Computationally Fast Analytical Ray-Tracer for Central Receiver Systems

An accurate and computationally fast ray-tracer is the key part for the simulation and optimization of the optical irradiation of a heliostat field layout in a solar central receiver system. Within this work we present an analytical ray-tracer which is fast in runtime while obtaining highly accurate results. The runtime improvement is achieved by a faster integration method that does not require a discretization of the receiver. This allows for discretizing the heliostat surface into smaller cells each having a representative flux function to better account for a variety of optical errors. Our new ray-tracer is implemented on the same C++ platform as other existing ray-tracers, such that reasonable cross validation with direct run-time comparisons are possible. Within a case study we demonstrate that the new convolution method decreases the run-time by a factor of 20 compared to HELCal, and a factor of three compared a bidirectional Monte-Carlo ray-tracer, while achieving a stable accuracy of 99.98 %.