Book excerpt: Photovoltaic system design is both an art and a science. Good design requires the integration of many different forms of knowledge, including physics, aesthetics, business acumen, engineering, and architecture. It also requires a systems approach that combines and assimilates different technologies and structures. Good design is accomplished when art meets science to achieve higher-performance and more-efficient and effective systems. Introduction to Photovoltaic System Design provides readers with the knowledge they need to design high-performance PV systems. The text takes a systematic approach to designing PV, with emphasis on custom-design approaches for every system. Readers will encounter the latest, real-world information regarding site evaluations, strings and wire sizing, designing to code, PV components, and monitoring and testing. About the Series: The Photovoltaics (PV) industry stands on the brink of a revolution. The appeal of a new and growing industry has brought an influx of new PV professionals to the market, but the availability of educational resources has not kept pace with market demands. This gap has led to serious quality and performance issues that the industry will need to face in the decades ahead. The Art and Science of Photovoltaics series was developed to fill this education gap. Each book in the series goes beyond simple systematic processes by tackling performance challenges using a systems perspective. Readers do not learn PV design and installation steps in a vacuum; instead they gain the knowledge and expertise to understand interrelationships and discover new ways to improve their own systems and positively contribute to the industry.