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Photovoltaic Laboratory

Book Description

Photovoltaic Laboratory: Safety, Code-Compliance, and Commercial Off-the-Shelf Equipment is the only textbook that offers students the opportunity to design, build, test, and troubleshoot practical PV systems based on commercially available equipment. Complete with electrical schematics, layouts, and step-by-step installation instructions, this hands-on laboratory manual:

  • Promotes "safety first" by covering working in extreme weather conditions, personal protective equipment, working at heights, electrical safety, and power tool safety
  • Includes chapters on trade math, DC/AC electrical circuits, and assessing a property for a photovoltaic system (e.g., surveying the available space, shading, and solar harvest)
  • Discusses aspects of mechanical and electric integration specific to different roof types, and characterizing a PV module under different levels of irradiation and ambient temperature
  • Addresses the design, installation, and testing of off-grid PV systems with DC-only loads and with DC and AC loads, as well as 2.4 kw DC grid-tied PV systems with microinverters and string inverters
  • Trains students on exactly the sort of equipment that they will encounter in the field, so they gain valuable experience and skills that translate directly to real-world applications

Photovoltaic Laboratory: Safety, Code-Compliance, and Commercial Off-the-Shelf provides in-depth, project-driven instruction on everything from attaching brackets and flashing to modeling PV cells, modules, and arrays. This textbook is ideal preparation for those seeking a career in the PV industry—from system installers and designers to quality assurance and sales/marketing personnel.

Table of Contents

  1. Preface
  2. Acknowledgments
  3. Introduction
  4. How to Use This Textbook
  5. The Author
  6. Chapter 1 - Safety
    1. 1.1 Introduction
    2. 1.2 Student Learning Objectives
    3. 1.3 Working in Extreme Weather Conditions
      1. 1.3.1 The Hot, Dry Climate
      2. 1.3.2 The Cold Climate
    4. 1.4 Understanding Heat Stress
      1. 1.4.1 Heat Exhaustion—Symptoms and Appropriate Responses
      2. 1.4.2 Heat Stroke—Symptoms and Appropriate Responses
      3. 1.4.3 Dehydration—Symptoms and Appropriate Responses
      4. 1.4.4 Hypothermia—Symptoms and Appropriate Responses
      5. 1.4.5 Frostbite—Symptoms and Appropriate Responses
      6. 1.4.6 Preventing Heat or Cold Stress
    5. 1.5 General Safety Training
    6. 1.6 Personal Protective Equipment (PPE)
      1. 1.6.1 Eye Protection and Gloves
      2. 1.6.2 Protective Helmets (a/k/a Hard Hats)
      3. 1.6.3 Aprons
      4. 1.6.4 Footwear
    7. 1.7 Working at Heights
      1. 1.7.1 Safety Barriers
      2. 1.7.2 Guardrail Systems
      3. 1.7.3 Safety Netting
      4. 1.7.4 Personal Fall Arrest: Body Harnesses
      5. 1.7.5 Rescue Plan
      6. 1.7.6 Ladders and Ladder Safety
    8. 1.8 Electrical Safety
      1. 1.8.1 Overhead Power Lines
      2. 1.8.2 Operating Electrical Equipment
    9. 1.9 Moving and Carrying Heavy Objects
    10. 1.10 Roofs and Attics
    11. 1.11 Lockout/Tagout
    12. 1.12 Safety Posters
    13. Notes
  7. Chapter 2 - Trade Math for PV—Measurements, Units, and Calculations
    1. 2.1 Introduction
    2. 2.2 Student Learning Objectives
    3. 2.3 The Decimal System of Notation
