Experimental qualification of a novel fixed-focus parabolic trough collector designed for molten salt

Kurzfassung

A parabolic trough collector (PTC) consists of parabolic mirrors that concentrate direct solar radiation onto an absorber tube, in which a heat transfer medium is heated. A typical PTC is a single-axis moving optical system on its concentrator support structure carrying both the parabolic reflectors and the absorber supports. This whole structure is rotated and connected via several pylons. This causes interruptions in the collector row of the plant which is sensitive to failures. Rotation movement and thermal expansion of the receiver tube are absorbed by flexible pipe connectors. These connectors enable the connection between the receiver tube and the fixed pipeline, and are sensitive for frequently reported failures. In this article, an innovative PTC design is presented with the fixed focus principle to eliminate flexible pipe connectors and allow a continuous row of the collectors. The study includes the construction and qualification of a prototype of such a fixed focus PTC, the so-called MS-Trough collector. The mechanical qualification show high rigidity of the collector compared to the state-of-art PTCs. A collector optical efficiency of 74 % and average intercept factor of as high as 86 % are reached. The maximum intercept factor of 94 % is reached on a single collector module. The first erection of the prototype collector gives valuable experience of the MS-Trough collector construction.