André Mermoud

BIPV double glass modules behave in the same way as usual modules. I think you are talking about Bifacial modules, which are able to produce electricity from both sides of the cells/module. Please see my answer to the post Mono c-Si Bifacial modules

Yes. the limit is in the hidden parameters. In the main menu, option "Preferences" / "Edit Hidden parameters" / "Detailed Simulation Verification Conditions", topic "Shadings: Absolute maximum Shadings/Field Area ratio".

Yes of course, the sample is not sufficient. This test is meant for a one-year dataset, it compares the best days in the data with the clear day model for getting an estimation of the quality of the data (namely the solarimeter calibration). For the discrepance between data, please see the help of PVsyst: "Geographical and Meteorological data > Import from Meteorological data sources: Meteorological data comparisons".

There is no possibility of deleting components or meteo files in PVsyst. You should explicitely delete the concerned files (*.MET and *.SIT) in the folders c:\ProgramData\PVsyst\Data\Meteo\ and ...\Sites\ Please have a look on Where are stored my working data in PVsyst ?

I have heard that they had a crash disk, and that they are taking this occasion for renewing their site, running since more than 10 years...

Sorry, there is no facility for suppressing components in PVsyst. You can directly delete the concerned *.OND files in the folder C:\ProgramData\PVsyst\Data\ComposPV\Inverters\ For the data location, please see http://forum.pvsyst.com/viewtopic.php?f=17&t=4

In your first step, you have defined: - 4 inputs (which are just the connections) - No use of MPPT. You should check "Multi-MPPT capability" and then define 3 MPPT inputs here. - Save the inverter under another name. After that you can define a sub-array with 2 MPPT inputs (2 strings) and the second one with one MPPT input, and everything should be OK.

During sizing, the maximum voltage limits are to be applied to the Voc voltage, not Vmp (voltage in open circuit at low temperature) ! If you have defined a maximum area in your sizing conditions ("Presizing Help" box), the program will check it and warn you. You can simply increase this value if it doesn't correspond to your reality, or put it at 0 for ignoring it.

We are preparing a portuguese version for the version 6. It should be available within some few weeks/months. Ground-measured irradiance data for Brazil are rather scarce. In PVsyst, the NASA-SSE and perhaps Retscreen can provide monthly data. If you can obtain data from your National Meteorological Service, PVsyst provides a tool for importing hourly values in almost any ASCII (Text) format. The future version 6 of PVsyst will give access to the full Meteonorm functionnalities for getting meteo data at any place on the earth. The kWp is the definition of the PV installed power. The energy produced with this installation (expressed in kWh or MWh) will be the result of the simulation. It is not a sizing parameter. You can use the "Presizing" part for a quick evaluation of the energy produced by a given installed power in your situation (meteo, orientation). But don't consider the yield of this Presizing part as an accurate result !!! The definitive system should be studied within the "Project design" part.

In the "Project" part, "Site and Meteo", you can redefine the project's site and associated meteo. After that you can rerun the simulation for your calculation versions. If you had saved the previous simulation, the saved version will keep its results with the preceding meteo data.

Is your logo in BMP format ? Do you see it when importing it in the "Status and Activation" window ? Does the path to this logo (or its filename) contain special characters like accents ? If everything above is ok, please send me this logo file and I will check here.

I have found the problem. It is related to the Internationalization parameters of Windows. I have corrected it in the latest version 5.63. Hoping this corrects this problem for everybody...

PVsyst doesn't avail of a model for generating hourly values of wind velocity (I really don't know how to generate such data). Therefore the values cannot be imported from Daily values ,and the reslut is 0 I could indeed envisage to put the daily value as constant over the day. I will think about this for a next version.

The 3D shadings part doesn't recognize field orientations as "different" when the angle difference between their true orientation is less than 3°. You can modify this limit of 3° in the main menu "Preferences" / "Hiden parameters" / "Detailed Simulation Verification Conditions", topic "Shadings: max orientation difference between shading planes". NB: the "true" orientation is calculated in the 3D space by the scalar product between both orientation vectors. For example, if you have 10° tilt planes with 16° azimth difference, you have an orientation difference of 3°. This value is shown in the "Orientation" dialog, label "Angle between planes". NB: With such a low difference in orientation, you can also avoid using "heterogeneous planes" and choose a single average plane (say, at 8°oriention).