    4. 2.4 Scientific Notation (Exponential Notation [Base 10])
    5. 2.5 Adding, Subtracting, Multiplying, and Dividing in SN
      1. 2.5.1 Multiplication and Division
      2. 2.5.2 Addition and Subtraction
      3. 2.5.3 Metric System and Prefixes
      4. 2.5.4 Nonstandard Units of Measure
        1. 2.5.4.1 The British Thermal Unit (BTU)
        2. 2.5.4.2 The Kilowatt Hour (kWh)
        3. 2.5.4.3 The BTU—A Diversion
      5. 2.6.1 A–B Comparison
      6. 2.6.2 Change of a Value (over Time)
    6. 2.7 Student Exercises
      1. 2.7.1 A–B Comparison
    7. 2.8 Significant Digits and Precision
    8. 2.10 Basic Algebra
      1. 2.10.1 Ohm’s Law
      2. 2.10.2 Watt’s Law
      3. 2.10.3 Order of Operations
    9. 2.11 Trigonometry of Right Triangles
      1. 2.11.1 The Right Triangle
      2. 2.11.2 The Pythagorean Theorem
      3. 2.11.3 Calculations Involving the Pythagorean Theorem
      4. 2.11.4 The Three Trigonometric Functions
      5. 2.11.5 Evaluating the Angle θ and Inverse Trigonometric Functions
      6. 2.11.6 Reciprocal Trigonometric Functions
    10. 2.12 Length, Area, and Volume
    11. 2.13 The Celestial Sphere
    12. 2.14 Analyzing Word Problems
    13. 2.15 Mastering the Use of a Calculator
      1. 2.15.1 Addition and Subtraction
      2. 2.15.2 Multiplication and Division
      3. 2.15.3 Trigonometry
  8. Chapter 3 - Measurements of DC and AC Electrical Circuits
    1. 3.1 Introduction
      1. 3.1.1 DC Electrical Circuits
      2. 3.1.2 AC Electrical Circuits
    2. 3.2 Student Learning Objectives
    3. 3.3 Setup
      1. 3.3.1 The Calculator
      2. 3.3.2 Electrical Components
      3. 3.3.3 Measurement Instruments
      4. 3.3.4 Other Equipment
    4. 3.4 The DC Electrical Circuit—An Abstraction
    5. 3.5 Basic Electrical Concepts—Analogy with Water Flow
      1. 3.5.1 Charge
      2. 3.5.2 Current
      3. 3.5.3 Current Continuity
      4. 3.5.4 Voltage
      5. 3.5.5 Resistance
      6. 3.6.1 Power
      7. 3.6.2 Energy
      8. 3.6.3 Time and Frequency
    6. 3.7 Summary of Circuit Concepts
    7. 3.8 Nominal Specifications
    8. 3.9 DMM Measurement Accuracy
    9. 3.11 Student Exercises
      1. 3.11.1 Measuring the Voltage Standard
    10. 3.12 Color Coding for Resistors
    11. 3.13 Measuring Resistance with the DMM
    12. 3.14 Measuring DC Voltage with the DMM
      1. 3.14.1 Single Batteries
      2. 3.14.2 Multiple Batteries—In Series and in Parallel
    13. 3.15 Bench Power Supply
    14. 3.16 Powering a 12 V LED
    15. 3.17 Powering a 10 Ω, 50 W Resistor
    16. 3.18 AC Circuit Theory
      1. 3.18.1 What Is a Sinusoidal Signal?
    17. 3.19 Electrical Utility Service
    18. 3.20 Measuring a 120/240 VAC 200A Split-Phase Service Panel
      1. 3.20.1 120 VAC Branch Circuit (L1 or L2)
      2. 3.20.2 240 VAC Branch Circuit (L1 and L2)
      3. 3.20.3 Measuring Current in a 120 VAC Branch Circuit
    19. Notes
  9. Chapter 4 - The Site Survey
    1. 4.1 Introduction
    2. 4.2 Student Learning Objectives
    3. 4.3 Organization of This Lab
    4. 4.4 Prior Activities
      1. 4.4.1 Preliminary Technical Sales Proposal
      2. 4.4.2 Sample Module Rows
      3. 4.4.3 Determination of All Authorities Having Jurisdiction (AHJs)
      4. 4.4.4 The Virtual Site Survey
    5. 4.5 Resources
    6. 4.6 Example of a Site Survey
      1. 4.6.1 County Assessor’s Map
      2. 4.6.2 Sketch of the Property Including House
