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Available area definition

In the first tab "Mechanical", you can define subfields, i.e. surfaces for receiving the PV modules, which we will name "sub-field area".

Each sub-field area is a rectangle-based area, in which you can include  "secondary rectangles"  of any size for defining areas "forbidden for modules". These secondary rectangles may be positioned on corners, or anywhere in the main rectangle (representing for example a window, a chimney with its shaded environment, etc.

This rectangle may also be transformed into a rectangular triangle, for example for representing a four-sided roof.

Within such an inactive "secondary rectangle", you may also redefine an active rectangle for receiving modules.

You can define as many "sub-field areas" as desired. These mechanical sub-fields areas, defined "geographically" on your building, are not related and should not be confused with the  "electrical sub-fields"  of the PV system definitions, corresponding to a set of module strings connected to one or several inverters.

For sheds arrangements, you will define one sub-field for each shed (or tracker if you have a tracking system). For several disconnected roof elements, one for each element.

Module arrangement

After defining your available area, you can push the "Set Modules" button, which will distribute the PV modules on this area. For this operation, you have several choices:

Then the program will tell you the number of modules which may be installed on this area. In the "General PV Array" information box, you have also the total number of modules to be positioned according to the system definition, and the number of modules left to be defined.

Now you can modify your inactivating rectangles, and the modules will rearrange accordingly.

If you have too many modules, you can delete some of them with the right button of the mouse (or restore them with the left button).

Attribution of modules to system strings

The "Electrical" tab allows to define the electrical properties of your PV modules layout, either for defining a wiring schema, and for future shading calculations.

First you should define the number of by-pass protection diodes  (should normally be part of the PV module definition in the database, but often not defined or not reliable: please carefully check this information on the datasheets). And you should define whether the sub-series of cells (protected by one diode) are cabled in length or in width in the module (useful for detailed shading calculations).

Now the program shows all the strings defined in your system (in all electrical sub-fields), and gives a representation of all modules in each string. These strings are numbered for the whole system, whatever the electrical sub-field.

You should attribute each positioned module to a given string. For this, please choose one string in the electrical representation, and you can distribute the modules corresponding to this string on the positioned modules by using the left button of the mouse. Use the right button for removing an attribution. The not-attributed modules in the electrical part remain white.

There is an option for showing the attributed string number on each module.

This figure may be used on site as a wiring schema.

Electrical shading effects

The shading effects are computed according to each corner of each submodule (part of module protected by one by-pass diode). One corner shaded is interpreted as 1 cell shaded, 2 or 3 corners as 1/3 or 2/3 cells shaded, and the 4 corners as a full shading. The effect of one or several shaded cells is indeed very similar, so that this approximation is quite sufficient.

The electrical shading effect is only applied to the beam component. In reality, even at bright sun there is a residual diffuse irradiance of the order of 15% or more.