Historical evolution of the software

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Historical evolution of the software

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Of course any newly discovered error (and errors reported by the users) are repaired for each new version.

Also this contextual "Help" system is continuously updated, either concerning new developments, or according to the numerous questions of users.



In Version 6.0   (02/02/2013, Beta release)

The main novelties in the version 6.0 are listed in a separate topic.

Some modifications  may  produce different results than with the version 5. These modifications and their effects are listed here.


In Version 5.63 (21.12.2012) :

1.Revision of the synthetic generation of temperatures   (erroneous results in very sunny climates in Southern hemisphere)
2.PV module import from PHOTON database: didn't work with some international Windows settings
3.Comparison Measurements-Simulation tool: error since version 5.60 prevented simulation
4.Helioclim data import: timezone not defined in data => proposed according to Longitude
5.Path for data specified with diacritic characters in Czech MsWindows  => suppressed diacritic characters in the program's path
6.Securized initialisation procedure of the program.
7.In some installations (lack of Windows reading rights), the program crashed.  

In Version 5.62 (27.11.2012) :

1.Error in the calculation of DiffEff and Alb_Eff (info only: This is not used in the simulation).
2.Database update

In Version 5.61 (12.11.2012) :

1.Pumping systems: improved presizing, especially in limit cases (worked fine - Securized calculations in some exotic situations),
Corrected some little display errors.
2.Stand-alone systems: since version 5.54, sometimes the battery used by the simulation doesn't correspond to the one chosen in the "system" part;
then returning in "System" leaves the battery choice blank.
3.PVGIS import for African data in southern hemisphere: error of the longitude sign => problems with time zone definition.
4.Meteo checking tool: sometimes graph choice error with incomplete years.
5.Simulation hourly graphs: units sometimes not displayed in titles (especially Ah).

In Version 5.60 (05.10.2012) :

1.Measured data: generates 1 full year (with 0 values) when only one day data (worked fine - generated just the available data -  for 2 days or more
2.Measured array temperature checkbox: sometimes masked if Meteo of the project is changed
3.Triphased voltage drop after inverter: evaluation error 15% (display only)
4.Import of POA values: possibility of increasing the acceptance when the clear day model is overcome (specified in the hidden parameters)
5.Lower limit of monthly ambient temperatures: now in Hidden parameters
6.Report: the model used (Hay/Perez) doesn't appear correctly when the meteo is changed.
7.Loss diagram: possibility of increasing number of decimals of the % losses

In Version 5.59 (18.07.2012) :

1.Error freezing the program at PV module or inverter opening

In Version 5.58 (16.07.2012) :

1.PHOTON database: the site URL and format has changed =>

       update for reading by  Firefox, Chrome, Explorer

2.PVGIS import: doesn't work anymore with Firefox 13 (modif. of the data format)
3.Very undersized inverters: when Vmpp < VmppMin(Inv), overpower loss not accounted correctly
=> Output powers may be > Pnom(AC)  (marginal effect)
4.Single amorphous modules model: modif Vbi for very high Vmpp
5.Tracking tilted axis in Southern hemisphere: axis azimuth not correct
6.Helios3D import in Southern hemisphere: Base slope sign not corect
7.MeteoConversion process: abort when all dates are invalid (not read correctly)
8.Regulator dialog: improved warning messages management

In Version 5.57 (29.05.2012) :

1.Tracking, error when axis azim = 180° => Authorize negative tilt of axis,
2.a:Si-H (single) modules: model modification for very high Vmp
3.Read Helios3D:  parameter correction for southern hemisphere
4.Import of Meteo files: add date format possibilities
5.Load daily and monthly definitions: dialog and report errors
6.Transformer losses: values disappeared in some special cases
7.Some modified inverters in the database: read error for effic. 3 voltages

In Version 5.56 (16.04.2012) :

1.Read Meteonorm: problems (monthly irrad=0) near polar circle
2.Inverter 3-voltages efficiency: OK if 2 voltages identical
3.Inverter and PVModule export to EXCEL:
decimal dot or comma acc. to international settings
4.Monthly tables: errors in units for Yr and Ya
5.Report: corrections (economics) and improvements (shadings)

In Version 5.55 (21.02.2012) :

1.Wiring resistance in AC part:
Increased reliability for very high diameters, specific current limit
Indication of undersized wires regarding max. admissible current
New Help for the maximum admissible current acc. to IEC
2.Loss diagram: secured units (sometimes not well intialized: W or W)
3.Pumping: unreadable when too high losses for full tank.
4.Pumping: div. by 0  
5.Read Helios3D files:
6.Additional tag for not-grouping tables in sets of sheds
Increased tolerance for orientation mismatch (hidden parameter)
7.PV module definition: extended limits for big modules (CPV)
8.Additional securisation for projects over the polar circle
9.Legal time - Solar time limit: extended in hidden parameters (China sites)

In  Version 5.54 (17.01.2012) :

1.Modernize battery database, update with several battery models
2.Sheds with sloped base: error in southern hemisphere
3.US TMY files: accept measurements of specific years and leap years
4.Database update

