André Mermoud

Sorry, this is not possible in PVsyst. This would be very difficult to manage reflexions in a general way, as these are highly dependent on the geometry, the incidence irradiance and the surface's reflexion properties. By the way please remember that in a string of modules, the current of the worst cell drives the current of the whole string. Therefore if you don't have a perfect uniformity on at least one string area, you won't gain anything.

When you are in the shading 3D editor, in the main menu you have the option "Files" > "Save scene view" > "Keep this view for the report" You can manage your desired view in the editor (including shaded situation), and then use this option for the next issue of the report.

This reference of the AC loss with respect to Pmpp(STC) is a default value, it is a first guess proposed by the software for a quick estimation of a reasonable value. The real relevant value is based on the Rwiring value, that you should ideally calculate for your actual wiring installation. The resulting ohmic wiring loss is indeed expressed as a percentage of the Energy remaining at this point of the simulation. You can have a look on our FAQ "How to determine the Wiring loss Parameter", and also How to determine the parameters for external transfo loss ?.

Not in the present time. We will try to do that for a next version.

The simulation of PVsyst works on an hourly basis: one calculation for each hour, according to the meteo data for this hour (Global and diffuse irradiances, temperature). Now when meteo data are only available as Monthly values, PVsyst has to generate a synthetic hourly data file (random distribution) for working. See our FAQ What are Synthetic Hourly Data ?

Indeed, I don't know any systematic and significant differences of PR between different technologies in "usual" climates. Sometimes it may be more, sometimes less. Only the simulation can give an answer in a given climate, and you have an estimation of the respective irradiance and temperature losses. Moreover, the comparison results are not necessarily reliable as the module's performance parameters may be defined in different ways (Manufacturer-defined or default parameters for Rserie and Rshunt, etc). We don't have a detailed measurement report for each module (especially for low-light performance, i.e. Rserie determination). As you point out, it is possible to have less thermal losses with thin film technologies with lower muPmpp coefficients in very hot climates, but 8 to 10% seem a very high discrepancy.

When defining the batch mode, you should tick "Create Hourly File". If you do that, when exiting the batch mode dialog, the dialog for the definition of Hourly files appears after the message : "You have to define the contents of your hourly file". However you can also define the output CSV file by the button "Output file". On the batch parameters defintions sheet, you will have to specify a filename for each hourly file you want to create.

There are some few references for particular cases. But I don't know any general study nor methodology for the estimation of the soiling factor in any situation.

Many questions. The shading losses in PVsyst are of several kinds: - Loss on the beam component: the shading factor is the ratio of the shaded area to the total sensitive area. This may be pre-calculated in a table (as function of the sun's orientation) for a quick use by interpolation during the simulation. This may also be calculated at each simulation step (slower process). - Loss on the diffuse component: this is based on the hypothesis of an isotropic diffuse, and results from an integral of the shading factor for rays comming from all directions "seen" by the collector plane (orange slice of the heavens between collector plane and horizontal). This doesn't depend on the sun's position, and is therefore constant over the year. - Loss on the albedo component: same idea than for the diffuse: the integral is performed on the "orange slice" between the horizontal plane and the prolongation of the plane undergroud. The factor is shaded for parts below obstacles on the ground. There are also the shading factor "according to module strings" and "according to module layout" for the electrical mismatch effect, but this is another question. Now when you have a completely covered day (i.e. without any beam contribution), the shading loss in indeed determined according to the constant loss factor on the diffuse, what you observe in your results. In the results, you can get the 3 contributions (in hourly or monthly values): ShdBLss, ShdDLss, ShdALss, ie. shading losses on beam, Diffuse and Albedo respectively. And the corresponding shading factors (0 = full shading, 1 = no shading).

There is no way for doing this directly in PVsyst. However you can perform a simulation with the tracking option, and another one with a fixed plane at the "blocked" position. For each simulation you can produce an hourly file. In EXCEL, you can mix your 2 runs by choosing some hours with tracking and some hours with fixed plane.

I don't see what you mean. The images correspond indeed to the parameters specified. Perhaps you don't interpret them correctly.

The specificities are transmitted to the EXCEL database file, but only 4 lines (columns in EXCEL) are recorded. Sorry, we don't intend to offer possibilities of extending the "free" definitions of components in the present time.

I don't see the difference you do between the feed-in tariff and the export tariff. However this tool doesn't offer very detailed economic calculations. There are so many ways of doing business plans and getting economic indexes. We intend to improve it in the next months.

In the calculation version définitions, please use the button "Miscelleanous tools". Here you have an option for specifying a limit for the Grid power injection.

The diffuse model is not selectable. - When creating a synthetic hourly data file, PVsyt uses the model implemented by Meteonorm. We don't have much details about it. - When importing matao data - In all other cases when importing hourly meteo data without diffuse, PVsyst uses the Erbs model, implemented within PVsyst. Now on the report, just the denomination has changed. In the first versions 6, imported hourly diffuse was named "measured". But it is usually not the case, as in the great majority of the imported meteo data the diffuse is also obtained from a model. Therefore the new denomination is "imported".

It is normal that the electrical loss computed from the Module layout is lower than the crude approximation of the option "Shadings according to strings", which gives an upper limit. This is the reason of the parameter "Fraction for electrical effect", which you can adjust using the Module layout information. The relative position of the tables when defining the strings for the Module layout have no effect on the shading calculation. This arrangement is only a convenient way for defining all the tables at a time. We have improved this view recently. Since version 6.32, when the Pmpp of the shaded string is below the minimum voltage VmppMin of the inverter, the calculation searches for the second maximum within the voltage range.

For defining dummy trackers, you can specify a tracker with the same properties of your active one, and set the corresponding PVArray area to 0 (or almost 0) by defining the top and bottom inactive bands. But sorry, giving specific results for sub-systems is not possible in the present time. If we want to do that with some generality, this requires a rather big programming work for the specification of the required values, the accumulation during the simulation and the presentation of the results. If we define this just for one or two specific cases, we will of course inmmediately have requests for other cases...

Sorry, this is indeed an error in the translation file. For the Spanish and the Italian languages we have the inversion - Ausiliari (ventilatori, altro…) <=> Consumi notturni - Auxiliares (ventiladores, otros …) <=> Consumo nocturno Thank you for pointing this out. Such an error is almost impossible to detect by our own means. This will be corrected in the version 6.33.

The objective of the model is to reproduce the real behavior of the PV module, in any irradiance and temperature conditions. Even when the Diode Ideality factor is below its "physical" value of one, nothing indicates that the model gives erroneous results. Please see my work about validations of the model on our web site: "Performance assessment of a simulation model for PV modules of any available technology", Mermoud, A. & Lejeune, T., 2010, I would be very glad if someone does an equivalent measurement with modern PV modules.

The Auxiliary losses (formerly defined in the inverter's parameters) is now specified in the "Detailed losses" for the simulation. The values of the inverter are just used as default values for this parameter choice. The field "... from output power" means that the fans are switched on only when the inverter output power exceeds this value.

Sorry, by contract with Meteotest (the provider of Meteonorm), the meteonorm values got in PVsyst cannot be exported nor modified.

Yes, the PVGIS CMSAF data are an average over about the ten last years.

Thank you for pointing this out. This will be corrected in the next version 6.33.

I have never got nor seen this problem. Please send me your shading scene *.SHD (using "File" / "Save scene" in the menu of the 3D editor).

Please ask the manufacturer. I have not got a formal assessment of the duration of this increase of performance.