SPLTRAK Abstract Submission
Terrain Aware Backtracking via Forward Ray Tracing
Kurt Rhee
Nevados Engineering, San Francisco, CA, United States

Horizontal single axis trackers, which are often used in utility scale photovoltaic power plants, can increase the amount of light captured per module compared to a fixed tilt array and can likewise improve said project’s economic return.  Two factors that may decrease the overall positive effect of horizontal single axis trackers are the amount of grading required to install a standard single axis tracking system and deficiencies in the tracker rotation strategy used to control how the trackers follow the sun.  

Nevados single axis trackers are designed specifically to reduce or eliminate the grading requirement by introducing specialized posts and bearings which can handle post to post net angle changes of up to 15 degrees.  Within a single tracker there may be some number of bays, each with its own distinct normal vector pointing outward from their respective module faces.  This design, which improves the grading aspect of project economics, by definition also makes the tracker system more vulnerable to cross axis and intra-tracker axis slopes. This vulnerability is solved by introducing a new backtracking algorithm based on forward ray tracing algorithm.