PVsyst's forum

Hi,
We have actual measured GHI data from site and actual tracker gain obtained from it.
When the same GHI data was imported in PVsyst, it showed a higher tracker gain than the measured. We understand that one reason is the diffused content variation between actual & estimated which affects tracker gain. The differences are tabulated below.
Actual at site Pvsyst Prediction for the same GHI
Month GHI (kWh/m2/d) Tilt radiation (kWh/m2/d) Radiation gain on tracker plane (%) Tilt radiation (kWh/m2/d) Radiation gain on tracker plane (%)
Jan 5.23 6.15 17.59% 6.55 25.15%
Feb 5.49 6.46 17.67% 6.79 23.60%
Mar 6.31 7.27 15.21% 7.88 24.84%
Apr 6.19 7.03 13.57% 7.60 22.78%
May 5.97 6.84 14.57% 7.23 21.04%
Jun 5.35 6.05 13.08% 6.36 18.94%
Jul 4.7 5.19 10.43% 5.55 17.98%
Aug 4.27 4.65 8.90% 5.04 18.08%

Pl clarify whether PVsyst team has done any comparison of actual gain vs PVsyst estimation for trackers and has done any validation of the inbuilt tracking algorithm .

Pl note, the parameters such as tracking angle, pitch and orientation were maintained same as per site condition


Thank You