Explanation of "other limitations" options

[Sebastian.stan]

Hi Andre,

In "albedo - settings" -> "other limitations":

What is the difference between:

- "Discriminating orient. difference between shading planes"

- "Maximum orient. difference for defining average (spread) orientation".

The second one does not seem to do anything to my Helios3D model.

Am I missing something?

The help section points out to 3 completely different items:

- Max orientation between shading plane

- Heterogeneous fields: maximum angle difference for shadings

- Helios3D: Maximum plane orientation differences

Thank you,

Sebastian

[André Mermoud]

PVsyst has to associate each subfield to a given orientation specified in the "Orientation" part.

Now when you have a "normal" system, PVsyst has to "identify" the orientations by comparing the subfields. For grouping the subfields in different orientations, PVsyst needs a discriminating criteria which is the "Discriminating orient. difference between shading planes". When you have planes with very close orientations you have sometimes to diminish this parameter (default value = 1°).

Now with Heios3D systems, the different slopes of the baselines according to the hill slopes give a "continuous" distribution of orientations. With the preceding criteria PVsyst will find a multitude of different orientations.

Therefore when recognizing such systems, PVsyst regroups all the tables of the orientations distribution into one only average orientation, and will calculate the simulation using this average orientation (which is an approximation).

Now the parameter "Maximum orient. difference for defining average (spread) orientation" defines limits for this spread. Sometimes you have to extend these limits. In this case you should be aware that you will increase the uncertainties for the transposition model.

NB: the mention "Heterogeneous fields: maximum angle difference for shadings" concerns an obsolete limitation in the version 5, where the "Multi-orientation" was not yet available. We have to suppress this from the Help.