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Transmission Trees Factors In Pv*sol


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I was wondering how does the PV SOL apply the light transmission factors (degrees of transmittance)?

I understand that when it comes to solar thermal systems and T SOL, the light transmission factors are used to reduce the amount of solar radiation passing through a tree object.
But what about PV SOL? If I understood correctly when checking for horizon shading for PV systems, it is shading of the actual AC output that is taken into account, not the solar radiation. That is: if certain portion of the horizon is shaded by an obsutrction tree the AC output that this certain portion of the horizon yields is subracted from the overall annual AC output.
So how are these light transmission factors taken into account at PV systems?

Thank you for the reply.

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Hello Bernard,

we need some more information, with which program

(PV*SOL pro, PV*SOL expert, PV*SOL advanced, PV*SOL or PV*SOL premium)

and which version of the program you are working. If you mean PV * SOL premium, are you talking about the entry of a tree in the 3D world or do you want to enter a tree in the horizon line?

Kind regards 


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  • 4 months later...

Dear Mr. Rainer,

I apologize for taking me too long to reply.

My question comes from a quote from a book: "Planning and Installing Photovoltaic Systems: A Guide for Installers, Architects and Engineers, Deutsche Gesellschaft Für Sonnenenergie (Dgs), Dec 2007.":




For shading caused by trees, a transmission factor is given:
- for coniferous trees: tau = 0.30
- for deciduous trees in winter: tau = 0.64
- for deciduous trees in summer: tau = 0.23

The transmission factor specifies how much solar radiation passes through the tree. It is taken into account in some simulation programs (e.g. PV*SOL)


Are upper mentioned default transmission indices still present in PV*SOL ?

Thank you for the comment, and again apologies for not replying on time.

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Dear Bernard,


In the 3D visualization you can display the seasonally varying transmittances (degrees of permeability) through the tree crown.


Proceed as follows:

  • Go to the Terrain view > Trees > Edit > Degrees of transmittance dialog. The designation of the active tree object always appears in the header of the dialog.

  • Enter a degree of transmittance in percent (0 - 100 %) for every month of the year.



These values are saved for every tree in the project.

  • Close the dialog with OK.

Best Regards


Your Technical Support & Servive

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  • 2 weeks later...

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