Issue of Rooftop Safety 282
Restraining yourself with fall protection 283
Storing your tools 283
Maintaining safe walkways 285
Examining Electrical Safety 285
Staying aware of general shock hazards 285
Working with circuits 286
Charging Ahead with Battery Safety 290
Chapter 16: Assembling the Mechanical Parts 293
Surveying PV Array Mounting Methods 294
Roof mounting 295
Ground mounting 300
Top-of-pole mounting 302
Building-integrated mounting 303
Considering Loading When You Mount an Array on a Roof 305
Following building codes 305
Accounting for additional dead load 305
Looking at live loads 307
Properly Attaching an Array to a Roof 309
Making attachments with lag screws 309
Sealing roof penetrations with flashing 310
Supporting Ground and Top-of-Pole Mounting 313
Chapter 17: Integrating the Electrical Elements 315
Location Is Everything: Knowing Where to Place Electrical Equipment 316
Manufacturersâ requirements for equipment locations 316
Locations for disconnecting means 317
Combiner boxes and junction boxes and wiring, oh my! 318
Working on Wiring 319
Seeing red (and green and white): Color-coding 319
Managing wires on PV modules 321
Protecting wires with conduit 322
Bonding Yourself to Grounding 323
Equipment grounding 323
System grounding 326
Connecting to the Utility 329
Determining the utilityâs requirements 329
Making a load side or line side connection 331
Chapter 18: Commissioning, Inspecting, and Maintaining a PV System 335
Making a List and Checking It Twice: Preparing for Commissioning 336
Mechanical elements? Check! 336
Electrical elements? Check! 337
Start âEr Up: The Commissioning Process 341
Putting safety first 342
Gathering the gear you need 342
Commissioning different types of systems 343
Verifying that the system is working 347
Arming Yourself for Inspection Issues 349
Not having âa neat and workmanlike mannerâ 350
Forgetting about aesthetics 350
Failing to manage conductors on the array 350
Neglecting to label the system 351
Surveying System Maintenance 353
Mechanical maintenance 354
Electrical maintenance 354
Maintenance on a higher level: Taking care of battery banks 355
Part 5: The Part of Tens 359
Chapter 19: Ten Ways to Avoid Common Code Mistakes 361
Providing Proper Working Clearance 362
Supplying the Right Structural Support 362
Keeping Water out of Buildings with Flashing 363
Ensuring All Conductors Have the Necessary Ratings 363
Managing the Conductors on Modules 364
Selecting the Correct Conduit 364
Locating the Disconnects 365
Grounding the Equipment 365
Grounding the System 366
Labeling the System Properly 366
Chapter 20: Ten Ways to Maximize Energy Production for Your Clients 367
Select the Right Site 367
Orient the Array Correctly 368
Configure the Array Properly 368
Work within the Limits of the Utility Voltage 369
Choose the Correct Inverter 369
Size Conductors Appropriately 370
Keep the Components Cool 370
Advise Clients to Monitor Their System 371
Clean the Array Periodically 371
Inspect the Array Annually 372
Index 373