      3. 4.6.3 Documentation of Roof Sections
      4. 4.6.4 Site Survey Document
    7. 4.7 Student Exercises
      1. 4.7.1 Student Site Survey
        1. 4.7.1.1 Document the Roof
      2. 4.7.2 Rafter/Truss and Attic Details
        1. 4.7.2.1 Attic Inspection
      3. 4.7.3 Main Service Panel
      4. 4.7.4 Use of a Subpanel
      5. 4.7.5 Locations for Other Major Components
      6. 4.7.6 Grounding of Electrical Service
      7. 4.7.7 Trenching
    8. 4.8 Shading Analysis
      1. 4.8.1 Performing a Manual Shading Analysis Using the SolarPathfinder
      2. 4.8.2 Performing an Advanced Shading Analysis Using the SolarPathfinder
      3. 4.8.3 Performing a Shading Analysis Using the Solmetric SunEye®
    9. 4.9 Summary
    10. Notes
  10. Chapter 5 - Racking Systems—General Considerations
    1. 5.1 Introduction
    2. 5.2 Student Learning Objectives
    3. 5.3 Setup
      1. 5.3.1 Portrait versus Landscape Layouts
    4. 5.4 Positioning the Rails and Brackets
      1. 5.4.1 The 25% and 75% Rule
      2. 5.4.2 Maximum Bracket Spacing
      3. 5.4.3 Standard Residential Rafter/Truss Spacing
      4. 5.4.4 Constraints on Portrait Orientation
      5. 5.4.5 Constraints on Landscape Orientation
      6. 5.4.6 Case Study: The 60-Cell, 156 mm Square Cell PV Module
    5. 5.5 Design of Layout for a Single PV Module
    6. 5.6 Small Mock Roof Details
    7. 5.7 Locating the Rafters
    8. 5.8 Pull-Out Strength of Lag Bolts
    9. 5.9 Wind Forces on Roofs
      1. 5.9.1 The “Simple” Approach
    10. 5.10 Student Exercises
      1. 5.10.1 Model Structures
        1. 5.10.1.1 Calculations Based on Simple Approach
        2. 5.10.1.2 Calculations Based on Complicated Approach
      2. 5.10.2 Roof-Specific Installation of Brackets
    11. Notes
    12. 5A.1 Introduction
    13. 5A.2 Student Learning Objectives
    14. 5A.4 Setup
    15. 5A.5 Tools Needed for This Lab
    16. 5A.6 Student Exercises
      1. 5A.6.1 Design Layout for a Single PV Module
    17. 5A.7 Locating the Rafters
      1. 5A.7.1 Begin Layout
      2. 5A.7.2 Installing the Brackets
      3. 5A.7.3 Choice of Post
      4. 5A.7.4 Installing Flashing
      5. 5A.7.5 Dimensioning and Attaching the Rail
      6. 5A.7.6 Installing the PV Module
    18. Appendix 5B: Racking Systems on Flat Concrete Tile Roofs
    19. 5B.1 Introduction
    20. 5B.2 Student Learning Objectives
    21. 5B.4 Setup
    22. 5B.5 Tools Needed for This Lab
    23. 5B.6 Student Exercises
      1. 5B.6.1 Locating the Rafters
        1. 5B.6.1.1 Begin Layout
        2. 5B.6.1.2 Removing Tiles and Precision Location of Rafters
        3. 5B.6.1.3 Setting the Brackets
        4. 5B.6.1.4 Positioning the Rails
    24. 5B.7 The PV Module
  11. Chapter 6 - Characterization of a PV Module
    1. 6.1 Introduction
    2. 6.2 Student Learning Objectives
    3. 6.3 Setup
      1. 6.3.1 The TiltAll Tripod
      2. 6.3.2 Choice of PV Module—The Renogy RNG-100D
    4. 6.4 Components and Instruments
      1. 6.4.1 The Gnomon
      2. 6.4.2 Digital Multimeter (DMM)
      3. 6.4.3 Bead Wire Thermocouple and Black Electrician’s Tape
      4. 6.4.4 Clamp-On Ammeter
      5. 6.4.5 Digital Infrared Thermometer
      6. 6.4.6 Irradiance Meter
      7. 6.4.7 Tilt Meter
      8. 6.4.8 Torpedo Level
      9. 6.4.9 Thermometer
      10. 6.4.10 Calculator
    5. 6.5 Student Exercises
      1. 6.5.1 The Measurements
