An investigation on a compound cylindrical solar concentrator (CCSC)

A compound cylindrical solar concentrator (CCSC) was presented in this paper. CCSC is comprised of cylindrical Fresnel lenses, parabolic reflectors and secondary reflectors. A single-axis tracking is employed on it. The parabolic reflectors were used for taking the place of two flanks of cylindrical Fresnel lens where have relatively lower optical efficiency and also can widen the aperture area. A simulative investigation was carried out to illustrate the changes of focal width and focal length with tilt incidence. According to the change of focus, the regulations that receiver set in different positions have been analyzed and thus a proper position of receiver has been found to set experimental system. The experimental results showed that the optical efficiency of CCSC is about 82.8–84.1%. The highest temperature is approaching to 250 °C with total solar irradiation about 1050 W m⁻². The effect of tilt incidence was also investigated experimentally. The experimental receiving efficiency is very close the simulation result. It is higher than 90% when tilt angle is within 40° which increases by 20° compare to the condition that receiver is set in the focus of Fresnel lens. Thus, the left position can increase the acceptance angle effectively. However, when tilt angle increases continuously, it declines very quickly. All in all, CCSC can utilize the best solar rays efficiently and provide 200 °C temperature heat easily. It can be used for middle temperature field.