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Wrong amount of PV Generator Energy (AC grid)


Marcin

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Hello Valentin Team,

I`ve created  3D  project with bifacial  modules (east/west)  

I don`t know if i do something wrong or there is a problem in aplication but in "Calculation": PV Generator Energy (AC grid) probably calculates energy only for one side.

I`v done some tests and facade  configuration heading to west producing  the same amount of energy as bifacial setup heading to east/west.

Calculation works correctly in 2D.

 

Bifacial and facade projects included in attachment.

kWh2.thumb.png.5ac637d601a9f1ea3d27715397080bc6.png

 

Niemierzyno_1.pvprj Niemierzyno_1_proba_usun.pvprj Niemierzyno2d.pdf

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Hi Marcin,

in the 3D environment of PV*SOL, we decided not to calculate bifacial gains if we have east/west mounting structures like in your pictures on the left. We assume that there is no irradiance hitting the backside of the module, since the triangular space below the modules will be dark.

Also for facade structures, we decided not to calculate bifacial gains, since we considered them to be usually parallel to a vertical wall. But we just discussed it here and we will modify that in the future. Mounting structures of type 1 ("Tilting of modules") and type 3 ("Facade tilt") will calculated with the view factor bifacial model for inclination angles between 10° and 80°, and with the "vertical" model for angles between 80° and 90°. If the inclination angle is below 10°, no irradiation gains will be calculated.

But for now, if you want to calculate with vertical modules oriented towards East/west, just use the mounting structure type 1.

Kind regards,

Martin

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Thank you Martin for reply,

 

To clarify situation here. Right now i can`t make bifacial installation like on picture with title "Bifacial two sides" and  and proper Generator Energy calculated.

I can make it like on picture with title "Facade one side"  but this is not resolve my problem because i need installation with  90 degree mounting and modules on both sides.

Is there any workaround for now  to achive this ?

 

Regards

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Hi Marcin,

from what I see on the picture there and also on their website (https://www.next2sun.de), there are only two bifacial modules per section, one on the top and one below. I think we can see it very clearly here on this picture:

K%C3%BChe-zwischen-den-Modulen.jpg

This system can be easily modelled in 3D right now, with the help of mounting system type 1:

image.png

image.png

And, in order to get the vertical posts in the correct place, set the Support Points Distance to a value a bit smaller than the longer side of the PV modules.

image.png

 

Hope that helps, kind regards,

Martin

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  • 1 year later...
  • 2 years later...

Hello BorisG

1 hour ago, BorisG said:

just to make sure, does PVSol still not calculate bifacial gain for rooftop east-west tilt?

Where do you got this information from? Rooftop does not have any influence at all.

Just want to make sure this is getting understood correctly: The bifacial gains are calculated correctly!

We do have deviations regarding the shading due to neighbour modules for the shadows which are cast when looking from the backside of the module for East-West configurations with high elevations as shown above. In such a case shadowing from neighbouring rows is underestimated.
image.png

Kind regards
Frederik

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Hi Frederik,

my mistake, I should have been more clear.

I meant East-West tilted modules with a small tilt angle (10° in this case). Attached is a screenshot of a sim I did with two south-facing constructions to aproximate E-W and also get the bifacial gain. Although I´m not sure that the results are realistic in this case (depends on wether shading between the two orientations is taken into account)

Kind regards

Boris

Screenshot 2024-05-08 141420.png

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  • 2 weeks later...

Hi Boris,

thanks for the clarification and the screenshot.

PV*SOL takes into account the irradiation on the back of the module for bifacial modules with an inclination of 10 ° or more.
However, in the case of an east-west system, it can be assumed that no or negligibly little radiation reaches the back of the modules due to the opposite positioning.

On 5/8/2024 at 1:24 PM, BorisG said:

Although I´m not sure that the results are realistic in this case (depends on wether shading between the two orientations is taken into account)

Regarding the shading of the module surface (front side), PV*SOL takes into account the shading caused by the surrounding modules. The results should therefore be realistic.

Kind regards

Mikio

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