        1. 6.5.1.1 Measurement 1: Maximum Irradiance
        2. 6.5.1.2 Measurement 2: The Gnomon and Measuring the Angle of Incidence
        3. 6.5.1.3 Measurement 3: Irradiance When PV Module Is Pointing Directly at the Sun
        4. 6.5.1.4 Measurement 4: Irradiance When the PV Module Is Not Pointed at the Sun
        5. 6.5.1.5 Measurement 5: Module Temperature—Two Ways to Measure
        6. 6.5.1.6 Measurement 6: Ambient Temperature
        7. 6.5.1.7 Measurement 7: Standard Operating Conditions (SOCs) and Nominal Operating Cell Temperature
        8. 6.5.1.8 Measurement 8: Voc , the Open Circuit Voltage
        9. 6.5.1.9 Measurement 9: Isc, the Short Circuit Current
        10. 6.5.1.10 Measurement 10: The Full I-V Characteristic
        11. 6.5.1.11 Measurement 11: Maximum Power Point, Pmax
      2. 6.5.2 Other Minor Dependencies
  12. Chapter 7 - Modeling the PV Cell, Module, and Array
    1. 7.1 Preface
      1. 7.1.1 The “Standard Methodology”
      2. 7.1.2 Universal Constants: Cell Voltage and Cell Current Density
      3. 7.1.3 Partial Shading of PV Modules and Bypass Diodes
      4. 7.1.4 Overcurrent Protection in Three or More Strings
      5. 7.1.5 High-Performance PV Modules
    2. 7.2 Unity in the Data?
      1. 7.2.1 How Many Cells in a Module?
      2. 7.2.2 Commercial PV Module Electrical Characteristics
    3. 7.3 Goals for This Laboratory
    4. 7.4 Introduction
    5. 7.5 Student Learning Objectives
    6. 7.6 Simple Component Models in PSpice
      1. 7.6.1 The Resistor Revisited
      2. 7.6.2 The Voltage Source
      3. 7.6.3 The Current Source
      4. 7.6.4 The Diode
      5. 7.6.5 Plotting the Diode I-V Characteristic
    7. 7.7 Two-Element Model for the PV Cell
      1. 7.7.1 I-V Characteristic for the PV Cell
      2. 7.7.2 The Concept of Load Resistance
      3. 7.7.3 Separately Displaying the Source, Diode, and External Load Currents
      4. 7.7.4 Maximum Power Point (MPP)
    8. 7.8 Cell Efficiency
    9. 7.9 I-V and P-V Characteristics for Different Irradiance Values
      1. 7.10.1 Temperature Dependence of PV Cell Characteristics—Voc
      2. 7.10.2 Temperature Dependence of PV Cell Characteristics—Isc
    10. 7.11 Student Exercises
    11. 7.12 The PSpice Simulation Program
    12. 7.13 The Spice Netlist
      1. 7.13.1 Creating the Netlist Using MS Notepad
      2. 7.13.2 Using MS Excel to Record and Plot Data
    13. 7.14 Using the Power of PSpice
      1. 7.14.1 Using the Voltage Source in Place of the Load Resistor
      2. 7.14.2 The New Netlist
      3. 7.15.1 Adding the Parasitic Resistances
      4. 7.15.2 Library Element “cell_1.lib”
    14. 7.16 The Effects of Shading at the Cell Level
    15. 7.17 Optional Exercises
  13. Chapter 8 - Lead-Acid Absorbent Glass Mat Batteries
    1. 8.1 Introduction
    2. 8.2 Student Learning Objectives
    3. 8.3 Overview of Lead-Acid Batteries
    4. 8.4 Markets for Pb-Acid Batteries
      1. 8.4.1 The Automotive Market
      2. 8.4.2 Conventional Traction Market
      3. 8.4.3 Energy Storage Market
      4. 8.4.4 Lead Alloys
    5. 8.5 Comparison with Other Battery Technologies
    6. 8.6 Characterizing the Pb-Acid Battery
      1. 8.6.1 Nominal Battery Voltages
      2. 8.6.2 Battery Capacity
      3. 8.6.3 State of Charge and Depth of Discharge
      4. 8.6.4 More on Battery Capacity
      5. 8.6.5 Expected Life Cycles
      6. 8.6.6 Three-Stage Charging
    7. 8.7 Student Exercises
