1st Edition
Photovoltaic Laboratory Safety, Code-Compliance, and Commercial Off-the-Shelf Equipment
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.
Preface
Acknowledgments
Introduction
How to Use This Textbook
The Author
Safety
Introduction
Student Learning Objectives
Working in Extreme Weather Conditions
The Hot, Dry Climate
The Cold Climate
Understanding Heat Stress
Heat Exhaustion—Symptoms and Appropriate Responses
Heat Stroke—Symptoms and Appropriate Responses
Dehydration—Symptoms and Appropriate Responses
Hypothermia—Symptoms and Appropriate Responses
Frostbite—Symptoms and Appropriate Responses
Preventing Heat or Cold Stress
General Safety Training
Personal Protective Equipment (PPE)
Eye Protection and Gloves
Protective Helmets (a/k/a Hard Hats)
Aprons
Footwear
Working at Heights
Safety Barriers
Guardrail Systems
Safety Netting
Personal Fall Arrest: Body Harnesses
Rescue Plan
Ladders and Ladder Safety
Electrical Safety
Overhead Power Lines
Operating Electrical Equipment
Moving and Carrying Heavy Objects
Roofs and Attics
Lockout/Tagout
Safety Posters
Notes
References
Trade Math for PV—Measurements, Units, and Calculations
Introduction
Student Learning Objectives
The Decimal System of Notation
Scientific Notation (Exponential Notation [Base 10])
Adding, Subtracting, Multiplying, and Dividing in SN
Multiplication and Division
Addition and Subtraction
Metric System and Prefixes
Nonstandard Units of Measure
Rational Fractions, Decimal Fractions, Ratios, and Percentages
A–B Comparison
Change of a Value (over Time)
Student Exercises
A–B Comparison
Significant Digits and Precision
Conversion from Metric Units to Imperial (English) Units and Back
Basic Algebra
Ohm’s Law
Watt’s Law
Order of Operations
Trigonometry of Right Triangles
The Right Triangle
The Pythagorean Theorem
Calculations Involving the Pythagorean Theorem
The Three Trigonometric Functions
Evaluating the Angle θ and Inverse Trigonometric Functions
Reciprocal Trigonometric Functions
Length, Area, and Volume
The Celestial Sphere
Analyzing Word Problems
Mastering the Use of a Calculator
Addition and Subtraction
Multiplication and Division
Trigonometry
Measurements of DC and AC Electrical Circuits
Introduction
DC Electrical Circuits
AC Electrical Circuits
Student Learning Objectives
Setup
The Calculator
Electrical Components
Measurement Instruments
Other Equipment
The DC Electrical Circuit—An Abstraction
Basic Electrical Concepts—Analogy with Water Flow
Charge
Current
Current Continuity
Voltage
Resistance
Additional Circuit Concepts—Power, Energy, Time, Frequency
Power
Energy
Time and Frequency
Summary of Circuit Concepts
Nominal Specifications
DMM Measurement Accuracy
Absolute Calibration of Measurement Instruments—Standards
Student Exercises
Measuring the Voltage Standard
Color Coding for Resistors
Measuring Resistance with the DMM
Measuring DC Voltage with the DMM
Single Batteries
Multiple Batteries—In Series and in Parallel
Bench Power Supply
Powering a 12 V LED
Powering a 10 Ω, 50 W Resistor
AC Circuit Theory
What Is a Sinusoidal Signal?
