Photovoltaic Design & Installation For Dummies®
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Library of Congress Control Number: 2019932064
ISBN 978-1-119-54435-7 (pbk); ISBN 978-1-119-54433-3 (ebk); ISBN 978-1-119-54437-1 (ebk)
Solar electricity is one of the most accessible forms of renewable energy available, and it can be adapted to fit anyone’s specific needs. The source of it, sunlight, allows photovoltaic (PV) modules to produce electricity and perform useful work, such as running electrical loads or putting energy back into the utility grid.
Globally, there has been an incredible increase in demand for solar modules and PV systems since the turn of the 21st century. No longer is PV technology limited to NASA spacecraft and backwoods cabins. Nowadays, PV systems are within reach for many people. This global demand and increased accessibility and affordability have helped transform the PV industry from a small cottage industry into a worldwide megabusiness.
As a renewable energy educator, advocate, and user, my primary goal is to see the solar industry grow successfully and sustainably — two things that require consistent high-level performance from the people “in the trenches” or, more appropriately, “on the roofs.” PV system designers and installers are tasked with providing high-quality systems that can benefit clients for more than 20 years. If you follow the information, advice, and tips I present in this book, you’ll be well on your way to completing this task with the best of them. (Of course, no perfect power source is out there. To be a good PV system designer and installer, you have to realize the limitations of PV systems, which is why I help you consider those limitations in this book, too.)
As the PV industry expands and captures the attention of more and more individuals, so does the amount of information about these systems. Photovoltaic Design & Installation For Dummies adds to this ever-expanding mass of information, but it stands out in its ability to provide you with practical, hands-on specifics. My intention with this book is twofold: to give you the ability to jump headfirst into the PV industry and to arm you with the knowledge you need to competently install a system (more or less) on your own. I use my real-world experience and desire to see every roof holding a well-designed and properly installed PV system to help you.
My approach is to give you the information you need in easy-to-understand sections that are relevant to the work you’ll be expected to perform as a PV designer and installer. (I don’t expect you to read this book from cover to cover, but if you do, I’ll take it.)
Note: This book is focused on the applications used to power homes and small businesses — with or without the electrical utility present — but you can take the principles and guidelines I present and adapt them for just about any application you need.
Even though the title of this book has the word photovoltaic in it, most folks in the industry don’t throw that word around day in and day out. Instead, we prefer to say PV — it’s simpler, and it creates far fewer tied-up tongues.
Also, throughout this book you’ll see references to PV array and PV system. The former term refers to the collection of PV modules that makes up the PV array, and the latter term refers to the PV array and all the associated components (disconnects, inverters, batteries, and so on) that make it operational and useful.
In addition, all time references throughout this book are based off solar time (which I cover in Chapter 4). Solar noon is the time of day exactly between sunrise and sunset, when the sun is at its highest point in the sky that day. Your longitude, the time of year, and whether you’re subjected to daylight saving time influence the relationship between your clock and solar time.
Last but not least, the following conventions help you more easily sort through all the new ideas I throw at you:
monofont. (Note that when this book was printed, some Web addresses may have needed to break across two lines of text. There’s no extra punctuation, though, so just type in exactly what you see, pretending as though the line break doesn’t exist.)So many interesting side notes about PV technology, politics, and installation techniques exist that I could easily use all the pages of this book for nothing but various tangents. I think I’ve done a good job of sticking to the main points to give you the most important information you need, but some stories and bits of knowledge are just too good to keep to myself. These stories and tidbits are included in the gray-shaded boxes (sidebars) and paragraphs marked with the Technical Stuff icon. Don’t feel bad for skipping over this text if that’s what you choose to do; you aren’t going to miss out on the essential information a PV system designer and installer needs to know.
Simply by picking this book up, you’ve already proven my first assumption, that you have an interest in finding out more about PV systems, to be true. I also make some other assumptions about you; here they are, for your viewing pleasure:
Photovoltaic Design & Installation For Dummies is arranged in five different parts. Each part can stand alone or be read in conjunction with the others. If one of the following parts (or a particular chapter within that part) excites you more than the others, by all means, head there first.