      1. 8.7.1 Charging the PVX-840T
    8. 8.8 Discharging the PVX-840T
    9. Notes
  14. Chapter 9 - Off-Grid PV System with DC-Only Loads
    1. 9.1 Introduction
    2. 9.2 Student Learning Objectives
    3. 9.3 Overall Design Philosophy
    4. 9.4 The Load Profile
    5. 9.5 Days of Autonomy and Battery Energy Capacity
      1. 9.5.1 Measuring the Depth of Discharge
    6. 9.6 PV System Rating
      1. 9.7.1 Charge Controller Efficiency
      2. 9.7.2 Charging/Discharging Efficiency of AGM Battery
      3. 9.7.3 Depth of Discharge and Life Cycles
    7. 9.8 Student Exercises
      1. 9.8.1 Load Profile Calculation
    8. 9.9 Days of Autonomy
    9. 9.10 Total Energy Requirement
    10. 9.11 Charging/Discharging Efficiency of AGM Battery
    11. 9.12 Charging Efficiency of Charge Controller
    12. 9.13 Required Energy Storage in Battery
    13. 9.14 Required Energy Delivery by PV System
    14. 9.15 PV Subsystem Simulation
    15. 9.16 Document Final System Configuration
    16. 9.17 Balance of System Components and Conductor Sizing
    17. 9.18 Battery Current
    18. 9.19 PV Circuit Conductors
    19. 9.20 Electrical Schematic and System Layout
    20. 9.21 Layout
    21. 9.22 The Pick List
    22. 9.23 Mounting the System Components
    23. 9.24 Documenting the Final System
      1. 9.24.1 System Certification
      2. 9.24.2 Photographs
    24. 9.25 System Documentation
      1. 9.25.1 System Schematic
      2. 9.25.2 System Layout
      3. 9.25.3 System Certification Sheet
      4. 9.25.4 Photograph of Integrated System
    25. Note
  15. Chapter 10 - Off-Grid PV System with DC and AC Loads
    1. 10.1 Introduction
    2. 10.2 Student Learning Objectives
    3. 10.3 Overall Design Philosophy
      1. 10.3.1 AC Loads
      2. 10.3.2 DC Loads
      3. 10.3.3 DC-to-DC Converters
      4. 10.3.4 The Load Profile
      5. 10.3.5 PV System Sizing
      6. 10.3.6 Days of Autonomy
      7. 10.3.7 Number of Battery Cycles
    4. 10.4 System Calculations
    5. 10.5 Student Exercises
      1. 10.5.1 Load Profile Calculations
      2. 10.5.2 Days of Autonomy
      3. 10.5.3 Total Energy Requirement
      4. 10.5.4 Sizing the Battery Subsystem
      5. 10.5.5 Sizing the PV Module and Charge Controller
      6. 10.5.6 PV Subsystem Simulation
      7. 10.5.7 Document the Final System Configuration
      8. 10.5.8 Electrical Schematic and System Layout
      9. 10.5.9 System Layout
      10. 10.5.10 Mounting System Components
    6. 10.6 Documenting the Final System
      1. 10.6.1 Electrical Schematic
      2. 10.6.2 Physical Layout
      3. 10.6.3 Certification Measurements
      4. 10.6.4 Photographs
    7. 10.7 Owner’s Manual
  16. Chapter 11 - 2.4 kW DC Grid-Tied PV System with Microinverters
    1. 11.1 Introduction
    2. 11.2 Student Learning Objectives
    3. 11.3 Setup
      1. 11.3.1 The Roof
      2. 11.3.2 Racking Equipment
      3. 11.3.3 Choice of PV Module
      4. 11.3.4 Choice of Microinverter
      5. 11.3.5 Simulation of PV Performance and Monitoring
      6. 11.3.6 Personal Protective Equipment
      7. 11.3.7 Materials and Tools
    4. 11.4 High-Level Design
      1. 11.4.1 Estimated Consumption Based on Electricity Bill History
      2. 11.4.2 Estimated Consumption Based on Square Footage of Living Space
      3. 11.4.3 Estimated Consumption Based on Load Profile
      4. 11.4.4 System Size for This Laboratory
    5. 11.5 Site Assessment
