Electrical effect for thin film

[estewan]

Hi,

I would like to know if there is a recommended "electrical effect" configuration of the shadings for thin film modules.

I guess it depends on the orientation: http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1858&context=nanopub

I am considering linear losses for portrait mounting.

Best

[André Mermoud]

Yes, when the shade takes all cells of a string in the same way (as with protrait mounting in a rows arrangement), there is no electrical mismatch loss, and the "Linear" calculation (irradiance deficit) is perfectly suited.

The calculation of the "Module layout" part is only applicable for crystalline modules, i.e. with about square cells.

[denizurla]

Should we consider electrical mismatch losses, if the thin-film modules placed in landscape?

[André Mermoud]

For a row installationm if the cell strips are in landscape (not necessarily the modules: in some modules the cells are along the little side) this is indeed the worst situation and you will have a full electrical loss as soon as the bottom of the modules is shaded.

[Anabia159]

To this post I have a follow up question;

Is it so that the level of the horizon corresponds to the Z value 0 in the near shading 3D scene construction?

Or is the curvature of the earth taken into account?

Meaning: do we assume sun height 0 degrees and the Z value 0 to be the same in the modelling?

When making the 3D model, does my placement of objects in the Z direction have any influence on the shading, or is only the relative placement of objects important?

Just wondering if the same result will be given if object 1 is at Z = 0 and object 2 is at Z = -5 or if object 1 is at Z = 5 and object 2 at Z = 0.

[André Mermoud]

Yes the horizon of the 3D scene corresponds to a view "height" angle of 0°. This doesn't take the earth curvature into account of course.

However the horizon is not implied in the 3D near shading calculations (only in the "Far shadings").

The shadings of 3D objects ("near shadings") are always mutual shadings from nearby objects, and are indeed related to the relative altitudes of the objects.

However if you place the origin of your whole scene at -100m or +100 m will not change anything.

[SE2015]

So as far as the shading calculation goes, I figure I should partition rectangles corresponding to the size of 1 module?

Can anyone think of a better way? I imagine that most shading that is not inter-row shading will 'disrupt' some cells in an affected module, thereby immediately tripping the bypass diode, and therefore bypassing the whole module.

In cases where there is a ground-mount system with additional shading (like from trees or electrical poles) - then I am stuck. This is because if the system is installed well (i.e. the cells are perpendicular to the inter row shading), then I use "Linear" shading loss. BUT, as soon as a different shade is introduced on top of the inter-row shading... then "linear" should be supplanted by the 1-module-partition I describe above (only for those affected modules). So I haven't figured a good way of simulating this type of system yet.

Any ideas are welcome :-)

[Jen H]

I'm facing the same issue. Maybe we could set the fraction for electrical effect to 0% (quasi-linear shading) but use a non-zero thin object ratio. Then define all external shading objects as thin objects? This will keep the module inter-row shading as linear.