Calculations for trackers

[Nicolas T]

Hello,

I looked at information on the calculations done by PVsyst for trackers, it would be nice if someone could confirm if what I understood is correct or not :

• For the IAM losses and the transposition of the irradiance PVsyst uses the average orientation of the scene
• The tracking angle is calculated based on a table/pitch ratio, the same one is applied to all the trackers of a scene
• The orientation differences created by the topography are taken into account for the calculation of the shading losses (up to 8 orientations ?). Is it fair to say that the topography is considered for the shading calculation ? 
• For the calculation of the bifacial gain PVsyst considers that the scene is flat

Thank you in advance,

Regards

[Michele Oliosi]

• IAM losses and transposition: Yes, the average is used. Until now, trackers always have a single average orientation.
• I assume you are talking about the backtracking strategy. In this case, yes the same pitch and width information is given to all trackers in the scene. There is only a parameter which is defined for each tracker independently, the axis tilt. Trackers with different axis tilts will move a bit differently under backtracking. Regarding the pitch and width, they are defined in Tools > Backtracking managament.
• In fact the "up to 8 orientations" is only the maximum limit for fixed tilt orientations. It is not related to the shading scene nor to trackers. In all cases, the shadings are computing taking the full complexity of the shading scene into account, including the topography.
• Basically yes, the calculation of the backside irradiance uses an idealized flat and regular model of the tracker positions.

 

[Nicolas T]

Thank you !