Odd behavior / unexpected results- increasing tracker spacing (to infinity) continues to increase energy

[Pete]

Background:

I built a simple single inverter model to investigate energy vs tracker row spacing.  In all cases, I kept the array consistent and only increased the tracker spacing in increments of 0.25M.   I expected to see that annual energy would plateau at some point and not increase, indicating the MAX optimum space.  There is more to my analysis but, this is the background for the issue at hand.  As I increased from 6 through 8.5 meters, energy continued to increase.  I then jumped to 50 meters and the trend continued!  Similarly, I used 100M and the results continued to climb. 

I have no HV transformer or other losses and the consistent system definition below: 

[Michele Oliosi]

Hi, I would suggest looking at more variables. I strongly suspect that the dominant loss factor is the losses on the diffuse component. These will have a less sharp decrease than other losses, especially in the case of backtracking, which zeroes-out the direct shading losses.

You can take a look at ShdDLss and ShdALss.

[dtarin]

This doesnt look off but not enough info here. The difference between 100m and 50m is .07%. Between 8.5m and 50m, energy plateaus. Since you havent included those simulations, it looks linear there. 

Edited May 23 by dtarin

[Pete]

I fully expected energy to plateau as you mention dtarin.   Perhaps my variant comparison above was confusing- so I have added some annotations below to help better explain my concern.   At 50M, there should be very minimal row-row shading with of course the exception in the early  / late parts of the day.  To your point, we should not see an appreciable yearly energy increase. This "plateau does not occur until roughly 50m.

@Michele Oliosi I did add the suggested shading loss to the 8760 data and plotted in excel.  I do not see a significant change here.  I can share my model - can you suggest a method for file sharing?

 

 

 

 

 

Edited May 29 by Pete

[Michele Oliosi]

@Pete if you can send the zipped project (Export button in the project window) as well as your result tables (including the batch results file if you used the batch) to the email address support@pvsyst.com

As usual with these investigations, comparing intermediate variables and not just the final energy gives good results in pinpointing the main effect. If ShdDLss is not the issue, then we should look at other variables before and after this point, to see if the energy increase is due to a specific loss or gain along the loss tree. 

[Pete]

I have emailed the model.  @Michele Oliosi Thank you!