Near Shadings: Irradiance Loss

[how]

Hello,

I am doing the experiment test on the effect of near shading to the energy production of PV modules over a year.

Situation 1: I put the PV modules without near shading 3D scene, the loss diagram result shows that "Near Shadings: Irradiance Loss" is 0.3%

Situation 2: I put the PV modules with near shading 3D scene, but the building block never caused any shadow on PV module, the loss diagram result shows that "Near Shadings: Irradiance Loss" is 2.4%

Situation 3: I put the PV modules with near shading 3D scene, the shadow cover part of the PV modules in the morning (8am to 11am), the loss diagram result shows that "Near Shadings: Irradiance Loss" is 3.0%

I wonder to know why i adding a building block but dont have any shadow on the PV modules that can caused a 2.4% of near shading: irradiance loss. What is the parameter that affect the losses due to near shading.

Thank you in advanced.

[André Mermoud]

The shading is accounted for the beam component (the shade what you see), but also on the diffuse and albedo components, which are integrals of the shading factor over all the directions "seen" by the PV module.

[rouge26]

This makes sense to me as far as additional shading loss considered due to lower diffuse irradiance but could you expand on the Albedo effect. Is the Albedo factor from a nearby object necessary a loss? what if the object has a white high reflecting surface?

Thanks.

[bapossatto]

On 4/28/2017 at 5:38 PM, André Mermoud said:

The shading is accounted for the beam component (the shade what you see), but also on the diffuse and albedo components, which are integrals of the shading factor over all the directions "seen" by the PV module.

Dear Mr. Mermoud,

Considering the "diffuse shadows" losses, should I consider this fact in a PR test for example?

Because when taking into account the value of GlobInc for the determination of the reference PR, it would be ignoring the losses due to diffuse shadows that the pyranometer will measure during its operation. In this sense, I understand that it would be correct to use the value "GPOA = GlobInc - Near Shadings: irradiance loss + Ground reflection on front side" as a reference for calculating the PR.

Thanks,

Benhur Possatto