Get ready to discover the fundamentals of PV design and installation in this part. Here, I introduce you to the major components used in the systems you’ll most likely be working with. And in case you need a refresher course on (or an introduction to) the fundamental electrical principles, this part has you covered. It also explains the specific relationship between the sun and the earth and how this relationship affects where you should position a PV installation.
Everything you ever wanted to know about the major components of PV systems can be found in Part 2. If you’ve been wondering how a PV module works and how the acid inside a battery can make electricity, here’s your chance to find out those things. This part also covers the basic functions of the other major components of PV systems: charge controllers, inverters, and wiring. And because safety should always be your top priority, I also get you acquainted with essential safety devices (think fuses and circuit breakers).
In this part, I walk you through the different methods for sizing your PV systems (figuring out how many PV modules you need), whether they’re grid-direct or battery-based, and the necessary wiring and safety devices. Sizing is the area that can make or break your system. If you properly size and specify (select) all the system components, your system will likely pass inspection much faster, and your client will be left with a safe, efficient way of capturing and using solar energy. If, however, you make major errors in your preparation and design, fixing those errors after the system is already installed can be a difficult (and sometimes dangerous) task.
Part 4 is where I cover the physical installation process, as well as the activities that precede and follow it. I kick things off by walking you through the permitting process so you have the permission you need to install the system. Next, I cover the safety considerations you need to have in mind when you’re out installing systems. (After all, PV construction sites offer a number of hazards for everyone on-site; by preparing for these hazards, you can avoid them altogether.) After that, I break the installation process into the mechanical and electrical portions. Then I give you a process to follow when you’re ready to commission (turn on) the system and get the modules working prior to the mandatory building department inspection. Finally, I address proper PV system maintenance.
The Part of Tens is designed to give you small chunks of information for a quick and easy read. Prepare to find out some of the common mistakes made in PV installations so you can do your best to avoid them, as well as some quick tips on how to keep the PV systems you design and install working as well as they should.
Throughout this book, I use the following icons to bring your attention to interesting, important, or even downright critical information.
Although I’d love it if you remembered everything in this book, I know that’s practically impossible. That’s why I mark ideas I want you to keep in mind no matter what with this icon.
Every now and then I tend to “nerd out” on you with interesting but nonessential information. I promise to keep these asides (relatively) short and to warn you that they’re coming with this icon.
This little bull’s-eye brings your attention to information that may make your job a little easier.
Don’t let anyone fool you. PV systems pose real dangers. This icon alerts you to a situation that requires special attention and caution.
Wondering where to start reading? If it were me, I’d jump to Chapter 6; this is where I get into the PV modules themselves — far and away the most interesting part of PV systems (in my humble opinion). If you’d rather choose the approach my children take — which is to decide what you think is best despite my advice — flip to the table of contents. There you can breeze through all the chapters and see what jumps out at you.
After you get what you want out of this book, I strongly suggest you find a way to put that knowledge into action. Numerous organizations that provide hands-on training and experience are available, and these classes are an excellent way to get your hands on some equipment and have access to individuals who are knowledgeable and eager to help you master PV systems. Then, if you have the means, install a PV system on your own home. Doing so lets you run the show and gives you some personal insight into what it takes to install PV systems (plus it provides you with a slightly less stressful situation for your first solo installation because you don’t have a client or supervisor looking over your shoulder).
Wherever you end up going first in this book, realize that you’re jumping into an exciting and rapidly evolving technology and industry. No matter where you go within the pages of Photovoltaic Design & Installation For Dummies, you’ll be well on your way to becoming involved with one of the most dynamic and exciting industries you can imagine.
Part 1
IN THIS PART …
Understanding the fundamentals of photovoltaic (PV) systems is the key to designing and installing high-quality systems that’ll perform beyond your (and your clients’) expectations. That’s why this part provides the foundation you need to move forward with designing and installing PV systems.
Chapter 1 gives you an understanding of where PV systems started, where they are now, and where they’re headed; Chapter 2 gives you a feel for the major components used in all types of PV systems and how they relate to each other. Chapter 3 provides an overview of the electrical fundamentals that drive system designs and installations, and Chapter 4 outlines the relationship between the sun and the earth and guides you on assessing the solar resource. Rounding out the bunch, Chapter 5 walks you through the process of selecting where on a client’s property to install a PV system; it also helps you quantify the solar resource at a particular location.