Edinburgh Napier University

  The concept of a high-concentration optical system is introduced detailing the various design types and focusing only on those aimed at photovoltaic (PV) applications. This will include point focus, line focus, imaging, nonimaging, and the classical cassegrain set-up. The theory of high-concentration optics is explained in terms of idealised concepts and maximum limits for each concentrator type and combination. The optical system is broken down into the different stages and materials possible in a high-concentration configuration. The physics of reflective and refractive optics are described, and their associated errors, advantages and a brief overview of past milestones, and recent research trends in the area of high-concentration PVs are presented. Current primary and secondary optics are geometrically explained covering Fresnel, parabolic, heliostat, compound parabolic, hyperboloid, v-trough, and dome-shaped optics. This chapter also covers examples of new secondary optics, such as the three-dimensional crossed-compound parabolic concentrator and the square elliptical hyperboloid concentrator. The aim of this chapter is to provide the basic optical behaviour of high-concentration designs aimed at PV applications considering their geometry, materials, and reliability.