In Version 5.53.2 (16.11.2011) :

1.Suppression of spectral correction in CdTe modules
2.Errors in measurement-simul. comparisions graph definition
3.Database update

In Version 5.53.1 (03.10.2011) :

1.Error when changing the meteo file in a project
2.Errors in some inverter's data (nominal current)
3.Database update

In Version 5.52 (29.08.2011) :

1.Final report: possibility of changing kWh <=> MWh
2.Display errors in financial part  (currency not updated)
3.Import of PVsyst standard meteo data: diffuse model not calculated, errors in dialog when temp. not defined

In Version 5.51 (25.07.2011) :

1.Error when defining orientation

In Version 5.51 (22.07.2011) :

1.ModuleLayout: Shading electrical calculation pedagogic tool. Manually put a shading surface on the array, and see the electrical effect
2.Define a standard file format in CSV for import of hourly data.
3.Direct import of Meteo data from Solargis and 3Tiers (whole world, for pay) in PVsyst standard format.

In Version 5.50 (06.07.2011) :

Development and distribution passing from the University of Geneva to PVsyst SA.

1.Errors in the Grid connected system with load definition (net metering)
2.Tables and graphs of Measured Global in Plane and Measured Array Temperature.
3.Errors in Vmpp plots (limits).
4.Database now includes 7'200 modules and 2'000 inverters.

In Version 5.42 (25.05.2011) :

1.Bugs fixes in Conversion of ASCII files (Daylight Saving Time, DNI import, etc)
2.Bug fix in the Meteo calculations in monthly values (since V 5.4)
3.Horizon import: updates for Format change in Meteonorm, dot accepted in filenames
4.Model used (Hay or Perez) now can appear on the report
5.Database update, slight modification for a-Si:H single modules modelling

In Version 5.41 (04.05.2011) :

1.Import Measured Temp. array in the meteo data and use in the sîmulation.
2.Some bugs when importing meteo data (DNI, diffuse when timestep < 1H, etc).
3.Revised and improved import of Helios3D ground data.
4.Improved plots of measured data.
5.Wiring of very big systems: increased cable max. sections

In Version 5.40 (01.03.2011) :

1.  Import of meteo data ASCII files. Bugfixes for some specific files.

2.Import of pure DNI data without Global Horizontal.
3.Time Shift when importing GlobH (for DiffH calculation), POA or DNI data.
4.Clear sky model improvement.
5.Module Layout: bug fixes.
6.Grid simulations with net-metering: variables and Solar fraction bugfixes.

7. Import / Export of all database elements modified by the user.

8.Export of LOG files as ZIP files for debugging.
9.New AutoUpdater tool for software and database updates.

Version 5.31 (15.12.2010) :

1.Import Helioclim data: diffuse was not defined.
2.Bugs fixes: loss diagram, Help in Meteo import, countries with Upcase.

Version 5.3 (November 30th, 2010) :

1.Help system: completely new CHM version, now fully compatible with Windows 7.
A PDF version is available on the site.
2.New tool for the Meteo data quality check  (Kt plots, clear days check)
Implemented middle-interval shift for optimizing treatment of  not-centered meteo data
3Importing meteo data from Global Incident (POA) measurements: bug fixed
POA measured value now in the recorded data
4.Concentrating PV module (CPV): definition with spectral corrections
5.Concentrating systems: complete revision of the simulation process / variables
6.Update of the loss diagram, also for concentrating systems.
7.Inverter definitions, some bugs fixed: 3-voltage reading, bi-polar sizing,
8.Heterogeneous fields: old files V 4.37 prevent simulations (0 everywhere)
9.IAM calculation on diffuse: also with customized IAM function

Version 5.21 (September 3rd, 2010 ):

1.Direct link for importing PV modules and Inverters from PHOTON database
2.Shadings: define a new object  (mansard, or roof-window)
3.Favorites choice in the main Database lists easier  (by right click).
4.Directory Names now accept accents and some special characters
(solving problems with Czeck Republic Windows XP installations).
5.Meteo data: the wind speed is now part of hourly values when defined monthly.
6.Inverters: still problems with 3-voltage efficiency definition (solved).
7.Sun-shields: bug during mutual shading calculations
8.Fixed littles bugs: printing of PR, soiling table in parameters, etc.

Version 5.20 (August 3rd, 2010) :

1.File organization and localization has been changed
Your working \Data\ structure is now in a writable area
(avoiding delocalization of files written by PVsyst under Vista and Win7)
2.Module layout tool for the geometrical arrangement of your system
3.SolarEdge architecture: special option for decentralized architecture with Powerboxes.
4.Fixed bugs in Inverter definition, Projects, Latitudes over polar circle, etc.

