André Mermoud

This is a completely different question. If you don't avail of measured hourly temperatures in your datafile, don't define a column with monthly values. When temperature reading is not specified in the importing format protocol, at the execution of the importation the program will ask you for Monthly values (which you can take from another near site), and will generate hourly values using the usual model for synthetic hourly generation (see "What are Synthetic Hourly Data ?")

The transposition is highly dependent on the diffuse part. And the models for the diffuse are usually rather coarse. However the calculations in this tool are only meant for a quick evaluation when you are choosing an orientation. They are computed very quickly using a simplified algorithm based on the Montly meteo data (calculation of 3 average days for each month). Please don't use it for accurate evluations. The tool in "Tools" / "Transposition Factor" provides more accurate optimizations, evaluated on the basis of the hourly data, and for different conditions (different months, eventual horizon shading, etc).

The shading scene is stored within the "Calculation Version" file (*VCi). The opportunity of saving shading scenes as *.SHD is useful for intermediate saves when elaborating a complex scene, or for reusing the scene in another project.

Please exit PVsyst and renter it again: sometimes the internal lists are not refreshed.

The version 6 is a major release of the software PVsyst. Warning As in most complex software, deep modifications may lead to unexpected behaviors in parts which were previously stable. Although we intensively check before issuing each issue, it is really impossible to test or re-test every feature of the program, in any situation. Some improvements may have consequences on other parts of the program, and some parts will probably have to be updated according to these new features. Therefore you are asked for carefully reporting the errors you can encounter when using the program, by providing explanations of the problem, screenshots of the error messages, Log files, etc. From V 6.21, there is a powerful tool for reporting crashs of the program to the developers. When it appears, please don't hesitate to accept sending the error report to us. We also encourage any suggestion for the improvement of the software. We list here the main improvements by respect to the previous version 5: "Meteonorm Inside" - Direct search of any location on the earth, using the well-known GoogleMap tool. - Immediately get the monthly meteo values for any site, using the interpolating possibilities of Meteonorm 6.1. - Synthetic generation of hourly values uses now the Meteonorm algorithm, improved by respect to the old PVsyst algorithm. - Included import of meteo values from new databases, for example SolarAnywhere (SUNY model) satellite recent data covering the whole USA. - Transposition model on tilted planes: Perez model now proposed as default instead of Hay, leqading to an increase of 0 - 2% yearly sum according to climate and orientation. New Project management and simulation process - New Project management Dashboard, with direct access to all parameters, simulation and results in a single dialog. - Improved project management: copy, saving, transfers of calculation versions from projects to projects, copy of full projects. - Losses: new organization of the loss diagram. New losses like LID, System unavailability, Inverter auxiliary or night consumption, Light-soaking gains for CIS. - Batch mode for parametric studies: allowing to vary parameters in an EXCEL document, and get chosen simulation results of multiple runs as a table. Improved shading calculations - Direct shading factor calculation during the simulation (avoiding the interpolation uncertainties in the shading factor table). - Optimization of the calculation of the shading factor, allowing calculations of big PV plants without limitation to some hundredth of trows or trackers (factor of 10 on the speed). - Plants following the terrain, imported by Helios3D: analysis of the spread of orientations, management of the orientation average. Detailed electrical shading losses - Refinement of the "module layout" part, which allows to define the position of each PV module on the areas ("tables") defined in the 3D shading tool. - Modules arrangement in portrait or landscape, sub-modules in length or width within each module. - Attribution of each module to a given string and inverter. - Detailed calculation of the I/V characteristics under partial shadings in each Inverter input, either as pedagogic plot, and during the simulation for the determination of the "electrical losses" due to the shading mismatch. PV modules - Tools for specifiying low-light performances, and adjustment of the Rserie parameter accordingly. Low-light efficiencies may be included in the parameters in the database. - Modification of the default values for Gamma, when Rseries is not explicitely defined by the manufacturer, giving significant higher yields of 2-3%. - Import of a measured I/V curve for the establishment of the model's parameters. - Sandia model implementation, and comparison with the one-diode model. - New parameters: IAM profile in the module's parameters, Vmax(UL) for use in US, full tolerance definition, LID for crystalline and Light-soaking for CIS. - Easy choice of modules by manufacturers. Inverters - Multi-MPPT with unbalanced inputs - define main and secondary inputs. - Additional parameters: transformer specification, CEC average efficiency for US, auxiliary and night losses. - Easy choice of inverters by manufacturers. Software Installation and Background - New file organization, with clear distinction between internal database and custom files. - New data management, easy copy of the the full custom data set from previous installations, no problems of Administration rights anymore. - Certified installing package by PVsyst SA, registered in Windows. - Easy automatic updates. - New protection management. Some main novelties in the versions up to 6.22: - Multiple orientations, up to 8 different possible orientations, with correct shading calculations. - Improvement of the diffuse shading calculation with tracking (and especially backtracking) systems. - P50/P90 probability évaluation of the simulation result. - Power factor, grid power limitation. - Easier definition of 3D shading fields, directly with modules. Tools for easier Module Layout management.

For the near shadings, there is a Tutorial with an example in the help ("Overview" / "Tutorials"). For the Module Layout, we did not write a tutorial up to now, but the procedure is described in detail (step by step) in the Help of the version 6: "Project design" / "Module Layout" / "Summary of the Procedure".

