Low GlobInc with one axis N-S tracker

[Emanuel Rodriguez]

Dear PVsyst Team,

I have run some new simulations with the new 7.3.1 PVsyst version and found some problems with the Global incident Irradiation. The system has 6MW and one axis N-S trackers, in its simulations reports the Global Incident (GlobInc) value is very close to the Global Horizontal (GlobHrz) irradiation, I am getting a +1.2% * GlobHrz gain now but previously I got around +23.4%* GlobHrz that sound more sensible.

I did an advanced simulation to check the hourly values. However, I cannot see any significant difference of GlobInc from GlobHrz during morning and afternoon.

Do you know what could be happening? It is like the trackers are not moving or moving very slightly.

I have attached 2 images showing the difference between before and after version 7.3.1 and a PDF showing the hourly values of the after version 7.3.1 where you can see there is almost no difference between GlobInc and GlobHrz.

Look forward to hearing from you

Best regards,

Project_VC7_HourlyRes_1.pdf

[BOUBZIZI]

28 minutes ago, Emanuel Rodriguez said:

Dear PVsyst Team,

I have run some new simulations with the new 7.3.1 PVsyst version and found some problems with the Global incident Irradiation. The system has 6MW and one axis N-S trackers, in its simulations reports the Global Incident (GlobInc) value is very close to the Global Horizontal (GlobHrz) irradiation, I am getting a +1.2% * GlobHrz gain now but previously I got around +23.4%* GlobHrz that sound more sensible.

I did an advanced simulation to check the hourly values. However, I cannot see any significant difference of GlobInc from GlobHrz during morning and afternoon.

Do you know what could be happening? It is like the trackers are not moving or moving very slightly.

I have attached 2 images showing the difference between before and after version 7.3.1 and a PDF showing the hourly values of the after version 7.3.1 where you can see there is almost no difference between GlobInc and GlobHrz.

Look forward to hearing from you

Best regards,

Project_VC7_HourlyRes_1.pdf 824.45 kB · 1 download

 

[BOUBZIZI]

I am facing exactly the same problem. After PVSyst update, Global incident Irradiation decreases from 35% with PVSyst 7.2.21 versin to 14% with 7.3.1 version !!

 

Edited December 26, 2022 by BOUBZIZI

[Emanuel Rodriguez]

I wrote the PVSyst support by e-mail and got the following response: 

 

Quote

 

Hi,

 Yes sorry, there is an important bug in the version 7.3.1.

The tracking doesn’t work when you choose the “Irradiance Optimization” option in the “Orientation” part.

Please uncheck the “Irradiance optimization”, and everything will be fine.

 

 

NB: this option doesn’t have a big impact on the results. The gain is usually less than 1% , less when very sunny climate.

We will correct this for the next version 7.3.2 of course.