Version 5.14 (June 30th, 2010) :

1.On some machines, for unidentified reasons (firewall, proxy, ?)
the AutoUpdate function induces crash at the opening of the software

Version 5.13 (June 25th, 2010) :

1.Autoupdate: freezing at opening on some Windows installations (web access)
2.AC loss: now possible after inverter or after external transfo
3.AC loss: bug when identifying mono/tri situation
4.Heat loss default values: bug, not always possible to change value.
5.Stand-alone, economic evaluation: bug fuel consumption
6.Stand-alone, Available energy and Time fraction: bugs when very bad design
7.Simulation: Bug Hourly plots for some variables.

Version 5.12 (May 25th, 2010) :

1.PV modules definition:
- shows the apparent Series resistance  (Rsapp, different from Rsmodel)
- Efficiency plots vs. irradiance: display low-light values
- Improved parameter definition in the help
2.Still bugs for the automatic update (freezed the program in some cases)

Version 5.11 (April 27th, 2010) :

1.Thermal U value default definitions for some typical situations
2.Bug shed shadings, new feature according to modules
3.Load definition: lowered low limit to less that 0.05W.
4.Auto Updates should be operational from next version.

Version 5.11 (April 16th, 2010) :

1.Bug when importing some meteo data  (PVGIS and Helioclim)
2.Animation video file (*.avi) compatible with Windows media Player

Version 5.1 (March 19th, 2010) :

1.Automatic auto-update for new versions  (doesn't work well until V 5.14)
2.Tool for the analysis of electrical effect of cell shading:
Extended to several cells, in one or several sub-module (groups protected by one by-pass diode).
3.Generic (unlimited) shed shadings:   electrical effect of shadings on the first cell row and bottom string.
4.Mismatch: histogram for the statistical study of loss distribution.
5.System design reference temperatures: now part of each project.
6.2-axis tracking: shadings compatible with concentration option.
7.Help: tutorials for project design and meteo data.
8.F10 key for directly switching  english <=> local language in most dialogs.
8Helioclim data: updated tool according to the new web site data format.
9.Defined bi-polar inverters in the system design and simulation
10.Inverter: bug when efficiency not well defined
11.Heterogeneous fields: still bugs in area calculations and mixed fields.
12.Video recording of the shading scene now works
13.Stand-alone systems: bugs in regulator definitions and system verifications
14.Array voltage was not registred in the simulation
15.Export project tool: error warning, corrected

Version 5.06 (January 26th, 2010) :

1.PV model: Saturation current Io limit down to 0.1 pA  (equation problems at low temperatures).
2.Helioclim data: the provider of these data has modified the site's format
=> readapted the program for a compatible easy importation
3.Shading calculations sometimes freezed. Improve reliability of shading calculations.
4.Near shadings, elementary objects, autorized tilt < 0°.
5.System dialog: did not keep the defined parameters when re-entering the dialog.
6.Inverter database: terminated the update according to Photon Magazine 2009.
7.Vista and Windows 7 compatibility: Parenthesis were not allowed in the directory \program files (i86)\ proposed by Windows.

Version 5.05 (December 18th, 2009) :

1.Stand-alone systems: bugs in the Regulator dialog and the simulation process
2.Grid system sizing tool: still another deep revision for more conviviality
bugs with master/slave definitions (sometimes divisions by 0)
possibility of Strongly Oversized inverters (by modifying Hidden parameters)
3.Inverter for 3 voltages: still some little improvements

Version 5.04 (November 24th, 2009) :

1.Hidden parameters were not modifiable (bug).
2.Regulator definition had intempestive warnings, preventing using it.
3.Heterogeneous fields: compatibility and warnings   Orientation <=> Shadings
4.Tracking frames with N/S frame: the tilt limits were not active
5.Inverter database: partial update (about 30%) from Photon Magazine 2009

Version 5.03 (November 2009, 10th) :

1.Corrections in the Grid-system sizing tool (MPPT inverters, not yet perfect !).
2.Some background colors make things unreadable in Vista and Windows 7.

Version 5.02 (October 2009, 26th) :

1.System definition freezed when defining multi-MWc systems. No more limit to the system size.
2.Improved the system sizing tool.
3.Corrected further bugs in the report (sometimes over-printing at head of the page).
4.Improved the ordering tool (sometimes e-mails were not well sent, and we did not receive your order).

Version 5.01 (October 2009, 12th) :

1.We just discover a important bug: in some cases (synthetic generation without specified Diffuse monthly values), the Diffuse is very low, leading namely to over-estimated transposed values (GlobInc). Please reinstall this new version, and open the projects elaborated under V 5.0. If this occurs, the program will give a warning, re-calculate the meteo file, and you should re-simulate all your calculations for this project. Please discard the old inputs of such erroneous projects.
2.Help improved for system design and inverter sizing.
3.Bugs in the report of the Heterogeneous multi-orientation fields
4.Module database completed for all modules references in Photon Magazine 2009 (now about 5'300 modules).

Version 5.0 (September 2009) :

This is a major modernization of the software. Many internal mechanisms have been improved since more than 2 years of development  (in parallel to version 4.xx updates). Therefore there may be bugs which have not been detected during the development. Please be so kind as to report them carefully to the authors.

