Exergy analysis of solar thermal collectors and processes

This paper presents a review of exergy analysis of solar thermal collectors and processes. It includes not only various types of solar collectors, but also various applications of solar thermal systems. Initially the fundamentals of second law analysis are briefly presented as well as the exergy of solar radiation, which is the input to any solar system. Concentrating and non-concentrating collectors have been analyzed, including parabolic dish and parabolic trough collectors from the first category, and flat-plate collectors, air solar heaters, and evacuated tube collectors from the second category. Hybrid photovoltaic/ thermal collectors have also been examined. Applications and processes include the use of phase change materials either in the collection or storage of thermal energy, drying, heating, multigeneration, trigeneration, solar cooling, solar assisted heat pumps, domestic cogeneration, hydrogen production, hybridization with other renewables, solar ponds, power plants and desalination/distillation. Through literature review on the above subjects it is shown that exergy analysis, which gives a representative performance evaluation, is emphasized as a valuable method to evaluate and compare possible configurations of these systems.