What are possible differences in yield between PVsyst versions ?

[André Mermoud]

The program PVsyst is continuously evolving, therefore it is quite unavoidable to get sometimes yield differences between versions.

We try to list some of them here (not exhaustive).

Version 6.33 with respect to 6.32

Module Layout calculations:

- When operating below the VmppMin inverter value, the simulation chooses the second maximum (instead of the voltage limit).

- For shed arrangement, the linear shading calculation has been refined, which affects the electrical loss calculation.

Version 6.27 with respect to 6.26

- The electrical shading loss calculation has been modified for shed arrangement: there is now a threshold in the shading factor for activating it.

- The AC ohmic losses after the inverter (wiring, transfo) are now affected by the power factor (divided by cos(phi)**2).

Version 6.26 with respect to 6.25

There were 3 modifications affecting the yield in this version:

- The interpretation of the muPmpp value as specified by the manufacturer: see Temperature behavior of the one-diode model . This induces a slight diminution of the temperature loss (around 0.1 or 0.2%).

- Concerning crystalline PV modules of the database for which the Rs is not specified by the manufacturer: the default Rs value was previously based on a fixed Gamma value of 1.10. It is now fixed by asking a relative efficiency of -3% at 200 W/m2. This induces a decrease of irradiance losses.

- The metal resistivity (copper and alu) have been slightly revised (unperceptibly diminishes the wiring losses).

Version 6.09

The shading factor for diffuse now calculated for different tracking positions.

=> Slight modification with normal systems with shades, but addition of a significant shading loss for Backtracking strategy (see How is calculated the shading loss on diffuse with tracking systems ?

Version 6 by respect to V 5

The differences are listed on another post.