André Mermoud

This tool is not suited for importing shading objects of any shape, like a polygon. It defines a terrain area, i.e. an uneven surface. In this respect the terrain is defined as a set of triangles constructed on your 3D points. The order of the points cannot be pre-defined: it is set by an internal algorithm according to the points positions. There is no possible choice for that: this is a univoqie mathematical choice. This construction cannot be concave.

PVsyst doesn't allow backtracking with different tracker's altitudes. Even if you define pairs of trackers for the calculation of the backtracking angle, this doesn't ensure that you will have a valid backtracking between you pairs of trackers: you can have shades, or backtracking misorientation state without necessity. This is not a particularity of PVsyst, but the real world. There may eventually be a solution for keeping backtracking conditions with uneven terrain, but this implies evaluating a different orientation for each tracker, and the calculation becomes extremely complex, as all the tracker's orientations are interdependent. A company proposes such an algorithm, which requires informatic learning techniques, and doesn't guarantee the absence of shades in any situation.

How do you define your "Maximum export power" ? If it is a grid limitation, this is quite normal: when you have losses after the inverter, the inverter has to produce some energy more, for compensating the AC losses after the inverter and ensuring a specified power injected into the grid.

This is because you have already installed PVsyst on your computer previously. You have "burned" your Evaluation mode. Try with another computer.

If you want to obtain what you "know à priori", it is not the good way. Sometimes the real calculation gives defferent values than what you are waiting for. Now the optimization of the plane orientation for your site may be obtained in detail in "Tools > Transposition factor" (here, please press F1 for Help). However this optimization is different when you have a sheds (rows) arrangement, due to mutual shadings. For deeply understanding this, please use "Project design > Grid connected > orientation", and choose "Unlimited sheds". Open "Show optimization", and press F1 for explanations.

You can do that manually. It is very difficult to define an algorithm for filling the tables with any exotic constraints like this one.

This becomes very complex indeed. And the "recovery" through the transparency would be very limited due to electrical mismatch losses. Moreover the "recovery" would arise in winter, when the irradiance contribution is not very important at medium latitudes. We don't envisage to implement this in PVsyst in a previsible future.

In the present time the bifacial model of PVsyst is indeed limited to shed-like or tracking with horizontal axis installations, sufficiently large for neglecting the edge effects on the sides of ths system, as well as in front and behind it. However you can define a 3D scene (in sheds or trackers), and if you (and PVsyst) judge that this matches these hypothesis, PVsyst will allow to use this installation as basis. However for the bi-facial calcuation, it will construct a dummy "unlimited sheds" installation, as similar as possible to your effective installation. Please carefully read the help "Project design > Bifacial Systems > Bifacial systems procedure".

Perhaps you have used Half-cells modules ? We have corrected a problem in the Module layout calculation for these particular modules in the version 6.76.

This is indeed a bug. Which version are you using ? We have corrected such problems in some very specific situations in the past. Please send us the full project, using "Files > Export project" in the main menu. Send it to support@pvsyst.com, in order that we can analyze this problem in detail.

In the present time the bifacial model of PVsyst is indeed limited to shed-like or tracking with horizontal axis installations, sufficiently large for neglecting the edge effects on the sides of ths system, as well as in front and behind it. However you can define a 3D scene (in sheds or trackers), and if you (and PVsyst) judge that this matches these hypothesis, PVsyst will allow to use this installation as basis. However for the bi-facial calcuation, it will construct a dummy "unlimited sheds" installation, as similar as possible to your effective installation. Please carefully read the help "Project design > Bifacial Systems > Bifacial systems procedure".

The problem is perhaps what you are expecting... If the yield is higher, this doesn't mean that the PR is higher, as it is normalized to the installed PNom. If the PV modules have rigorously identical performances (same Low-light behavior, same temperature coefficient, same IAM), the PR should be identical. Now you don't tell us which level of differences you observe (in percentage). There may be a discrepancy: - If you have inverter overload: in this case the loss will be higher for the second system, and therefore the PR will be lower. - As explained in the FAQ Why is the Pmpp of my modules different from the specified value?, the Imp*Vmp at STC may be different from the PNom of the module. This will induce a distortion of the PR.

You can modify this limit in the Hidden parameters, topic "Miscellaneous: Meteo, Simulation, ... ", item "Minimun power for Module Layout Error" (almost at the end of the topic).

This is a worst case choice. Please carefully read the FAQ post How to adjust the design temperatures ?

Defining a Bi-facial module is obviously not sufficient. When you choose a bifacial module, in the "System" dialog you have a button "Bifacia system" for defining the full Bi-facial configuration. NB: The bi-facial option is only available with Grid-connected systems in the present time-.

I don't know what you are talking about. There are no attachments.

This path is the storage area of the program. PVsyst cannot write anything in this location, protected by Windows. You data are stored in your own workspace, located at C:\ Users \ YourSession \ PVsyst660_Data \ Now you can also use the tool "Files / Export components" in the main menu of PVsyst for directly export your files.

I don't know. Nobody has never reported such a problem. The export of projects works quite well, using "Files > Export projects" in the main menu. Please contact support@pvsyst.com and explain exactly what you are doing.

You cannot export Meteonorm data. Meteonorm is also a software, sold as such. By contract with the Meteonorm team, the use of the Meteonorm data implemented in PVsyst is reserved to the internal use within PVsyst. If you need data for other uses you should buy the Meteonorm software.

There is no specified limit here. The Temperature loss is related to the muPmpp temperature coefficient of your modules, and the array temperature TArray. It is evaluated using the one-diode model and the thermal model described in the help "Project design > Array and system losses > Array Thermal losses"

A monthly clearness index of 0.85 is considered as irrealistic by PVsyst. The limit is fixed to 0.82, however you can change it in the "Hidden parameters", topic "Miscellaneous: Meteo, Simulation,...". Now I have just tried to define the GlobHor in Kt units, and this works quite well: you can save your SIT file with these values. NB: In the "Import Meteo data" section, you have the opportunity of creating a file of all Clear days for any location.

You cannot export Meteonorm data. Meteonorm is also a software, sold as such. By contract with the Meteonorm team, the use of the Meteonorm data implemented in PVsyst is reserved to the internal use within PVsyst. If you need data for other uses you should buy the Meteonorm software.

In previous versions, it was possible to activate the backtracking even without defining the 3D scene, which lead to neglecting the mjutual shadin losses on diffuse. Now you have to define the system in the 3D scene. The pitch is specified in this 3D scene.

There is indeed a little limitation/error in the model of PVsyst. When the diode Saturation current goes below 0.02 pA, it is limited to this very low value, for numerical reasons in the model calculation. This may arise with modules of high serie resistance (close to the RSerei limit), i.e. low diode ideality factors (<0.95). It appears with very low temperatures (< -10°C). This inverses the muVoc coefficient below a limit temperature, ,but has a very low effect on the model results.

Basically the TArray corresponds to the cell temperature. If some people make a difference between Cell and Module temperature, this is mainly related to the way of measuring it. Please remember that a thermometer always measures its own temperature. If you put a sensor behind the PV module without insulating it, there will be a thermal flux between the cell temperature and the sensor, and from the sensor to the ambient, so that the sensor measures an intermediate value (not well determined). If you put some insulation, you block this flux and the sensor will measure the "real" cell's temperature (thermal equillibrium conditions). For such a measurement, after some optimizations at the University of Geneva (using a special module with an integrated sensor directly on the cell within the encapsulation), we propose to cover the sensor with a piece of polystyrene of about 7 x 7 x 1 cm3. This size ensures a compromize, i.e. a sufficient insulation, without perturbating too much the local Cell's temperature.