Near shadings and sheds |
  
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Near shadings and sheds |
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In PVsyst detailed simulation, the mutual shading of sheds (or sun-shields) can be computed in two different ways:
| - | By defining them in the "Orientation" parameters option. You have here to define general parameters of sheds (width, tilt, pitch, etc.) valid for the whole PV system, and the simplified computation is assumed to be "linear" (without electrical cells effects) and for unlimited length (that is, neglecting edge effects on both extremities of the sheds). |
| - | By explicitely defining a PV plane as sheds in the "Near shading" scene. In this case the computation accounts for shed edges, and a module partition can be defined. |
Please note that these two options should not be used at the same time, as the shadings will be accounted for two times !!!
Definition by the "Orientation" parameter shed option
This option is most suited when you have a field of numerous and little sheds (for example "one-module" wide sheds), sufficiently long as you can neglect the edge effects.
Nevertheless, if you have to combine such an array with other surrounding shading obstacles in a very big near shading scene, for which the "near shadings" calculation is prohibitive: you can use is a very special mode:
| - | in the "orientation" part, you still define "unlimited sheds", ensuring a generic and quick calculation of mutual shadings. |
| - | in the 3D near shadings part, you define an horizontal plane representing the ground occupation of your sheds. The shadings of surrounding objects will be computed on this horizontal plane, and the resulting shading factor will be a compromise. This is of course an approximation, but a good way when the sheds are so numerous that the near shading complexity and calculation times become prohibitive (usually in these cases of big plants, the row-to-row mutual shadings are largely dominating the shading losses). |
Shed definition in the Near Shading scene
The "Near shading" shed construction may be unfeasible with a very big number of rows (say, more than several hundreds). The computing time and complexity of the shading factor calculation grows with the square of the number of elements (however reduced with optimization techniques in the version 6).
When you define sheds in the 3D scene, you have to choose a fixed tilted or multi-orientation plane (not unlimited sheds) in the "Orientation" parameters.