Electrical Utility Service
Measuring a 120/240 VAC 200 A Split-Phase Service Panel
120 VAC Branch Circuit (L1 or L2)
240 VAC Branch Circuit (L1 and L2)
Measuring Current in a 120 VAC Branch Circuit
Measuring the Voltage, Current, Power, and Energy of a 120 VAC Outlet
Notes
The Site Survey
Introduction
Student Learning Objectives
Organization of This Lab
Prior Activities
Preliminary Technical Sales Proposal
Sample Module Rows
Determination of All Authorities Having Jurisdiction (AHJs)
The Virtual Site Survey
Resources
Example of a Site Survey
County Assessor’s Map
Sketch of the Property Including House
Documentation of Roof Sections
Site Survey Document
Student Exercises
Student Site Survey
Rafter/Truss and Attic Details
Main Service Panel
Use of a Subpanel
Locations for Other Major Components
Grounding of Electrical Service
Trenching
Shading Analysis
Performing a Manual Shading Analysis Using the SolarPathfiner
Performing an Advanced Shading Analysis Using the SolarPathfiner
Performing a Shading Analysis Using the Solmetric SunEye
Summary
Notes
Racking Systems—General Considerations
Introduction
Student Learning Objectives
Setup
Portrait Versus Landscape Layouts
Positioning the Rails and Brackets
The 25% and 75% Rule
Maximum Bracket Spacing
Standard Residential Rafter/Truss Spacing
Constraints on Portrait Orientation
Constraints on Landscape Orientation
Case Study: The 60-Cell, 156 mm Square Cell PV Module
Design of Layout for a Single PV Module
Small Mock Roof Details
Locating the Rafters
Pull-Out Strength of Lag Bolts
Wind Forces on Roofs
The "Simple" Approach
Student Exercises
Model Structures
Calculations Based on Complicated Approach
Roof-Specific Installation of Brackets
Notes
Appendix: Racking Systems on Asphalt Composition Shingle Roofs
Introduction
Student Learning Objectives
Components Comprising the Racking System for Composition Shingle Roofs
Setup
Tools Needed for This Lab
Student Exercises
Design Layout for a Single PV Module
Locating the Rafters
Begin Layout
Installing the Brackets
Choice of Post
Installing Flashing
Dimensioning and Attaching the Rail
Installing the PV Module
Appendix: Racking Systems on Flat Concrete Tile Roofs
Introduction
Student Learning Objectives
Components Comprising the Racking System for a Flat Concrete Tile Roof
Setup
Tools Needed for This Lab
Student Exercises
Locating the Rafters
The PV Module
Characterization of a PV Module
Introduction
Student Learning Objectives
Setup
The TiltAll Tripod
Choice of PV Module—The Renogy RNG-100D
Components and Instruments
The Gnomon
Digital Multimeter (DMM)
Bead Wire Thermocouple and Black Electrician’s Tape
Clamp-on Ammeter
Digital Infrared Thermometer
Irradiance Meter
Tilt Meter
Torpedo Level
Thermometer
Calculator
Student Exercises
The Measurements
Other Minor Dependencies
Modeling the PV Cell, Module, and Array
Preface
The Standard Methodology
Universal Constants: Cell Voltage and Cell Current Density
Partial Shading of PV Modules and Bypass Diodes
Overcurrent Protection in Three or More Strings
High-Performance PV Modules
Unity in the Data?
How Many Cells in a Module?
Commercial PV Module Electrical Characteristics
Goals for This Laboratory
Introduction
Student Learning Objectives
Simple Component Models in PSpice
The Resistor Revisited
The Voltage Source
The Current Source
The Diode
Plotting the Diode I-V Characteristic
Two-Element Model for the PV Cell
I-V Characteristic for the PV Cell
Separately Displaying the Source, Diode, and External Load Currents
The Concept of Load Resistance
Maximum Power Point (MPP)
Cell Efficiency
I-V and P-V Characteristics for Different Irradiance Values
Equivalent Circuit for PV Cell Including Parasitic Resistances
Temperature Dependence of PV Cell Characteristics—Voc
Temperature Dependence of PV Cell Characteristics—Isc
Student Exercises
The PSpice Simulation Program
The Spice Netlist
Creating the Netlist Using MS Notepad
Using MS Excel to Record and Plot Data
Using the Power of PSpice
Using the Voltage Source in Place of the Load Resistor
The New Netlist
Simulating a PV Module Composed of 36 Each of 6 in. Cells—The Renogy RNG-100D
Adding the Parasitic Resistances
Library Element "cell_1.lib"
The Effects of Shading at the Cell Level
Optional Exercises
Lead-Acid Absorbent Glass Mat Batteries
Introduction
Student Learning Objectives
Overview of Lead-Acid Batteries
Markets for Pb-Acid Batteries
The Automotive Market
Conventional Traction Market
Energy Storage Market
Lead Alloys
Comparison with Other Battery Technologies
Characterizing the Pb-Acid Battery
Nominal Battery Voltages
Battery Capacity
State of Charge and Depth of Discharge
More on Battery Capacity
Expected Life Cycles
Three-Stage Charging
Student Exercises