1.Multilanguage: the simulation report was already available in several languages, but now the software itself is (partly) available in  English, French, German, Italian, Spanish and Portuguese.
This is not yet a full translation: only the most used parts - especially regarding grid connected systems - were translated up to now. This is a very time-consuming job (more than 200 dialogs, and hundreds of information/warning pieces to the user), and we will continue it progressively. On the other hand we don't intend to translate the Help at the moment.
2.Multi-fields: you have now the possibility of defining several field types for a given project  (with different PV modules or inverters, number of modules in series, etc). Their parameters are detailed on the final report, but the simulation results concern the whole installation.
3.Inverter: their definition includes many parameters which were not operational in the simulations up to now.
Multi-MPPT devices: you can define a specific sub-field for each input.
Possibility of Master/Slave operation: the Inverter's cascading is taken into account in the simulation process.
For some models: power limitation when running under a specified input voltage, is now taken into account.
Efficiency profile for 3 different input voltages.
4.Heterogeneous orientations: systems with 2 different orientations may now involve different sub-fields in each orientation, and/or a subfield for which the strings of a given inverter are distributed on both orientations (with mix of the I/V curve for correct calculation of the MPP).
5.Database management: the big lists of components stored as individual files, which took very much time to be loaded in the previous version (and sometimes caused bugs) are now replaced by centralized databases (CSV files). This results in an immediate access, and facilitates the updates of the DB of the software. Only the files you are creating or modifying by yourself will still be stored as individual files as before. This concerns:
The PV modules (which should approach 5'000 modules in the DB of 2009),
The inverters,
The geographic site database 5of which the lis shows now the source of data).
6.Favorites: you can now define a list of your favorite components in the database, which drastically simplifies the use of big component lists.
7.Near Shadings: the full dialog and tool have been improved. You can now:
Easily read and write a scene or a building directly from the 3D tool.
Multiple selection allows to define groups of objects, that you can replicate or save on a file.
Define/fix  the characteristics of the view you would like to appear in the final simulation report.
Register the shading's animation as a little video.
8.Special tracker devices with PV modules rotating on a tracking frame (with either N-S or E-W axis), are defined as special shading objects (with database of existing devices).
9.Shading of thin objects, like electrical wires or handrails, is now possible by weighting their effect on the "Module shading" part of the shaded areas.
10.Shading on strings: you can put a weight on the effect of the shading according to strings, in order to better approach the real shading effect on the electrical production (not only an upper limit) in the simulation.
11.Import Horizon profiles  directly from  Somletric SunEye, Carnaval software, Meteonorm.
12.Synthetic hourly data generation: the diffuse part may be renormalized to specified monthly data when available. This was not possible in the previous versions.
13.Improvement of the sizing tool for grid systems.

You have now the possibility of specifying either the nominal power, or the available area as starting point.

The software indicates the required ranges for the number of modules in series and in parallel.

A new powerful window shows all the constraints when sizing a field, i.e.

The voltages of the operating array with respect to the inverter's specifications,

Histogram of the waited power production of the array, compared to the inverter's nominal power.

Estimation of the overload losses (and visualization of their effect on the histogram).

This tool allows to determine precisely the ratio between array and inverter Pnom, and evaluates the associated losses.

14.The default losses management has been improved, especially the "Module quality loss" which is determined from the PV module's tolerance, and the mismatch on Pmpp which is dependent on the module technology.
15.Losses between inverters and grid injection have been implemented. These may be either ohmic wiring losses, and/or transformer losses when the transformer is external.


Version 4.37 (June 2009) :

1.Changed the program for the installation. The old one was no more compatible with the new ServicePack 3 of Windows.

Version 4.36 (April 2009) :

1.CdTe modules: the module definitions of the old database are affected by the new recombination losses.

=> Recreated files in the database for all CdTe modules, including recombination term according to our recent measurements at the University of Geneva.

Version 4.35 (March 2009) :

1.Import of Meteo data:

 Bug in some new files of Meteonorm V 6.0  (containing leap years)

 Bug in some TMY3 files (date recognition)

2. CdTe PV modules: according to our detailed measurements:  possibility of defining Recombination Losses.

3.Shading factor calculation (especially diffuse): bug when the plane azimuth is very unusual (north in Nordern hemisphere).

Version 4.34 (February 2009) :

1.Database: PV modules from manufacturers (especially many amorphous) and new inverters.
2.Tool for analysing shading of one cell in an array: Improvements, shows now shaded I/V charact. and Pmpp loss.

3. Meteo data import:

US-TMY3Import implemented  (1020 stations available)
Satellight:Bug temperatures when importing 5 years at a time.
PVGIS:Bug all months accounted as 31 days (overestimate 1.6%)
PVGIS:Now uses PVGIS site new interface, much more convivial
Meteonorm:Monthly files: still discovered a new format variant
Temperatures:Possibility of importing NASA data, always available.

