Albedo and Diffuse Factor in horizon losses

[Gustavo Pianovski]

Hello,

I have two projects in the same location and the losses horizon shading difference is 1.4%. The horizon profile is similar.

In the first, I have the following factors:

• Albedo factor = 0.87
• Diffuse factor =0.96

The horizon losses is 0.4%.

 

 

In the second, I have the following factors: 

• Albedo factor = 1.00
• Diffuse factor = 1.00

The horizon losses is 1.8%.

 

 

Question:

1) How do these factors affect the shading calculation?

2) How can these factors be defined?

3) Where can these factors be set in PVsyst?

 

Thank you!

[Michele Oliosi]

HI, there seems to be a bug that shows the factors as 1.00 even in cases where they are not 1. The displayed values are just updated when you enter the "Diffuse factor" tab in the horizon window.

We will be looking into the bug.

They are in any case internal variables, indirectly calculated from the orientation and horizon profile. You cannot set them manually.

It is not equivalent to the far/shadings and horizon loss. These will in fact depend on details such as the exact weather data and diffuse to direct ratio, the sun trajectory, orientation of the tables, etc. This means that you cannot find a one-to-one correspondence between these factors and the far shading losses.