Charging the PVX-840T
Discharging the PVX-840T
Notes
Off-Grid PV System with DC-Only Loads
Introduction
Student Learning Objectives
Overall Design Philosophy
The Load Profile
Days of Autonomy and Battery Energy Capacity
Measuring the Depth of Discharge
PV System Rating
System Calculations—The Role of Energy Conversion Efficiency
Charge Controller Efficiency
Charging/Discharging Efficiency of AGM Battery
Depth of Discharge and Life Cycles
Student Exercises
Load Profile Calculation
Days of Autonomy
Total Energy Requirement
Charging/Discharging Efficiency of AGM Battery
Charging Efficiency of Charge Controller
Required Energy Storage in Battery
Required Energy Delivery by PV System
PV Subsystem Simulation
Document Final System Configuration
Balance of System Components and Conductor Sizing
Battery Current
PV Circuit Conductors
Electrical Schematic and System Layout
Layout
The Pick List
Hanging System Components
Documenting the Final System
System Certification
Photographs
System Documentation
System Schematic
System Layout
System Certification Sheet
Photograph of Integrated System
Note
Off-Grid PV System with DC and AC Loads
Introduction
Student Learning Objectives
Overall Design Philosophy
AC Loads
DC Loads
DC-to-DC Converters
The Load Profile
PV System Sizing
Days of Autonomy
Number of Battery Cycles
System Calculations
Student Exercises
Load Profile Calculations
Days of Autonomy
Total Energy Requirement
Sizing the Battery Subsystem
Sizing the PV Module and Charge Controller
PV Subsystem Simulation
Document the Final System Configuration
Electrical Schematic and System Layout
Layout
Hanging System Components
Documenting the Final System
Electrical Schematic
Physical Layout
Certification Measurements
Photographs
Owner’s Manual
2.4 kW DC Grid-Tied PV System with Microinverters
Introduction
Student Learning Objectives
Setup
The Roof
Racking Equipment
Choice of PV Module
Choice of Microinverter
Simulation of PV Performance and Monitoring
Personal Protective Equipment
Materials and Tools
High-Level Design
Estimated Consumption Based on Electricity Bill History
Estimated Consumption Based on Square Footage of Living Space
Estimated Consumption Based on Load Profile
Site Assessment
Perform Shading Analysis
Final PV Module Layout
Roof Loading Calculations
Mechanical Loading—The Live and Dead Loads
Live Loads
Dead Loads—PV System and Roof
Dead Load of the Roof Material
The Total Dead Load
Calculation of Maximum Horizontal Span of a Roof Rafter
Wind Loading
Design Wind Pressure for the Site
The SolarMount Code-Compliant Installation Manual 227.3
Basic Equation for Design Wind Loading for Components and Cladding
Total Design Load (Downforce and Uplift)
Calculating Uplift Force on Each Standoff and Comparing to Pullout Strength of Fasteners
The Concept of Design (Safety) Margin
Fire Marshal Setbacks
Layout of PV System
Single-Line and Four-Line Diagrams
A Single-Line Diagram
A Four-Line Diagram
National Electrical Manufacturers Association
Underwriters Laboratory
The Difference between Four-Line and Single-Line Diagrams
Installing Mechanical Subsystems—Standoffs, Flashing, and Rails
Sketch of Layout in Notebook
Transfer Sketch to Roof
Attach Standoffs, Flashing, Rails, and AC Cable
Documenting the Mechanical Subsystem—Standoffs, Flashing, and Rails Inputs from Roof Details—Optional
Installing PV Modules, WEEB Grounding Clips, Microinverters, and AC Cabling
The First Row
The Installation Map Monitoring System
Installing Balance of System
Lightning and Surge Protection
Installing the Enphase Monitoring System
Connecting the Gateway to Enphase Internet Site
Energizing the System
Activating the System
Certification Testing
Troubleshooting
Post-Start-up LED Indications
Notes
2.4 kW DC Grid-Tied PV System with String Inverter
Introduction
Student Learning Objectives
High-Level Design Requirement
Setup
String Sizing
Resources for Weather Data for the Installation Site
Checking for Maximum System Voltage
Monitoring
Four-Line and Single-Line Diagrams for the String Inverter System
Modifying the Mechanical Subsystem
Attic Penetration
Installing Balance of System
Lightning and Surge Protection
Installing the TED Monitoring System
Preparing the Main Service Panel
Installing the MTU and Current Transformers
Installing the Gateway
Remote Display
Footprints Software Setup
Certification Testing
Troubleshooting
Appendix I: Small Mock Roofs
Appendix II: Roll-Around Walls
Appendix III: 21 ft. by 18 ft. Roof
Biography
