André Mermoud

The shading factor is the ratio of the shaded area, with respect to the full sensitive area. Therefore it is 0 when ther is no shading. Please tell me on which page of the tutorial the shading factor is one for no shadings. I checked and didn't see anything like that. (NB: This was the case in very old versions of PVsyst (perhap's in versions <=4, I don't remember). In the shading factor table, the height is defined as the angle between the concerned direction and the horizontal plane.

PVsyst only treats the mix of 2 orientations on a given MPPT input. If you have 3 orientations, you should define an average between two of them. The results will not be very different.

The parameters (tilt, azimuth) should match between the "Orientation" part and the 3D shading scene of course. Wanting to do otherwise doesn't make sense.

If you read the instructions on the dialog in "Preferences", you will read this: "This choice is for use outside of a project (tools, database and new projects). The model choice for actual simulations is now defined in the project's parameters". The project's parameters are defined under the button "Albedo & Settings" in the Project's dialog. Sometimes reading the instructions in PVsyst may avoid loosing time...

This publication is named "Measuring and Modelling Nominal Operating Cell Temperature (NOCT)" Matthew Muller, NREL, Sept 22-23, 2010. It is part of the presentations at a Workshop dealing with PV performance and Modelling, held at Sandia Laboratories (Albuquerque) in May 2010. I don't know if it is publicly available.

This depends on your maximum backtracking angle (depending on the pitch and tracker's width). If this angle is between 45° and 55°, the limit of 45° will arise before the backtracking limit.

The backtracking calculation is made analytically. It is a very complex calculation, I have not established the algorithms for special cases like tiltd slope between trackers. The only way for doing this in full generality would be to use a successive approximation process at each hour. Now if you have an irregular altitude distribution (for example on a hill), the backtracking has to be computed according to the "worst case" tracker's pair configuration. It cannot be optimal for the full array. If you want a "real" backtracking for the full array, you have to compute the orientation of each pair of trackers independently.

This is a difficult question. For Africa and Europe, the PVGIS data are rather good for recent climate. For the USA, there are several sources, I don't know which is the more reliable. For the rest of the world, if you have doubts, you can also buy paid data.

When creating a synthetic hourly data file (from external monthly data), PVsyst uses the algorithm which is included in the Meteonorm program (DLL used in PVsyst). During this process, the program Meteonorm establishes the Diffuse component (from global) using the Perez-Ineichen model (also named DirInt). Now if you specify Monthly values for the diffuse, PVsyst will renormalize the Diffuse computed from the model, in order to get the exact specified Monthly sum.

Your project file (and probably the associated calculation verions) is corrupted. This usually arises when you try to read a file which has been elaborated from a more recent version of PVsyst. In this case you have to remove the corrupted files from your workspace.

The site of the projects should contain Valid Monthly meteo data. Thes data will not be used in the simulation, but are involved in several sizing tools. If your imported data are not complete (as it is your case), you should define valid and complete monthly data, what you can import for example from Meteonorm.

The shading factor is the ratio of the shaded area, with respect to the total sensitive area. For a same collector tilt, if the pitch increases, the mutual shadings (shading factor) will decrease of course. I don't understand the rest of the question. In the 3D construction, you can have a look on the shading factor using the "Animation" (button on bottom left).

The number of MPPT's is a physical feature of each inverter. In PVsyst, you normally use the MPPT features of the inverter. But in a pre-study, you have the opportunity to get rid of this and consider the inverter "as a whole", i.e. one MPPT input (option "Uses MPPT" unchecked). Now in one sub-array, you have to specify the number of strings, and the number of MPPT inputs used for this sub-array. For example if you have 8 strings, you can distribute them on 4 MPPT inputs. If the inverters have 1 MPPT, this will mean 4 inverters; with 2 MPPT per inverter: 2 full inverters; with 3 MPPT per inverter, 1 inverter and a third. You can use other MPPT inputs in other sub-arrays.

I had a look on your file: it is not an .OND file, but a copy of the EXCEL line representing an inverter. You could import it in PVsyst by "copying" the file contents, and importing it in the Inverter's definition (button "Paste from Table"). But you file is not valid: the Voltage definitions for the 3-voltage efficiency are missing.

For an update of your license, you have to contact our administration admin@pvsyst.com.

Yes you can easily import SolarGIS data into PVsyst. In "Databases", please choose "Import Meteo Data" and then "SolarGIS". The help gives a summary of all meteo data sources which you can easily import into PVsyst. Please see in the help "Meteo Database > Import meteo data".

This is a problem with the domes manipulation. We have corrected it for the next version 6.43, to be released on March 16th, 2016.

The Rule of thumb remains valid: if your system size is less than around 0.2 miles, you can use the Far shadings option. Now you can also use both options, and analyze the discrepancies.

The Solar geometry calculations are fully described in the help "Physical models used > Solar Geometry"

Please send us the concerned controller file (to support@pvsyst.com).

Everything is fully explained in the Help: "Project design > Grid-connected system definition > Power optimizers > SolarEdge Architecture".

The Hay model is fully described in the help: "Physical models used > Incident irradiation models > The Hay transposition model". For the Perez model, it is more complicated, you have to follow the original article: R. Perez, P.Ineichen, R. Seals, J. Michalsky, R. Stewart: Modeling Daylight Availability and Irradiance Component from Direct and Global Irradiance. Solar Energy 44, no 5, pp 271-289, 1990.

Please see our FAQ When starting PVsyst I get: "The application can not start because it is not signed by PVsyst SA."

This not yet possible. We are working on this. However if it is for example a factory rooftop, you can record a plane image from your Sketchup construction, and use it as a background image in the 3D construction tool of PVsyst.

Sorry, it is a "youth" bug in the version 6.42. You can use the tool "Degradation" only with a new calculation version, not with a calculation version that has been read on a file. This will be corrected in the next version 6.43.