Partial Shading vs loss of earnings

[dekay]

I have set up an example project to check the partial shading of inclined systems with various spacings.

The field with 30° South shows 4,1% loss of sun hours. 

And this only effects 2 of 3 rows but may effect the whole string.

If I compare the 30° with a narrow interrow-spacing with a 30° setup with very wide interrow spacing The difference is huge (11,2 vs 1,2%).

From the figure above I would expect a loss of around 4%?

 

 

Anyone got an explantion or a thread were the huge difference is explained?

Thanks!

 

 

 

[developer_mh]

Hi dekay,

this is absolutely reasonable. The 4% that you see in the 3D environment is the frequency of direct shadows on the modules, not the reduction of energy yield per year. It serves more as an indicator whether or not a module receives shadow. 

The impact on the energy yield per year depends on many other factors, e.g.:

• How are the modules interconnected?
• When does the shadow occur?
• How high is the direct and diffuse component of the solar irradiance at that moment

This can only be determined in the energy simulation, after which you see the results that you showed us here.

On our help pages you will find some more detail about the calculation of shadows, the effect of shadows on PV modules and PV fields and much more:

https://help.valentin-software.com/pvsol/en/calculation/irradiation/

https://help.valentin-software.com/pvsol/en/calculation/pv-modules/

https://help.valentin-software.com/pvsol/en/calculation/pv-field/

 

Hope that helps, kind regards,

Martin