Near Shading Loss in Version 8 Showing as Zero?

[JStief]

Hello - For the simulation (bifacial, single axis tracker, utility scale, Southwest USA) in question previously in the latest version 7 release I was getting ~2% for "Near Shadings: irradiance loss" in the waterfall due to ShdDLss (diffuse) and ShdALss (albedo). In version 8 I am getting 0% for the exact same variant. Is this an error? The annual energy result is also off by a commensurate amount.

In version 7 I had been using a representative block for the shading scene (far fewer modules than the actual project, no actual topography). In version 8 this created a warning due to the number of modules being so many fewer than the System window indicated, so I created another variant with additional trackers to see if that was the issue. However, I am still getting zero ShdLoss. Backtracking is on, so zero beam shading is expected, but I would expect to see some diffuse and albedo shading.

Screenshot of the version 8 near shading window is attached.

Thank you

[Michele Oliosi]

You should check the following window : 3D scene > Tools > Tracker diffuse shadings definition.
There you can check whether the representative tracker has shading masks (neighbors), if the loss is zero it probably is not identifying masks properly.
You can switch to "all trackers" which is slower but is more accurate and robust. Let us know if that fixes the issue.

[JStief]

The simulation was already being run using the "All trackers" option in the "Trackers diffuse shading definition" selection window. However, the trackers all still appeared blue in color. I changed to "Central tracker" and orange/green shading become visible. I ran the model (still using the central tracker option) and the results were what was expected, extremely close to the version 7 PVsyst result.

 

I cloned the variant, changed the trackers diffuse shading definition back to All. Reran the model, and near shading is back to zero again. For now I can simply use the central tracker option, but wanted to note this unexpected behavior.

[Michele Oliosi]

Okay, this seems to be a new bug. We will take a thorough look into this.

Could you send us your project at support@pvsyst.com? This would be extremely valuable to fix the issue as quickly as possible.