Peter T. Parrish is an adjunct professor at Santa Monica College, California. He also teaches at Cerritos College, Norwalk, California, and Irvine Valley College, Irvine, California. In addition, he has taught at Pierce College, Woodland Hill, California; College of the Desert, Palm Springs, California; and College of the Canyons, Santa Clarita, California, where he developed the solar program and chaired the Alternative Energy and Transportation Technology Department. He has taught and conducted research at the University of Massachusetts, Amherst; served as a consultant to MIT Lincoln Laboratories, Lexington, Massachusetts; and held adjunct faculty positions at Northeastern University, Boston, and Drexel University, Philadelphia. He received his BS from the University of Colorado and his Ph.D from the University of California, Berkeley, both in physics.
"This book helps fill a shortage in modern support material for technical education and training for the rapidly growing photovoltaics systems industry. It is particularly appropriate for the very active US market, since aspects such as regulation and roof structure are regionally specific and some units of measurement in the book are used only in the US and a few other locations, but there is much here to learn for trainee technical staff all over the world. The style is appropriately informal and anecdotal for the technical education levels at which it is directed. The pedagogical concern and experience of the author is evident, for example, in a focus on understanding the principles through simpler tools than the excellent SunEye, for shading analysis."
—Richard Corkish, School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, Australia"The approach [of this book] is good. Making sure the students know enough math and electrical theory is essential if they are to understand the subsequent material. The emphasis on safety is very important and putting it up front makes that point. I like the fact that the book provides material for other important photovoltaic (PV) activity, since if a system is not sold, then it will not be installed."
—Roger Messenger, Florida Atlantic University, Boca Raton, Florida, USA"The material is written in easy-to-understand layman’s terms while focusing on multiple career areas. I believe this allows instructors the ability to draw from the material what they need in order to provide effective training for the specific career(s) that they may be instructing students for. The materials are written in a simplistic format that should allow students to easily follow the materials while working on the labs. I believe that having the sections on safety and related mathematics is integral to producing successful students. Many of the texts that I have reviewed/used do not have these components and present materials with the assumption that either instructors will automatically cover these materials or that students come to the class with this knowledge already in place. … [This is] a very well-written book that can be integrated into most solar PV training applications. It covers concepts in a well-thought-out manner that follows a logical progression that builds on basics and works upward from there. This logical progression should allow students to easily and successfully progress through the concepts being presented."
—Daniel M. Sherry, Alamo Colleges, St. Philip’s College, San Antonio, Texas, USA"Overall, this is a good book on the laboratory component of photovoltaics. It contains safety, handling, and measurement procedures for photovoltaic (PV) experiments. ... The exercises and PV content are good and well described. Several simulation programs are included."
—Tapas Kumar Mallick, Environment and Sustainability Institute, University of Exeter, Penryn Campus, UK"This book is interesting and useful, as it covers aspects of solar cells work that is not usually covered in other textbooks. The information provided is very practical and would be useful for a wide range of personnel involved in solar cells installation and design."
—Yeng Ming Lam, Nanyang Technological University, Singapore"This is a practical book on understanding and installing photovoltaic (PV) systems for residential applications. It clearly explains how to install rooftop PV systems, and provides a well-balanced blend of practice and theory with explanations on how a PV cell works, how the system operates, cell physics, and the details of mechanical and electrical integration…Anyone interested in learning about the practical aspects of PV arrays, and what is needed to install them, will be able to make use of this book to help guide them on proper installation and making good choices when designing a PV system. Others who may also find this book useful include system designers, marketing and sales people, and even those involved in issuing permits for PV systems."
—John Shea, IEEE Electrical Insulation Magazine, May/June 2017 Issue