Different Global Inc. plane with same meteo data

[Vinh Thinh]

Hi everyone,

for two neighboring projects having the same meteo data as well as same tracker configuration in terms of width and length of the tables, I get very different specific production in the order of 120 kWh/kWp.

Looking at the loss diagrams of the two simulations, I noticed that the difference mainly relies upon the imported 3D scene (.pvc), as the one with lower production features a more undulating topography. Therefore, as far as I understood, it is reasonable to have higher losses such as Near shadings and shading losses according to strings for the project with challenging terrain. However, I was also noticing that the parameter Global Incindent in collec. plane is quite different, with the project with more challenging topography having a gain 6% less than the other. Such divergence can be justified by the different 3D scene?

Considering all these aspects and seeing the below loss diagrams, do you think that for two close projects, such deviation in production can be linked to the 3D scene, meaning the underneath topography?

I hope you can help me with those questions, and I'm available for further discussions. 

Best regards.

 

[Michele Oliosi]

Hi, can you share the pages with "General parameters" ?

To be able to say for sure we would need to know the typology of your array of trackers / tables.

I suspect you have the irradiance optimization on ? If so, the change may be due to the shading evaluation being overall more precise.

If you would like for us to check in more details you can also send your project over at support@pvsyst.com

[Vinh Thinh]

Hi Michele,

 

thank you for your answer. Below you can find the comparison between the "General parameters" pages for the two projects.

As for the question about irradiance optimization, I just checked it and it has not been activated in neither of the two simulations.

I will also share my projects with you through the mail you have mentioned.

Looking forward to having a clearer view on this matter 🙂

 

[Michele Oliosi]

The average tilt angle is quite different. this means that the trackers are arranged differently ?
If so the tracking motion will also be different. If the plane orientation changes, then transposition gains will also change.

[Vinh Thinh]

Thank you for your answer. So from your reply, I do understand that the topography being used to simulate the two variants is affecting the average tilt and therefore the transposition gain in a way that it justifies the difference of 120 kWh/kWp in the energy production.

 

[Michele Oliosi]

Yes that's it !