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Calculating shadings on a subset of the 3D scene

When working on big projects it can be useful to limit the shading calculations to only a smaller part of the system. In PVsyst this is currently called the partial shading calculation mode, not to be confused with shades covering part of the DC array, also known as "partial shading". Another useful option is disabling the casting of shades for some objects.

Shadow casting

It is possible to enable or disable shadow casting for each shading object of the scene. All objects cast shadows by default, except for the ground objects.

By disabling shadow casting, the object will stop projecting shadows on other objects BUT it will still receive shadows from other objects if it is a PV object.

To enable shadow casting, use the checkbox located at the bottom right corner of all objects definition form:

ObjectCastsShadows

You can also use the contextual menu from the objects tree:

EnableShadowCasting

This feature is intended to be used for multiple purposes:

  • enable shadow calculations for ground objects when they may have an impact on the results
  • disable far objects which you know will never generate any shadow on PV areas to simplify calculations
  • quickly testing the impact of a shading object without having to remove it from the scene

Partial shadings calculation mode

PVsyst offers an option to run the shading calculations only on a specific subset of all PV tables.

This can be interesting either because the whole scene takes too long to simulate or because you want to focus on a specific subset that has some particularities in design.

The results of this "partial" calculation, i.e. the corresponding shading factors, will then be used for the entire PV system, as an extrapolation.

To do so, you must first enable the partial shading calculations from the menu Tools > Use partial shading calculations.

EnablePartialShadingsCalculations

Once this is enabled a new group titled "Partial shadings selection" will appear under the "Groups and zones" panel.

PartialGroup

This group is managed like any other group except for the fact that it can only contain PV fields. Note that other shading objects will still be used for the calculation, provided their shadow-casting flag is enabled.

The final step for partial calculations is to add the PV fields for which you want to compute shadings in this new group. Please refer to the Groups of objects section for more information on groups management.

!!! warning Incompatibility with the "module layout" mode This mode can be enabled provided that the shading calculation mode is either "linear" or "according to strings". The "module layout" shading calculation mode is not yet compatible with the partial shading calculations mode.

Output in the report

When you generate a simulation report with partial calculations, the percentage of PV area used for the calculations is mentioned near the shadings details:

PartialReport