4. Tracking tilted axis: error when axis azimuth not south.

5. Measured and Meteo data: little bugs (extended available date formats).

Version 4.33 (September 2008) :

1.Database: PV modules update from Photon Magazine 2008 and other manufacturer's data (over 3100 modules in the DB)
2.Loss diagram: still an error in the GlobShd evaluation  (but doesn't affect the final results)
3.Meteonorm import: tolerant to another (not yet registred) file format

Version 4.32 (July 2008) :

1.Database: Inverters update from Photon Magazine 2008
2.Loss diagram: incoherences in the shading and IAM relative losses  (only display in this diagram - simulation results were correct)
3.Ascii Meteo importing tool:

 Date management improvement,

 Site names beginning by "New" are now possible.

4. Search Edit for easier choice in big component lists.

5. Print Preview: easier navigation through pages.

Version 4.31 (June 2008) :

Some bugs fixed :

1. Satellight data import: Temperatures were not well imported.

2. PVGIS import: copy/paste did not work with some internet browsers.

3. Site/Meteo choice for Projects: generated erroneous meteo files

4. Simulation report: erroneous tables overwrited parameters (namely IAM)

5. Import of Meteo ASCII files: improvements for daily data and date formats.

6. Long component's lists: edit box for direct access to a given item

Version 4.3 (March 2008) :

1. Import of meteo data from multiple popular sources  (NASA, WRDC, PVGIS, RetScreen, Helioclim).

2. Comparison between several Meteo Data sources.  Developments and results in the Help.

3. Import/Export of "Site" monthly data from/to EXCEL.

4. Improvement of the Meteo hourly files management (site and comment now editable/exportable).

5. Implementation of Tracking with vertical axis, also useable with positioning of modules on a "dish"

6. Module temperature calculation: revision (new parameters, absorption, etc).

7. PV model for amorphous: parameter determination according to a specified  muPmpp  value. Adjusment of all triple-junction module parameters in the database.

8. Bug Tracking: azimuth sign error in south hemisphere: the tracking was reversed !

9. Bug Shadings, polygonal fields: rewritten the whole modules calculation.

Version 4.21 (September 2007) :

No new developments, only corrections of bugs.  The main ones were:

1. Tracking two axis: returns to Azim=0 when sun over +/-90°.

2. Near shadings: verification of interpenetration field-objects, some editing errors or improvements

3. New PV modules didn’t appear in the list.

4. Simulation: sometimes division by 0 with sheds.

5. Project situation dialog: improved copy of site <=> meteo.

6. Graphs: copy of the curve values to clipboard for exporting.

Version 4.2 (July 2007) :

1. Improvement of the navigability in the 3D construction tool, copy/paste of an object from one variant or project to another one.  Automatic verification of the Field interpenetration (or tangency) with another object, which may prevent good shading calculations.

2. Backtracking strategy with all tracking systems, involves tracker width and distance definitions.

3. Sun-shields definition in the 3D tool; also with backtracking, which may considerably improve the sun-shield's performances.

4. High-Concentrating systems simulation, associated with 2-axis trackers; adaptation of the simulation process and loss diagram.

5. Long-term financial balance tool, including several Feed-in tariff strategies (day/night or seasonal variations, feed-in and self-consumption tariffs, etc) and system ageing.

6. Soiling parameter included in the simulation and loss diagram, with possibility of defining monthly variations.

7. Direct import of meteo values from NASA-SSE database over the whole earth (by 1°x1° cells), and practical procedure for importing meteo values from WRDC database, especially for countries where METEONORM data are scarce.

8. Improved the model for amorphous PV modules, especially safety of parameter boundaries, and behaviour presentation to the user.

9. Improved the Project dialog and choice of a site/meteo. Improved compatibility checks between the project's site and hourly meteo. Extraction/edition of the site geographic properties within an hourly meteo file, which was not possible up to now.

10. Database update, with PV modules and inverters of 2006/2007  (now around 2250 PV modules and 770 inverters).

11. Adaptations for Windows VISTA OS, especially concerning the visual interface. All other functions seem to be perfectly compatible.

12. Introduction of many "Logs" in the program, in order to facilitate the debugging of user's problems.

Version 4.1 (January 2007) :

1.  MultiLanguage

The Simulation output reports are now available in French, German, Spanish, Italian (useful for presenting the PV system characteristics to customers).

Please contact the author if you wish to implement yourself a translation into your own language (you should have a good knowledge of the technical terms used in the PV technology).

2.  Windows user's rights compatibility

The DATA structure has been modified for compatibility with the user's rights protections in Windows. A user without writing rights can now copy the whole DATA structure for use in his own writable area. Data may be shared - or not - between different users of the machine.

3.  Files and projects transfers

Archiving or importing projects, as well as database updating tools have been improved.

4.  Bugs in special shading parts

Several "youth" bugs in newly developed features (often on special requests of users) have been fixed. Especially in the Shading part, concerning tracking mechanism as well as sheds with a tilted baseline or double-orientation.

Version 4.0 (June 2006) :

The main new feature in this PVsyst 4.0 version is the study of Pumping systems, which involves complex developments which may be not quite safe in this first issue.

