[...] The guiding principle for the writing of this book was the desire to create an educational guide, at the level of tertiary education, which, on the one hand, adequately covers the theoretical and practical background of PV systems technology, and on the other hand, provides the trainee with the necessary tools for professional use or postgraduate studies.

Emphasis was placed, on the one hand, on the conceptual foundation of topics related to solar radiation, the mechanism of PV phenomenon and the operation of PV elements, and on the other hand, on the detailed study of PV systems and the methodological determination of their appropriate size, which is completed with the examination of selected examples of typical PV applications. The structure of the material follows the methodology of approaching the main objective, namely the methodology of calculating a PV system, after studying the phenomena, technology and physical quantities related to the PV phenomenon. The presentation of the topics is done with a critical search for the meaning of concepts, within the framework, of course, of the educational character of the book. Those interested in further analysis and information on the subject will find a wealth of recent references on each topic of special interest, as well as references to established textbooks included in the bibliography.

In general, the PV phenomenon, its interpretation and the factors that affect its appearance are presented in detail. The relevant technology for the production of photovoltaic cells and PV frames is briefly examined. Then, the methodology for calculating the size of a PV system is studied, initially for continuous sunny days and then, with the possibility of certain days of autonomy, by applying the conservation of energy provided by the sun. The relationship of dependence of the provided electrical energy on the PV array is formulated, based on solar potential, operating conditions and the capabilities of the PV frame. Similarly, the determination of the remaining components of a PV system is examined. The study is completed with the presentation of the methodology for calculating PV hybrid systems, after a brief study of wind energy technology. [...] (from the book's preface)