Optimization and performance of an optically asymmetrical heliostat field

Abstract
The recent trend of integrating CRS into hybrid plants with combined cycles is creating a new situation, since the solar field is forced to make use of sites near gas pipelines and industrial areas. Land there becomes a significant portion of plant cost and constraints lead to some particular problems for layout optimization and subsequent optical performance. The COLON SOLAR heliostat field represented a real challenge during the design phase, because of the important restrictions stemming from the available site. Field optimization required adapting the existing codes to the COLON SOLAR site, since the field is not oriented to the North, is narrower than required and presents a number of restrictions associated with industrial pipelines and electrical grids (both aerial and buried) found on the site. Flux distributions on the absorber surface obtained with HELIOS and DELSOL3 demonstrated that in any given situation the centroid shifted about 25° to the East because of the higher number of heliostats to the West. The influence of such peculiarities in the field on design and the minimization of their effect on plant perfomance are discussed.