Parabolic Trough Solar Technology

Abstract

Parabolic trough (solar) collectors (PTCs) are technical devices to collect the energy in the form of solar radiation and convert it typically into thermal energy at temperature ranges of 150-500°C at industrial scale. The cylindrical trough shape of the reflecting surface with parabolic section of the mirror shape has the ability to concentrate the incident sunlight onto an absorber tube in the focal line of the collectors. Typical width of such PTC is 0.5-10 m, and the typical concentration factor is in the range of 50-100. The main use of PTC is in solar power generation, but also for process heat in industry. In large-scale concentrating solar power applications, the PTC is the most successful type of concentrating collector design. The first troughs are reported at the end of the nineteenth and beginning of the twentieth century for industrial-scale steam generation. The wide expansion of coal, oil, and gas for heat and power generation left solar energy technology behind until oil price shocks initiated a development step in the 1980s, leading to the successful commercial start of the parabolic trough solar power plants SEGS I-IX in California until 1990. Larger scale capacities have been installed in Spain since 2007, and from there and since then they are spreading out worldwide, in particular in USA, North Africa and Middle East, South Africa and China. PTCs are the main technology for large-scale concentrating solar power (CSP) solar fields. The increasing application in CSP is due to the high conversion efficiency in combination with a standardized modular design with relevant economic advantages over other CSP variants.