Linear Fresnel collector demonstration on the PSA, Part I – Design, construction and quality control

Linear Fresnel collectors have the potential to reduce levelized electricity costs (LEC) of solar thermal power plants and thus accelerate sustainable market penetration of solar thermal power plants. It is expected that linear Fresnel collectors will be cheaper than conventional parabolic trough collectors. On the other hand the efficiency of this new collector concept will be lower than that of parabolic troughs. So far no reliable information is available whether the reduced investment in combination with the reduced efficiency causes a final reduction of the LEC. To overcome this lack of information a German consortium was formed and led by MAN-Ferrostaal Power Industries with the Solar Power Group (SPG) aiming at the design, construction, operation and assessment of linear Fresnel collectors. Within the German FRESDEMO project a first prototype with a length of 100 m and a width of 21 m was erected at the Plataforma Solar de Almeria (PSA) in Spain. The steel structure of the prototype supports a fixed central absorber tube located in the centre of a secondary reflector and 25 rows of slightly curved primary mirrors. The challenge of designing a cost efficient collector system is to guarantee the required optical and mechanical quality of all subsystems such as primary mirrors, tracking system and secondary reflector at minimised costs. These quality aspects have to be considered not only during design phase but also during construction on site.