backtracking Modeling backtracking behavior as a summation of fixed structures with batch simulation

[Geovera]

Hi to all forum members

I am looking to simulate backtracking behavior as a summation of fixed structure items.

What I mean; 

• Perform a simulation with bactracking enabled to know the angle at each tracker time.
• Then perform a batch simulation with a sweep of all the positions(angles) that the tracker can be in.

Then process the information in a separate document, select the E_grid if the angle of each hour that comes from backtracking match with the respective angle in the batch simulation, and replicate this whole year

The problem I have is that when comparing the first and the last hours of the day, they give very different results to those obtained with backtracking, the rest of the numbers are kept in similar parameters.

Any idea why for the same time and the same angle, is the E_grid for backtracking different than as a fixed structure?

Any help is appreciated

 

[Michele Oliosi]

You are comparing relative differences, but the irradiance is very low in the morning and evening. What does it look like in absolute differences ?
Also, you mention a sweep of all the positions, but it is virtually impossible to have all angles. You must be doing an interpolation and sweep the positions with a certain interval? Possibly the interpolation causes some error, which becomes more important as relative values in the morning and evening due to the low irradiance.
Just a hypothesis, please let us know.

It is an interesting problem. What is the end objective ? A validation?

 

[Geovera]

Hi, you are right , we are using a step of 1º (120 simulations for a range of movement from -60 to 60 and what we do is to adjust the angle of the backtracking to the lowest absolute angle and before it, to avoid that a wider angle gives shadows.

I also think it can be caused by interpolation, I will make some tests.

we are a tracker company and we are internal validating the accuracy, the effect that has 1,2,3...5º degree deviation of the backtracking angle