Progress in the design and the applications of linear Fresnel reflectors - A critical review

Solar concentrating power is one of the most promising ways of producing clean electricity by utilizing the incident solar irradiation on the earth. Linear Fresnel reflector (LFR) is one of the major concentrating solar systems for producing useful heat in medium and high-temperature levels (< 500 degrees C). The LFR is a low-cost technology which presents sufficient thermal performance and so it is characterized as an interesting and valuable choice for utilizing the solar irradiation. The objective of this work is to summarize the existing designs of LFR and the novel ideas which aim to enhance the LFR performance. These ideas regard the optical and the thermal efficiency increase. Moreover, the LFR is compared with rival technology, the parabolic trough solar collector. The thermal and power applications with the LFR are also studied in this review paper. It is found that the most usual designs regard trapezoidal cavities and evacuated tube receivers. A lot of studies are focused on the optimization of the secondary reflector of the LFR. Moreover, there are interesting ideas about the modification of the primary concentrator in order to increase the optical efficiency. The final conclusions of this work indicate the future trends for this solar system and summarize the existing situation.