PVC Shade Scene Differences in Losses

[Valerie Chan]

I am working on one project but analyzing two scenarios for it via PVcase. One scenario is utilizing 2&3-string tracker rows and the other is utilizing 3&4-string tracker rows. Both scenarios have the same building limits and topographic layout, but when exporting these PVC's into PVsyst, the losses from these scenarios are much different than anticipated. To troubleshoot, I created 4 PVsyst variants and got these near shading losses: 
1. Unlimited sheds: -2.64%

2. PVC from 2&3-string tracker layout: -0.76%

3. PVC from 3&4-string tracker layout: -2.32%

4. PVC from 2&3-string tracker layout, but manually changing all z coordinates to 0: -2.45%

In trying to troubleshoot with PVcase directly, they could not identify the issue. What are some other troubleshooting suggestions or is there a way to understand where the difference comes from?

Thanks,
Valerie

[Michele Oliosi]

Part or most of the differences may come from the diffuse shadings calculation. With large scenes I would advise to always go through the 3D scene >Tools > Tracker diffuse shadings definition tool.

Here is a help page that should cover this topic: https://www.pvsyst.com/help/tracking_diffuse.htm