1st Edition

Photovoltaic Laboratory Safety, Code-Compliance, and Commercial Off-the-Shelf Equipment

By Peter T. Parrish Copyright 2016
    390 Pages 165 B/W Illustrations
    by CRC Press

    392 Pages
    by CRC Press

    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.




    How to Use This Textbook

    The Author



    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)



    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


    Safety Posters



    Trade Math for PV—Measurements, Units, and Calculations


    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


    Measurements of DC and AC Electrical Circuits


    DC Electrical Circuits

    AC Electrical Circuits

    Student Learning Objectives


    The Calculator

    Electrical Components

    Measurement Instruments

    Other Equipment

    The DC Electrical Circuit—An Abstraction

    Basic Electrical Concepts—Analogy with Water Flow



    Current Continuity



    Additional Circuit Concepts—Power, Energy, Time, Frequency



    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


    The Site Survey


    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


    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


    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



    Racking Systems—General Considerations


    Student Learning Objectives


    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


    Appendix: Racking Systems on Asphalt Composition Shingle Roofs


    Student Learning Objectives

    Components Comprising the Racking System for Composition Shingle Roofs


    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


    Student Learning Objectives

    Components Comprising the Racking System for a Flat Concrete Tile Roof


    Tools Needed for This Lab

    Student Exercises

    Locating the Rafters

    The PV Module

    Characterization of a PV Module


    Student Learning Objectives


    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



    Student Exercises

    The Measurements

    Other Minor Dependencies

    Modeling the PV Cell, Module, and Array


    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


    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


    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


    Off-Grid PV System with DC-Only Loads


    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


    The Pick List

    Hanging System Components

    Documenting the Final System

    System Certification


    System Documentation

    System Schematic

    System Layout

    System Certification Sheet

    Photograph of Integrated System


    Off-Grid PV System with DC and AC Loads


    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


    Hanging System Components

    Documenting the Final System

    Electrical Schematic

    Physical Layout

    Certification Measurements


    Owner’s Manual

    2.4 kW DC Grid-Tied PV System with Microinverters


    Student Learning Objectives


    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


    Post-Start-up LED Indications


    2.4 kW DC Grid-Tied PV System with String Inverter


    Student Learning Objectives

    High-Level Design Requirement


    String Sizing

    Resources for Weather Data for the Installation Site

    Checking for Maximum System Voltage


    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


    Appendix I: Small Mock Roofs

    Appendix II: Roll-Around Walls

    Appendix III: 21 ft. by 18 ft. Roof


    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