1. Pump Model

Development of a general and original pump model, suitable for use in PV applications.

This should be suitable for any type of Pump or Motor useable in PV systems.

This should describe the operating of the pump over a large Electrical and Hydraulic domain, encountered in PV conditions.

Its parameter should be available from usual pump manufacturer's datasheets. For a given pump, the model may be specified using several kinds of original data.

Its accuracy over the whole domain has been checked for some pumps using measured data.

The defining dialog shows graphics of the behaviour of the model, as functions of all relevant variables.

The pumps database is still limited to about 20-30 models; only one manufacturer has answered our request for datasheets…

2. Controller / Converter device for pumping

Model for a new controller for pumping systems, including the System Configuration controls and Power converter.

A default controller is proposed for each system configuration, with parameters automatically adjusted according to the system for optimal operation.

3. Pumping systems

Three system types are proposed: Deep well, Pumping from lake, pond or river, and Pressurisation system;

For each type, several system configurations are possible: Direct coupling (with eventual improvements like booster, pump cascading or array reconfiguration), with Power converter (MPPT or Fixed V), or battery-buffered.

Water needs and Head characteristics may be defined in yearly, seasonally or monthly values.

4. Presizing tool for Pumping systems

As for stand-alone systems, a  Pre-Sizing tool has been developed, which proposes a PV power and Pump power sizing, according to the location and meteo, user's needs and LOL requirements.  This simplified model takes the pump technology and system configuration into account. It also proposes a very rough estimation of the costs.

5. Detailed Simulation

The design of the pumping system - rather complex with such a number of pumps and system technological aspects - is assisted by numerous sizing propositions, and helps (advices, graphs, blocking of uncompatibilities, etc) when choosing the system layout and configuration.

The hourly simulation accounts in detail for all features defined for the system, and is specific for each configuration listed above  (direct coupling, with converter or battery).

As for the other systems, a detailed engineer report explains all parameters and results of the simulation. All the losses and mismatches along the system are quantified, and visualised on the "Loss Diagram", specific for each configuration.

6. Help for pumping systems

The development of this Pumping tool has brought a deep understanding of the PV pumping systems problematic, and the operating / efficiency limitations inherent to the numerous possible solutions.

This Help describes in detail the implemented models, and sets a broad panel of the different available technologies, as well as delimits their implementation boundaries.

7. Heat transfer factor for thermal losses of PV array

Some users has pointed out that the proposed parameter accounting for wind velocities was not correct and lead to underestimated thermal losses. There is a new detailed discussion on this subject in the Help, and the program now advices to use wind contribution only when the wind velocity is quite well determined (now default value is  Kv = 0  W/m²K / m/s)

8. Inverters

Several parameter usually specified in the datasheet have been added to the inverter definitions. But none of them is used in the present simulation. Refinements of the inverter modelling are planned for a next version.

These new data have been added in the whole database when available. Almost 300 new inverters were introduced, many also suited for US market. The database includes now more than 650 inverters.

The 50/60 Hz frequency has become a choice criteria in the lists.

9. PV modules

The choice list shows a nominal (MPP) voltage of each module for making the system design easier.

The database includes now more than 1'600 PV modules.

The PV module definition dialog was improved and some bugs fixed.

Specifying the Voltage or Power Temperature coefficient is now possible also for amorphous modules.

10. Remarks in PV components

An unlimited text editor is now available for giving detailed descriptions of all the PV components.

11. Miscellaneous improvements or fixed bugs

-  Projects are now sorted according to their system type in the list.

-  The "Archive Projects" tool has been debugged and improved.

-  Summer/Winter Hour may now be taken into account when importing Meteo Data as ASCII files.

-  Some little bugs concerning the simulation, especially of stand-alone systems (Wearing state not computed, display errors, etc).

-  Loss diagrams: complete review, some corrections for losses coherence.


Version 3.41 (March 2006):

1. Automatic facility for importing "satellight" meteo data.

"Satellight" data are real measured meteo data, available free from the web for any pixel of about 5x7 km² in Europe, and for years 1996-2000. Their quality becomes better than any terrestrial measured data, as soon as you are far from more than 20 km of the measuring station.

2. Fix some bugs of version 3.4, concerning:

-  HIT PV modules model,

-  memory leakages and orientations in some shading special cases,

-  transposition safety when bad meteo values,

-  orientation choice dialog,

-  meteo ASCII conversion facility.


Version 3.4 (July 2005) :

1. New modelling procedure for the amorphous modules

This procedure was established and validated using the results of a research project performed at CUEPE, funded by the SIG-NER fund  (the  SIG - Services Industriels de Genève - are the Geneva Electric and Gaz Utility). This project included detailed long-term measurements of 6 PV modules in real conditions. It also gave a quantified validation of the standard model for crystalline and CIS modules.

2. Extended component database

Over 1'200 PV modules and 400 inverters are now referenced, with dates for identification of market availability or obsolete components. With such big lists, a mechanism for quick access time (and background process update) had to be implemented.