You can get such specific data from the companies SolarGIS or 3Tiers. If so, you should ask for the data in the PVsyst standard format. But these data are for pay.

I don't know exactly what you are doing. PVsyst cannot treat data of less than one day. If so the missing hours of the day will be filled by zero values. But in the Comparison tool (if you are using it) it is possible that the 4-hour sample leads to a crash. Please let me know the details of your problem (screenshot of the whole screen) when the error occurs.

The Photon database web format has indeed changed in June 2012, and this change has been taken into account since the version 5.58. If you reinstall PVsyst over your old installation you don't need a new code nor transferring your license. However if you have reinstalled it in another disk you should indeed ask for a new code.

You have to redefine your inverter as a device with 5 inputs, one for each string. After that you can define a system with 2 subfields: one with 4 strings (MPPT inputs) and one with 1 string. Please see "How to use inverters with very different MPPT input like SMA tripower ?"

Please explain what doesn't work with the import of PV modules. Be aware that the PHOTON database is not perfect. Sometimes some parameters are missing, so that PVsyst is not able to use the concerned module. Please carefully read the warning when importing the module. Which browser are you using ? Currently Internet Explorer, Firefox and GoogleChrome work quite well.

Yes of course. A single silicon cell has usually a Vmpp of about 0.5-0.51V at 25°C (up to 0.57V for the special Sunpower technology). The Sunpower modules of 435 Wp have 128 cells in series.

Did you read the first answer to this post ? What is still unclear ?

As mentioned in the help, we propose a model (energy balance) for the determination of the PV module temperature during the simulation, but we don't have assessed values for the parameters. The parameters Uc and Uv are to be specified by the user. They are highly dependent on the layout of the system and the wind measured values (just above the plant or meteorological at 10m). But we don't avail of reliable long-term measurements for these parameters in any conditions (free, insulated, with air duct, as function of the tilt, etc). The only values proposed are according to my own measurements on 2 or 3 installations, or the values proposed by a third party in the US for free-standing disposition: Uc = 25 W/m²·k, Uv = 1.2 W/m²·k / m/s But I am not able to provide evolution as a function of the tilt angle. To my mind, theoretical air circulation thermal models may help, but are not sufficiently reliable. This should be measured on-site (the parameters may be extracted from long-term measurements of TAmb, Tarray, Ginc and Vind velocity).

I don't have definitive answers. Which version are you using ? Until version 5.57, there were an error in the simulation process: when the Vmpp was lower than VmppMin (il_VMin loss), the overpower was not checked. This may have some effect in systems with low Vmpp value (by hot conditions). Since 5.58, this has been corrected: The overpower increases the Voper value, and is comptabilised first. Usually this brings the Voper over the VmppMin value. Now with highly oversized arrays and high Vmpp (more modules in series), you have the risk that the overpower correction leads to an operating voltage higher than VmppMax, and in this case the inverter has to stop completely (it cannot find a suitable operating point), leading to high overpower losses. The losses at very low irradiance are quite normal, I don't see where is the problem.

The exact term should be "Controller" indeed. I kept the term "Regulator" (from french) for historical reasons up to now. The functions of this device are: - management of the battery: cut the PV array when full, cut the load when empty. - eventually perform power management (MPPT or DC-DC controller). The inverter for delivering AC power to the user is not comprised in this device, and is not defined in PVsyst in the present time. The PVsyst load definition is specified in terms of energy needs. If you are using an inverter, you should take its efficiency and stand-by consumption into account externally.

The first assessment in red is indeed strange. It should be a warning in orange. The lower limit of 78 Strings corresponds to a PNom ratio (Parray/Pinv) = 1, which is a reasonable minimum. Usual Pnom ratios are of the order of 1.15 to 1.25 (see below). The upper limit is not clear, probably the specified available area. I have to check in the program. But the second warning “The inverter power is slightly oversized” is quite justified. Please see - the help "Project design > Grid-connected system definition > Inverter / Array sizing" (directly accessed by the little orange button right top of the box), - our FAQ on this forum What is the basic concept of Inverter sizing ?, - The tool "Show sizing" just next to your message. Now for the use of special inverters of the SMA series "tripower", please see How to use the inverters with very different MPPT inputs (Tripower of SMA) ?.