kjs55

I am currently running PVsyst Version 6.26. In order to generate a custom PVsyst .PAN file, electrical performance (I-V curve) measurement data are collected at various temperature and irradiance conditions and used to optimize the PVsyst one-diode model parameters Rs, Rsh, Rsh0, RshExp, and mugamma. I would like to have the option to directly enter the value of mugamma that is solved for instead of having to determine the temperature coefficient of Pmax (truncated to two decimal places) that yields closest modeled temperature dependence to the fitted value of mugamma. A less desirable option is to extend the allowable number of decimals places of the temperature coefficient of Pmax (gPmp) to beyond two. However, again this requires the user to have to find the correct value of gPmp to input (now up to three or more decimal places) that results in the best match to the fitted value of mugamma. This is already a tedious process for two decimal places and it would be much easier if the user could directly input the fitted value of mugamma per the above paragraph.

As of Version 6.26, up to three decimal places are allowed to be entered for the ASHRAE b0 factor if defined in the PVsyst .PAN file. If defined in the "Detailed losses" section of PVsyst, only up to two decimal places are allowed to be entered. Please fix this so that the number of allowable decimal places is consistent in PVsyst.

I noticed some problems with the truncation of critical diode model parameters (this list may be non-exhaustive): - Vmp and Voc are truncated to 1 decimal in .xls file (limit is 2 decimals in .PAN file) - Imp and Isc are truncated to 2 decimals in .xls file (limit is 3 decimals in .PAN file) - Rs is truncated to 2 decimals in .xls file (limit is 3 decimals in .PAN file)

Issues with user defined IAM profile in PVsyst V6.22 Trial #1 Run a .PAN file that has a custom IAM profile Go to detailed system losses Deselect "uses definition of the PV module" Select "user defined profile" The user defined profile edit text box fields are not accessible for modification (they are "grayed out") Trial #2 Run a .PAN file that does not have a custom IAM profile Go to detailed system losses Select "user defined profile" The user defined profile edit text box fields are not accessible for modification (they are "grayed out")

During system downtime due to "unavailability in the system" (new loss in PVsyst V6), the external transformer losses remain proportional to the square of the current even though the system is not operating and no current is flowing (open-circuit). I think the external transformer losses should be constant (not irradiance-dependent) when the system is not operating. I think this indicates that there is a bug (e.g. the transformer loss is calculated and applied before taking into account the system is down).

Operating PVsyst V6.12 It is also unclear what the categories "Mixed", "In length", and "In width" actually mean. It would be helpful if a brief description of the terms was added to the Help menu.

Operating PVsyst V6.12 It is uncertain whether the negative energy values correlate with the randomized dates / times when the systems is not operational. It appears that summing the 8760 hourly energy values (both positive and negative) in Excel yields the same annual value as what is reflected in the PVsyst output report. I would have expected energy production to be zero during the times when the system is not operating (not negative). Please advise as to whether this is a bug or not.