      1. 11.5.1 Perform Shading Analysis
      2. 11.5.2 Final PV Module Layout
    6. 11.6 Roof Loading Calculations
    7. 11.7 Mechanical Loading—The Live and Dead Loads
      1. 11.7.1 Live Loads
      2. 11.7.2 Dead Loads—PV System and Roof
      3. 11.7.3 Dead Load of the Roof Material
      4. 11.7.4 The Total Dead Load
      5. 11.7.5 Calculation of Maximum Horizontal Span of a Roof Rafter
    8. 11.8 Wind Loading
      1. 11.8.1 Design Wind Pressure for the Site
      2. 11.8.2 The SolarMount Code-Compliant Installation Manual 227.3
      3. 11.8.3 Basic Equation for Design Wind Loading for Components and Cladding
        1. 11.8.3.1 Additional Information Needed
      4. 11.8.4 Total Design Load (Downforce and Uplift)
      5. 11.8.5 Calculating Uplift Force on Each Standoff and Comparing to Pullout Strength of Fasteners
      6. 11.8.6 The Concept of Design (Safety) Margin
    9. 11.9 Fire Marshal Setbacks
    10. 11.10 Layout of PV System
    11. 11.11 Single-Line and Four-Line Diagrams
      1. 11.11.1 A Single-Line Diagram
      2. 11.11.2 A Four-Line Diagram
      3. 11.11.3 National Electrical Manufacturers Association
      4. 11.11.4 Underwriters Laboratory
      5. 11.11.5 The Difference between Four-Line and Single-Line Diagrams
      6. 11.12.1 Sketch of Layout in Notebook
      7. 11.12.2 Transfer Sketch to Roof
      8. 11.12.3 Attach Standoffs, Flashing, Rails, and AC Cable
      9. 11.12.4 Documenting the Mechanical Subsystem—Standoffs, Flashing, and Rails Inputs from Roof Details—Optional
      10. 11.13.1 The First Row
    12. 11.14 The Installation Map Monitoring System
    13. 11.15 Installing Balance of System
    14. 11.16 Lightning and Surge Protection
    15. 11.17 Installing the Enphase Monitoring System
      1. 11.17.1 Connecting the Gateway to Enphase Internet Site
    16. 11.18 Energizing the System
    17. 11.19 Activating the System
    18. 11.20 Certification Testing
    19. 11.21 Troubleshooting
      1. 11.21.1 Post-Start-Up LED Indications
    20. Notes
  17. Chapter 12 - 2.4 kW DC Grid-Tied PV System with String Inverter
    1. 12.1 Introduction
    2. 12.2 Student Learning Objectives
    3. 12.3 High-Level Design Requirement
    4. 12.4 Setup
    5. 12.5 String Sizing
      1. 12.5.1 Resources for Weather Data for the Installation Site
      2. 12.5.2 Checking for Maximum System Voltage
      3. 12.5.3 Checking for Maximum Operating Temperature of Inverter
      4. 12.5.4 Checking for Minimum Start Voltage
    6. 12.6 Monitoring
    7. 12.8 Modifying the Mechanical Subsystem
    8. 12.9 Attic Penetration
    9. 12.10 Installing Balance of System
    10. 12.11 Lightning and Surge Protection
    11. 12.12 Installing the TED Monitoring System
      1. 12.12.1 Preparing the Main Service Panel
      2. 12.12.2 Installing the MTU and Current Transformers
      3. 12.12.3 Installing the Gateway
      4. 12.12.4 Remote Display
      5. 12.12.5 Footprints Software Setup
    12. 12.13 Certification Testing
    13. 12.14 Troubleshooting
  18. Appendix I: Small Mock Roofs
  19. Appendix II: Roll-Around Walls
  20. Appendix III: 21 ft. by 18 ft. Roof
    1. AIII.1 Introduction
    2. AIII.2 Overall Description of Roof
    3. AIII.3 Sill Details
    4. AIII.4 Wheels
    5. AIII.5 Roof Details
    6. AIII.6 Semipermanent Installation
    7. AIII.7 Live and Dead Loads
    8. AIII.8 Wind Load Calculations