Ensuring performance by geometric quality control and specifications for parabolic trough solar fields

Abstract

Solar field thermal output depends on the optical, geometrical and thermal parameters of the installed solar collectors. In addition to appropriate collector design and quality of the components, proper assembly and installation processes are most relevant for high performance. Target values for the intercept factor are in the range of 96-99% for typical operating conditions. These values can only be reached if appropriate quality specifications are fulfilled. Specification values are suggested and their implications on intercept factors are discussed based on the well-proven statistical calculation model from Bendt and Rabl. A variety of measurement techniques which can be applied for measurement and control of the geometry parameters are discussed. The application of geometric quality control measurement techniques for prototype collector development as well as for series production of large fields has already contributed to relevant performance increase of parabolic trough collector fields and is constantly required to maintain high output quality of solar field design, production, and assembly.