3. Near shading 3D tool

View of the shading scene in realistic colors (settable by the user for each object)  - instead of  "iron wires" representation - improves the understanding of complex scenes, and gives a much more attractive image of the project for the final customers. Animation over a whole chosen day also clarifies the shading impact of a given situation.

4. Implementation of tracking planes in the 3D shading tool.

Especially suited for the optimisation of heliostat arrays layout.

5. Review and improvement of the Simulation Process

Clarification of the losses at any stage of the system, extension to battery systems with DC-DC converters, rewriting of the heterogeneous field treatment , etc.

6. Detailed loss diagram

Gives a deep insight on the quality of the PV system design, by quantifying all loss effects on one only graph. Losses on each subsystem may be either grouped or expanded in detailed contributions.

7. Restructuration of the internal representation of the physical variables

These two last improvements were made possible thanks to a very deep revision of the internal data structure, in order to obtain more flexibility when using the simulation variables. This reorganization is transparent for the user, but allows now many enhancements of the simulation process, namely easy adding of new variables when necessary, including them dynamically in the simulation process according to specific system configurations (for example defining regulator losses when used in a battery system), or inversely discarding other ones when they are not relevant.

The old fixed variable set did not allow a coherent description of the system losses. Therefore simulation has to be performed again for getting the Loss Diagram on the old result files.

Caution: In spite of intensive tests, these deep modifications may have produced some bugs which have not been detected by the author. We thank the users for carefully reporting any misrunning or strange behaviour of the software to the author.  

8. Measured data – simulation  comparison

Improvement and debugging of the Measured Data Importing Tool, and the comparison between measured and simulated values. Improvement of the break-down data eliminations.

9. Daily and Hourly Plots of the load profiles



Version 3.3 (February 2004) :

1. Output results presentation and hourly plots

When displaying simulation results, the standard printable result forms are now directly accessible (while they were only available through the "preview" option in the "print" dialog up to now).

During simulation process, the program can store a sample of chosen variables in hourly values. This allows for displaying graphics in hourly or daily values, with several variables on the same plot.

Thanks to a very fast and easy navigation over the whole year, this offers a powerful tool for visualizing the instantaneous behaviour of the system all over the year. This helps, for example, identifying unexpected behaviours of the system in some specific operating conditions (for example, SOC and regulation states in stand-alone simulations).

2. Stand alone systems: implementation of MPPT and DC-DC converters

Up to now the stand-alone systems were only defined with a simple usual configuration (i.e. PV array directly connected to the load and battery through the regulator).

It is now possible to include a MPPT or DC-DC converter between the PV array and the battery/load. This converter is part of the regulator definition.

3. New tool for optimising Fixed Input Operating voltage

Shows the average power or efficiency of the PV array over a period (year, summer, winter), as a function of a fixed user's voltage. Shows ohmic and diode voltage drop effects.

4. Hourly profile for domestic use load definition

In order to better estimate the battery behaviour and wear. Automatic placement of lighting and TV uses to evening hours.

5. Improved irradiance clear sky models for very high altitudes (up to stratospheric).

For very special uses of the software.

6. Meteonorm input adaptation

The outputs format of the Meteonorm monthly files has been changed with the new version 5, and we had to match the reading format accordingly. This is not yet quite fixed (namely the new Meteonorm files don't include the Station name nor the geographical coordinates, which have to be input manually).

6. Databasse update

Added about 500 new PV modules, from the PHOTON magazine tables of February 2003 and February 2004.

Added about 40 Inverters from PHOTON magazine, march 2003.

Created  a  list of the main component manufacturers. This list is now selective, according to Manufacturers/Retailers and Component type.


Version 3.21 (November 2002) :


Shading factor calculations with partition in Modules chains: Some computation errors had been introduced with v3.2, fixed.

Horizon definition with more than 20 points now possible.

Minimization (iconisation) of the Program window now works.

Corrections for compliance with Windows XP environment.


Version 3.2 (July 2002) :

1. Thin film modelling

The main novelty is the special tools for the treatment of Thin film technology modules (a-SI:H, with tandem or tripple junctions, CIS, CdTe).

Up to now the program used the standard one-diode model, although it is not well-suited for these technologies.

There is no consensus up to now in the PV community on how to model these devices. The task of finding a general model is by far above our possibilities. It would require a big research project at the international level).

Nevertheless we carefully measured a single device in great detail (a-SI:H tripple junction) and tried to find improvements of the "standard" one-diode model. We found and implemented two adjustments, which can improve significantly the performances of the model:

- the Shunt resistance of the device is drastically increasing (exponentially) when the irradiation diminishes.

- the temperature behaviour, which is fixed as a result in the standard model, can now be adjusted at any desired value (often given by manufacturer).

For our test device, this diminished the modelling error (over a 4-month continuous measuring period) from about 11% to a very few (1 to 3%). But this doesn't take spectral effects into account (see the "Help" for further details).

Be aware that these are available tools, but we cannot assess parameter values for any modules or any technologies.

2. Orientation optimising tools

There is now an on-line tool showing the collecting performance as a function of tilt and orientation when choosing them.

