Heliostat Characterization at the Central Receiver Test Facility

The Central Receiver Test Facility (CRTF) operated for the Department of Energy by Sandia Laboratories in Albuquerque, N. M. was constructed for the purpose of evaluating solar central receiver design concepts. At this facility working experience with the CRTF heliostat field has been gained and an extensive heliostat evaluation capability has evolved. Valuable information has been gained at the CRTF that will help in the future design and specification of heliostats. This paper summarizes the work that led to the current state of heliostat evaluation capability and includes; a description of the CRTF heliostat, measurements of environmental degradation of mirror reflectance, heliostat beam measurements with an instrumented sweeping bar, beam quality and tracking accuracy data obtained with the newly developed Beam Characterization System (BCS) and comparisons of measured beam data with the heliostat computer model HELIOS.