A comprehensive mathematical approach and optimization principle for solar flux distribution and optical efficiency in a solar tower

While designing and optimizing a concentrating solar central tower, it is crucial to obtain the accurate solar flux distribution and optical efficiency for a given heliostat field. Here we present a new model describing solar flux distribution on the surface of an external receiver, based on ray-tracing and a convolution algorithm. The receiver is located at the top of a center tower surrounded by abundant heliostats. The Ray-tracing algorithm allows to predict whether the incident ray is obstructed by adjacent mirrors or not, and the convolution algorithm yields the solar flux distribution on the reflected beams. The performance of single and multi-mirrors are compared with experimental data. Results show that the optical efficiency and solar flux distribution are mainly controlled by the interception factor, and shading and blocking factor. A comprehensive optimization principle is proposed to optimize the optical efficiency of heliostats field. Accordingly, application of this principle increases the average optical efficiency by + 2% during daytime, while decreases the ratio of maximum solar flux to the minimum one from 8.6 to 7.8.

Automated summary

The research models the solar flux distribution on the surface of a central tower for concentrating solar tower systems, and compares the performance of single and multiple mirrors to determine the factors affecting optical efficiency. A comprehensive optimization principle is proposed to optimize the optical efficiency of the heliostat field, resulting in an average increase of +2% in optical efficiency and a decrease in the ratio of maximum solar flux to minimum solar flux from 8.6 to 7.8.