Also for shed disposition, a new graph shows the annual yield curves taking shadings into account, for optimising the tilt, shed spacing and collecting/ground area ratio.

3. Components Database tools

Export and Import of PV components (PV modules, Inverters) between the PVsyst database and spreadsheets like MS Excel, allowing for displaying, input and correcting component data in tabular form.

Improved and securised default values for the input of new PV modules in the database, only based on Manufacturer datasheets. The Excel sheet shows clear detailed information about required, optional and PVsyst-calculated parameter.

Inverters: Automatic build of efficiency profile, according to Maximal and "Euro" efficiency data. This allows for a much more easy input of inverter data from Manufacturer datasheets.

Be aware that due to additional parameter, PV module and Inverter files written by Version 3.2 are not yet readable with anterior versions  (but old files can of course be read by version 3.2 !).

Update of the Database, which includes now more than 600 PV modules and 200 inverters of the market.

4. Miscellaneous

Near shadings: several little bugs and practical improvements. Improved the tools for manipulating and zooming the scene on the screen. Implemented the display of shadings calculated by points, when standard polygon algorithm fails.

Included a full example as tutorial for the "Measured Data Analysis" part, which allows for importing measured data in PVsyst, and closely comparing them with the simulated values.

Revision and improvement of the "PV array behaviour" graphic tools. Included a detailed Help.

"Perez" transposition algorithm (not the Hay transposition model proposed by default !) had a little bug which caused a discrepancy of the order of 2-3% on yearly results for vertical planes (and of course less for less tilted planes).

Revision of the tool for defining Currency Rates, which had some bugs.

Revision of the general displaying conditions when using screen settings with "large fonts". Many windows appeared not full developed, and had often to be resized. Also graphics and tables had sometimes very little fonts.

Reading of files without "Archive" attribute (which is sometime removed by some file managers) is now possible.


Version 3.11

Meteo: generating meteo hourly files in CSV format for export.

Meteo transposition tables: possibility of -180°..180° scale.

Horizon: automatic import of files from  "Meteonorm" and "HoriZON" software.

PV module: Pnom tolerance from manufacturer included as parameter.

Simulation: The user can now define a PV module quality loss, with respect to the manufacturer nominal data on which is based the PV module model. Therefore the results can be adjusted if necessary for Energy Yield Warranty.

Installations in Polar regions:  Possibility of defining meteo, and performing presizing and simulations for Arctic and Antarctic meteo (including months with zero irradiation).


Version 3.1 with respect to Version 3.01, 3.02 and 3.03

Database updates will be periodically available on the WEB site www.pvsyst.com. A special tool allows to dispatch the files into the PVsyst data structure.

Printed outputs: Printed results forms may also be exported as image, for pasting in other software like MS-Word. Allows to fully insert PVsyst results in documents (useful for example for sending them by e-mail).

Import of Meteo data: Import from Meteonorm software now quite debugged (except for bugs of the Meteonorm software itself with monthly data: the program tells you how to come over).

Direct import of US TMY files (240 US sites available free from WEB).

User's needs definitions: Graphs and printings are now available. A new feature allows for importing Load Profiles in hourly or daily values from ASCII files (e.g. for example from EXCEL).

Horizon definition: Diffuse and Albedo factors are newly introduced.

Horizon treatment in simulation strategy has been changed: it is now equivalent to the near shadings treatment (i.e. included in the "shading loss" calculation).

Near Shading tool: Further debugged. Undo facility (up to 10 levels), Very useful new tools for distances and angle "measurements" on the scene.

Simulation: Losses: New parameter accounting for the real quality of PV modules.

South hemisphere compatibility: Fully debugged, with new azimuth definition (negative toward east, clockwise). Sunpath diagrams are now from right to left (negative azimuts, i.e. sunrise, are on the right of the graph, as the sun progression ...).  Therefore gives realistic image of the horizon drawing.

Measured data: Importing widely debugged, Possibility for ASCII lines of more than 255 characters, Data import is now possible with input Daily Values. Measured data with orignal irradiation measurements in the collector plane. Graphics and comparison tool are debugged and improved.


Version 3.0 (December 1999)  with respect to Version  2.21


The PVsyst software has been entirely rewritten, using the Borland DELPHI 3  platform  instead of the old Borland Pascal 7, gaining in user graphical interface quality and reliability, as well as in compatibility with most recent versions of the Windows operating system.

The user's interface has been redesigned, and navigation in the software was strongly improved, with the collaboration of the LESO-EPFL team. Introduction of a "Green line" for guiding the user in the project development.

Preliminary design: Implementation of this quite new sizing feature, for grid-connected and stand alone systems.

Project design: The Project organization has been simplified. Parameter definition and results are summarised in one only "Simulation Version" file.  Several valuable tools were added (including the sizing "expert" for building the system parameter).

Several new Tools which help understanding more deeply many PV system behaviours.

"Help" system, which provides a detailed contextual  "help"  by typing F1 anywhere in the program.