Hi Tamir,
The new version of SAM has an improved algorithm for modeling self-shading for PV arrays with 1-axis tracking. We tried to address some of the issues you raised in your comments.
On the PV Subarrays page, we added two new inputs for each of the four possible subarrays: The
Shading mode for 1x trackers allows you to choose how you want SAM to model shading for one-axis tracking, and the
Ground coverage ratio input (GCR) replaces the two row spacing inputs from previous versions.
The shading mode options are:
Self-shaded models the array with no backtracking, but does estimate losses from self-shading caused by shading of modules in one row by modules in neighboring rows based on the GCR value you specify. This is an improvement over previous versions of SAM that assumed that rows in arrays with one-axis tracking were ideally spaced to have no self shading.
Backtracking adds backtracking to the self-shaded option, and adjusts the tracking angle to minimize shading.
None uses the approach of the previous versions of SAM. Because this option does not account for any self-shading, it tends to overestimate the array's production. We included this option to allow for comparison between the different options to see the effect of the self-shaded and backtracking options, and for comparison between results from this version and older versions of SAM.
The new GCR input only accepts values between 0.01 and 0.99 (0.01 < GCR < 0.99). If you specify a value outside of that range, the Beta version generates a simulation error.
You can run a parametric study on the GCR to see its effect on the array's output (with the self-shaded or backtracking options enabled).
If you have time to take a look at the Beta version, we would really appreciate any comments or suggestions. You can download the Beta version from the
Downloads page
.
Best regards,
Paul.