Michele Oliosi

Hi ! Could you send us (support@pvsyst.com) your scene ? This would make it much easier to understand the geometry of your problem.!

There are basically two ways to do this. First of all you want to import your weather data into PVsyst. Then the easiest way is to make a PVsyst simulation with an output file. You can do so by going to the "advanced simulation" menu. There please define the "Output file". Among the outputs you can choose GlobInc. Once you are done, you should launch a simulation from the same "advanced simulation" window. The second way is to use the "meteo tables and graphs" window, which you get either from the "Databases" menu, or from a project by opening the meteo file. From there, you have a series of tools to display the hourly data, including the Global irradiance on a tilted plane (so you have to choose a plane tilt and azimuth). You can export the data after showing it in a graph or table.

Yes the "mixed orientation" option can be used with two orientations only. In the system window you can put them on the same inverter only if you put them on separate MPPT inputs. If not, then yes I would suggest to reduce the number of orientations to 2. Indeed, it may give a rough approximation of your output. You can also create the tables first, and then use the "orientation management" tool of the 3D scene. This will allow you to detect orientations automatically, with different tolerances. If you bring them down to two there, you may keep your 3D scene as is.

Are you using a cloud service on the folder you are storing your workspace / CSV file ? (e.g. dropbox, google drive, ...) If so please deactivate the synchronization before saving the file. Another option would be to save the files locally instead of a cloud-shared folder.

Hi linkeshd and thanks for the feedback. We will update the link in the help. When using the Sandia model for a model out of the database, one will apply the "default" parameters: b₀ = 1 , b₁ = -0.002438 , b₂ = 0.003103 , b₃ = -0.0001246 , b₄ = 0.0000001211 , b₅ = -0.00000000136 Of course it is generally incorrect to use these values.

Hi Bruno, No, for trackers we perform the transposition using only a single orientation value. There may be a way to compute this mismatch in some future update of PVsyst, but for now it would be quite difficult. You may get a rough estimate of the mismatch by using the fixed tilt option, but it probably requires to be quite careful.

Hi shubham, Yes you can do this. You can use the "multiple orientations" option in the "orientation" window, which lets you use up to 8 fixed tilt orientations. Then you can just choose a tilt value = 90° when you need it.

The shed to shed slope, is the slope in the front-back direction of your tables, usually NS direction. Your tables therefore all have the same orientation (tilt and azimuth) but are at different heights due to the slope. In the case of the baseline slope, we consider a slope along the bottom of the table, usually EW direction. Your tables effective orientation will be changed, since the orthogonal vector to your table surface does not correspond to the original nominal tilt and azimuth.

PVsyst does this rather intuitively. You can either consider the inverter as a whole and let PVsyst balance strings on inputs (good for balanced strings), or consider MPPT inputs individually. In the most simple case, for balanced strings, and if you are filling all MPPT inputs with 2 strings, you don't have to do anything special. You can uncheck the "Use multi-MPPT feature" checkbox to consider the inverter as a whole. For a more complex case, you should use the "Use Multi-MPPT feature" checkbox. In this case, for a given sub-array, you will consider single, or groups of, MPPT inputs and associate a number of strings to them. In each of these groups the strings are shared in a balanced way. In this latter example there are two strings on a single MPPT input.

Yes the latest version of PVsyst (7.2.12 at the time of this post)still assumes horizontality for the bifacial model. As long as you don't modify the parameter too far from the original 2° (it is an order of magnitude estimate, not a hard limit), the error should be minimal

As mentioned in the messages in red, the axis tilt needs to be horizontal or nearly horizontal to use the bifacial model. In your scene the average tilt is apparently 2.4°. The default limit in PVsyst is 2°. You can relax this requirement at Home window > Settings > Edit advanced parameters, but at your own risk ! Indeed, the bifacial model will anyway assume horizontal axis, so there will be a discrepancy (in the backside contribution) with the reality of your scene. This may cause some inaccuracies in the backside contribution.

