Testing of Moonlight Flux Measurement Method Using RP3 Solar-Trough Mirror Heliostat

For large-scale central receivers, authors have proposed a new indirect measurement method of the concentrated solar flux distribution of the heliostat field based on moonlight concentration experiments. The flux density distribution of the sunlight on the receiver surface could be estimated using the moonlight concentration ratio function of the heliostat field and the direct normal solar irradiance. But a natural question are how the sun and moon differ as light sources and what effect these differences have on the distribution of concentration ratio on the target by light concentrating experiments. Thus, a single mirror heliostat with azimuth-elevation drive was installed in the 1MWe DAHAN solar tower power plant in Beijing. The heliostat mirror was a standard outer RP3 solar-trough mirror facet. The heliostat was essentially designed to investigate and compare different sun shapes and moon shapes for accurate solar concentrator optical simulations. Comparisons of experimental and simulation results on the target plane for the sun and the Rill moon show that the two light sources have the similar effects on the concentration ration distribution.