I really don't understand what you want to do. - For analyzing the behaviour under different irradiance classes along the year, you can do an histogram (see for example in the results "Predefined graphs", "Incident irradiation distribution" or "Incident energy distribution"). - In hourly data you cand choose hours with a given POA Irradiance (for example 500 W/m2). Now if you want to manipulate the input hourly data for getting specific values, you can do this in an EXCEL CSV file that you will import using "Import ASCII meteo files". But be aware that if you specify for example an irradiance of 500 W/m2 (GHI): - If the diffuse is null, the system will receive a beam of 500 W/m2 * cosi/cosHsol (where i = incidence angle, Hsol = sun's height ) - But the diffuse is never null, and the resulting irradiance on the array will be the result of the transposition model.

Yes, PVsyst doesn't understand the dot within a filename (except the dot of the extension of course). Please simply remove the dots (and other eventual special characters) and everything should be OK.

As they are connected in series, all the cells in the module are submitted to the same current. Now if this current is forced over the Isc of a given cell (horizontal line on the graph above), this cell is reverse-biased and "consumes" power (positive current, negative voltage).

PVsyst puts a default value of 1.5% for the array ohmic loss. It is an reasonable initial guess for your first simulations of a system. But after that you have of course to estimate your real array wiring resistance according to your own cabling options. There is a tool for helping you in this task.

I just defined the "Unbalanced" option for inverters that I knew. Now most of the inverters of the database were proposed by their manufacturers before defining this feature, and they didn't mention this capability. You can of course define this by yourself in the Inverter's parameters.

No sorry, there is no possibility for identifying the PV module's parameters used in a simulation. This is indeed a weakness of the result's report of PVsyst. I have to think about some solution, but it is really not easy ... By the way the parameters of the PVsyst database are proposed by the manufacturers, and may also be "biased" (although I try to have some control on this, see What explains the difference of yield between different modules?

The PV array is sized in order to provide sufficient energy during the worst conditions along the year, therefore based on the worst days series in your weather data. Now if you diminish the autonomy period, the probability of "bad weather" series will significantly increase on short periods, therefor requiring a higher PV power. In other words: if you have 2 day autonomy, your PV array should be sized for ensuring the energy needs during the worst 2-days periods of the year. If you have 10 days, the probability of better days duting this time is much higher. In practice, PVsyst proposes an autonomy of 4 days. This may be slightly diminished in southern countries (but not less than 3 days), and significantly increased in northern countries with highly marked seasons. When you undersize the batteries, they will work more. Then, the price of the battery pack is not only the initial investment, but also related to the ageing, i.e. the number of charge/discharges (replacement costs). On the other hand, if you design a very big battery pack (more than 10 days), the PVsyst calculation will propose a reduced PV power, and the batteries may stay in discharged state during long periods, which is also not goos for their health. With the present cost of PV modules, it is wise to slightly oversize the PV array.

In the main menu of PVsyst, please use "Files" / "Import database components". Now if you want to put these files manually, a detailed description of the data structure is available in the help "Technical aspects > File organisation > Directories contents"

No sorry, this is not possible in the present time. Writing simulation parameters is a difficult task as there are many different ones, for each kind of system or simulation choices. The CSV hourly file refers to a given "Variant", and the parameters are on the report of this simulation report. In the version 6, you have now the opportunity of performing simulations in Batch mode. You can define some varying parameters on an EXCEL document, perform the concerned simulations and get chosen results on the EXCEL document, thus allowing for direct parametric studies in EXCEL.

As explained in the FAQ referenced above, you have many different strategies when mixing solar system, batteries and grid. In your case the batteries may be charged either by the solar array or by the grid. Which will be the conditions and strategy for chooosing one or the other source ? The batteries will probably feed only emergency circuits in your system, involving a double-circuit in your building. How to define these needs ? When the batterie are full the solar array will inject its energy into the grid - through which kind of inverter ? (probably a standard grid-connected), In case of a weak grid, how to model the grid unavailability ? etc... Such an installation and operational conditions are too complex for being defined in a general software like PVsyst in the present time.

In PVsyst you can define only 2 different orientations. In the "Orientation" dialog, please choose "Heterogeneous fields".

In PVsyst all angles are expressed in degrees.

Please have a look on the FAQ What is the basic concept of Inverter sizig ?. And also use the graph when pressing the button "Show optimization" in the System definition dialog.

This drawing in the Wiring loss part is only meant for showing the wire disposition. Each inverter shown here schematically represents a MPPT input. Please apologize for the mention: I programmed this drawing perhaps 5 years before defining multi-MPPT's for the inverters, and I did not update it...

I don't know how you obtained this curve. But of course, it is strongly dependent on the reverse charactersitics of the shaded cell. When I tried to establish experimentally this little (very rough) quadratic model by forcing a fixed reverse voltage to the cell, the measurements were difficult as when heating up, the cell's conductance increased with the temperature, therefore dramatically increasing the current and so on up to the destruction if I did not disconnect within some few seconds. It is probable that your shaded cell's voltage saturates at around -10 V or -11V, and this will indeed result in your observed curve. However this tool is a pedagogical one (for explaining the phenomenon). Fortunately the exact behaviour in this region doesn't arise in the real life, due to the protecting diodes. Otherwise you would often have cell's destructions due to Hot-spots !

This is related to the font size you are using in your Windows installation. Choosing "Small fonts" in your Windows installation should in principle solve the problem. If not please see Problems in the report format

No, in PVsyst each MPPT input (each sub-array) should be homogeneous (same module kind, same number of modules in series).

Please see in the FAQ : How to use inverters with very different MPPT (like Tripower of SMA) NB: In the new version 6, you have the opportunity of defining explicitely such a configuration (i.e. a "Main" and a "Secondary" input) with the concerned inverters.

In the "Orientation" part, please choose "Fixed tilted plane" and you can define the tilt and azimuth. There is no difficulty.