Hi, Yes unfortunately at the moment it is not possible to use the bifacial model with several orientations. One way would be to do as you write i.e. split the system in two and join both results. However, this will likely overestimate the backside production : e.g. the East tables will cause shadings that impact the backface of the West tables, and vice versa. These won't be taken into account when proceeding in this way.

The thin object shading percentage is a modifier to the electrical shading factor generated by thin objects. Basically if thin objects cause a near shading factor F, the simulation will instead use 40% of F in the simulation (just as what happens with the global "Fraction for electrical effect). Once you define at least one thin object, you will be able to adapt both the main "Fraction for electrical effect" which is applied to all objects except thin objects, and the one for thin objects that is applied to the factor caused by thin objects only.

Hi, This will be taken into account in a future version, although not sure which. Most probably this will be added to a major version. I agree that it makes more physical sense. Thanks for the feedback !

Keeping a given ground surface area constant and filling the area with modules according to pitch and tilt needs is a more complex task than the optimization plots already available, and this is not available as a tool in PVsyst yet. You could use the batch mode for this. In the case of a PV array, it is possible to modify the number of rows, as well as pitch, tilt, and other parameters. One should then calculate, in order to prepare the batch file parameters, the corresponding number of rows for a given pitch. This is not implemented as an automatic function in PVsyst. Note that the batch mode can output several variables as a csv, so the analysis of the results on excel would be quite simple. I can see how this could be a cumbersome task. We will add a ticket to possibly offer this as a tool directly, and potentially simplify this procedure.

Hi In the shading scene, you can access Tools > Orientation management. There you should be able to manage the average orientations, by changing the tolerance. Alternatively you can also create the three orientations (in the "Orientation" window) before importing the scene. You should then be able to assign the fields using the tool above.

Dear allanfisica, You are right, there is a mistake in the help, we will update the values. Thank you very much for the feedback. This also allowed us to find a different bug in the software that alters the value of the temperature corrected PR by a tiny amount (typically ~ 0.001). We will correct this in an upcoming patch.

Hi, Actually one of the default outputs from the simulation is almost what you need. Since bin is the accumulated irradiance, you can simply divide by the bin irradiance (the x value) to obtain the number of accumulated hours. You can access the values by clicking on "Detailed results" > "Predefined graphs" choosing the right graph and then exporting the values. You can also directly obtain an hours accumulation from the "Meteo Tables and Graphs" window, accessed when viewing a meteo file in the database, or from the project. Hope this helps !

Hi ! If you have a specific project or reports, with two variants showing the differences, you can send them at support@pvsyst.com You can export a project via the main window : File > Export projects

The time of your lower screenshot is 16:15, while your 3D scene seems to have time around 2-3 pm. Please use this tool to set the right time in the 3D scene. Once the time is set, click on "apply". Please let us know if this improves the situation.

From what you say about the system, especially it being an east west dome system it is likely that the bifacial gain will be low. However someone with more field experience should formulate a better answer here. From the PVsyst side it is as you say: the bifacial model and hence the backside irradiance do not take into account the shading scene for the shadings, only the interrow spacing, size of the tables, and the orientation are used. Therefore 5% is likely an overestimation.

A disclaimer: my answer is just based on physical intuition, not on a specific study. Because of the mesh thickness it could be a bit worse than that for diffuse light. If you want to be on the safe side you can increase that factor. However the best course of action is probably to make some measurements on a test module to ascertain these losses.

This is one of the default plots. Once you have simulated your variant, you can choose this plot in the drop down menu. Incident irradiance histogram

Sorry there is no workaround in this case. This is especially the case with solar edge components, which have strict functioning rules.

Hi, The "[...]BatchParams[...].CSV" file is not the simulation output, but will contain the parameters to be varied and the different simulation runs. As such it is a very small file. You have to fill it with the values for the variables to be varied. Once you then press simulation (in the advanced simulation window) the batch run will commence. At the end you will have a file named "[...]BatchResults[...].CSV" You can also send us the file at support@pvsyst.com, if you think the file is wrong.