André Mermoud

This is indeed on our ToDo list. But I don't know when this will be implemented.

Yes of course you can experiment all these features in PVsyst. For discovering the features of the software, you can download it from www.pvsyst.com, and use it with all its functionnalities during 30 days for evaluation.

Please see the FAQ Can I define a system with highly undersized inverter ?

There are almost 300 UPsolar modules in the database. I can't find any error in the number of cells. Please tell which module is in error.

To my knowing, this works quite well in the latest versions.

With Meteonorm within PVsyst, yu can get meteo data for anywhere on the earth. See our FAQ Which meteo data are available in PVsyst ?

For a Centrifugal pump, when specified as Head as function of Flowrate, PVsyst uses a model called "similarity laws" (see the help "Physical models used > Pump - Model description > Pump model from Head (and P) as f(FR), fixed U or speed". This definition also requires to know the efficiency (or Power) as function of the flowrate. For all other input parameter configurations, PVsyst doesn't use any model. It determines any operating conditions (I, U, H, F) or (P, H, F) by an interpolation between the specified operating conditions. This may represent a rather complex calculation. See the help "Physical models used > Pump - Model description". You have a detailed description of the pump model in a document available on our web site: "Technico-economical Optimization of Photovoltaic Pumping Systems Pedagogic and Simulation Tool Implementation in the PVsyst Software", André Mermoud, 2006 Research report of the Institute for Environmental Sciences, University of Geneva.

The transposition models take indeed the albedo of the terrain in front of the plane into account. If you have snow, you can increase the albedo factor (monthly values) in the Project's definition.

Yes, the light-soaking gain of CIS modules take place progressively with the sun irradiance, and becomes fully effective after some accumulated dozens or hundreds of kWh/m2. But sorry, the manufacturers don't give more information about this time.

Portrait, landscape and U-configuration are taken into account with the "Module layout" detailed calculation, applied to each module in the array. You can have a look on the "pedagogic" I/V curves shown with this tool (button "Calculate > page I/V curves").

As we cannot control the contents, we don't distribute any training certificates to third-party training organizations.

The ambient temperature may indeed be lower on the water surface. However I don't know any study evaluating this effect. Now for the albedo, if you have rows (sheds) arrangement only the first row will "see" the albedo. For all other rows, the water surface is not visible. Therefore there is a shading factor of (n -1)/n on the albedo factor (n = number of sheds, illimited sheds hypothesis). By the way, however surprising it can appear, the albedo contribution of a lake (during the full year) has been measured as very low (much lower than the 0.2 usual coefficient).

The main simulation variables are explained in the help "Project design > Results". However this may not be completely up to date, we may have added variables which are not listed.

I can't explain how you can get a positive value (gain) for the overpower loss. If so, please send your whole project to support@pvsyst.com, using "Files > Export projects" in the main menu.

At first sight ... When cells are shaded in one only sub-string, the module current will be limited to half the normal current. As soon as cells are shaded in both sub-strings of one submodule, the submodule will behave in the normal way. NB: we don't intend to implement such a specific case in PVsyst, unles this becomes a general layout adopted by a signigicant number of manufacturers.

There is indeed an error in versions 4.46 to 6.52: when defining a not-south azimuth for the Single axis tracking object in the 3D scene, this is not taken into account in the simulation. This was corrected in the V 6.53.

0.041667 = 1/24. This constant means one hour in units of days.

The calculation is done for the hourly step. If the sun is apparent during 20 minutes, and below the horizon during 40 minutes (theoretical sun position), then the simulation will account for 1/3 of the beam component for this hour.

The calculation "According to module strings" is an upper limit. You can modify its weight by the factor "Fraction for electical effect". Please see the help "Project design > Shadings > Near Shadings: Main dialog > Partition in module strings". You get it by the orange questionmark button next to this option. You are strongly advised to use these buttons (or F1) when you have a doubt.

If you are able to do this simulation without defining a shading scene, this is indeed a bug (the error is not taken into account), we have to correct it.

Yes of course. The horizontal irradiance (usual Meteo data) is the normal input for the simulation. The POA values are computed from a Transposition model (Hay or Perez) for any plane orientation.

From version 6.40 to 6.42, the IAM profile was indeed computed with a cubic spline between point#2 and point#3, which may lead to an artefact curve depending on how the points are aligned (if Point#1 and Point#2 are 1). This could give a discrepancy up to 0.3% to 0.4% in some cases. Now all the points interpolations up to the first <1 are computed with a linear interpolation.

If you trust the manufacturer's parameters you can use them. The IAM measurements are very difficult. Please see our FAQ How to determine the IAM profile ?

For your configuration, you should define 4 strings in the width of the shed. With sheds arrangement (a full row of cells shaded), the by-pass diodes don't recovery any power and the full string production (for beam component) is lost. Please see our FAQ How to evaluate the effect of by-pass diodes in shaded arrays ?

This requires that you avail of data about the yearly variability of the meteo data for your site. You have a complete explanation about the P50-P90 concept in the Help "Project design > P50 - P90 evaluations"