Your PV system is not suited for the bifacial 2D model computation

[Gyeongil Kwak]

Dear team,

I have updated to the latest version (ver. ) so that I am not sure if this occurred in the previous version.

I have multple projects and they were all designed based on bifacial module with almost identical "Fixed Tilted Plane" in a large area.

out of several projects, only two projects made this warninig:

"Your PV system is not suited for the bifacial 2D model computation, You should choose "unlimited sheds" in the "orientation" part, or define regular shed arrays in the 3D scene."

I could not find any clue in the manual and google search.

therefore, I expect your technical team can advise me in this matter.

Reproducing procedure"

1) create new project by selecting "New-grid connected project",

2) the put the project name, load meteo file from SolarGIS data.MET

3) Click tab "Orientation" and set up "Fixed Tilted Plane" and OK. all values at the moment is default.

4) Click tab "System", put "planned power" and selected PV module and inverter.

5) then Click "Bifacial system" and select "Use unlimited sheds 2D-model. Then the warninig message pop up.

Could you please advise me why this happened?

I am using same ".MET" data as they are not far away each other, and the whole procedures are exactly same for more than 10 projects.

but only Two projects made this warning and could not continued.

I look forward hearing for you in this matter.

Best regards

Gyeongil

[dtarin]

It will give you that error. First complete the system design portion of your model, exit system menu. Then go to the shadings menu and create a shading scene to remove the error.

[Gyeongil Kwak]

Thanks for your prompt response.

however, this does not help anything and it seems like my fault.

all set-up was already done as you advised me but I forgot to change in "Bifacial system" and I tried to change the 2nd options.

when I go "Bifacial system" and apply to "Use unlimited sheds 2D-model" this happended.

I did the same way for other projects (more than 10 projects) and it worked except two project.

could you please advise me?

Thanks in advance.

all set-up was done.

see the red-colored.

[Tsetsgee]

Dear team,

I have updated to the latest version (ver. ) so that I am not sure if this occurred in the previous version.

I have multple projects and they were all designed based on bifacial module with almost identical "Fixed Tilted Plane" in a large area.

out of several projects, only two projects made this warninig:

"Your PV system is not suited for the bifacial 2D model computation, You should choose "unlimited sheds" in the "orientation" part, or define regular shed arrays in the 3D scene."

I could not find any clue in the manual and google search.

therefore, I expect your technical team can advise me in this matter.

Reproducing procedure"

1) create new project by selecting "New-grid connected project",

2) the put the project name, load meteo file from SolarGIS data.MET

3) Click tab "Orientation" and set up "Fixed Tilted Plane" and OK. all values at the moment is default.

4) Click tab "System", put "planned power" and selected PV module and inverter.

5) then Click "Bifacial system" and select "Use unlimited sheds 2D-model. Then the warninig message pop up.

Could you please advise me why this happened?

I am using same ".MET" data as they are not far away each other, and the whole procedures are exactly same for more than 10 projects.

but only Two projects made this warning and could not continued.

I look forward hearing for you in this matter.

Best regards

Gyeongil

Hello!

 

Gyeongil Kwak, did you solve why this warning pop up?

I have occurred this problem too.

[dtarin]

Thanks for your prompt response.

however, this does not help anything and it seems like my fault.

all set-up was already done as you advised me but I forgot to change in "Bifacial system" and I tried to change the 2nd options.

when I go "Bifacial system" and apply to "Use unlimited sheds 2D-model" this happended.

I did the same way for other projects (more than 10 projects) and it worked except two project.

could you please advise me?

Thanks in advance.

 

Is your pitch uniform in the shade scene?

[shifatmaid]

I'm having a similiar problem as the thread starter, however my problem comes from the bifacial system definition not reacting to the settings in my 3d scene.

I'm in investigating how bifacial solar park can be optimized via varying pitch. To do so I have created 20 different shading scenes for bifacial modules where the only difference is the pitch, ranging from 11 m to 6 m in steps of 0.3 (giving us 20 shading scenes). But as soon as I import the shading scene for pitch 10.4 and 10.1 I get the same error as mentioned above, followed by the following text:

"Your PV system is not suited for the bifacial 2d model computation: the pitch between tables is not sufficiently homogenous. You should define regular sheds in the 3d scene"

The other pitches seem to be fine, for now I'm only getting this error for pitch 10.4 and 10.1. So i double-checked the shading scenes and the pitch is the same everywhere. But when i checked the bifacial system definition the pitch is not changed accordingly for pitch 10.1 and 10.4, but does so for the other pitches which is strange to me. And when I try to change the pitch manually it goes back to its old value after saving. Has anyone else encountered the same problem, and how can this easily be solved if possible?

[jbennett]

Similar problem for me. I am trying to model carport canopies with bifacial modules. 3 degree tilt. Some projects have only one azimuth, others have multiple azimuths.

However, none of these arrays would fit the description of a "shed" in PVsyst. And defining them in the 3D scene doesn't seem to make a difference--PVsyst says the systems are not suited for the model computation.

Can anyone confirm that modeling bifacial systems, can ONLY happen with sheds? And if yes, any appropriate work-arounds to get by this limitation (e.g. split each array into two subarrays of two sheds each, and make the pitch very large between them?

Thanks,

John

[gonecrawfishin]

correction, I updated to v7.2.4 and I sometimes no longer get this error. I sometimes do though, and am not sure what I'm doing differently. Is there a certain order to entering data that needs to be followed?

----------------------

Has there been any resolution on this topic? I also get that error, and am not yet finding answers in the forum or help.

[tejjoshii]

Similar problem for me. I am trying to model carport canopies with bifacial modules. 3 degree tilt. Some projects have only one azimuth, others have multiple azimuths.

However, none of these arrays would fit the description of a "shed" in PVsyst. And defining them in the 3D scene doesn't seem to make a difference--PVsyst says the systems are not suited for the model computation.

Can anyone confirm that modeling bifacial systems, can ONLY happen with sheds? And if yes, any appropriate work-arounds to get by this limitation (e.g. split each array into two subarrays of two sheds each, and make the pitch very large between them?

Thanks,

John

 

I have the same issue. There is no option for defining bifacial system with multiple orientations. If we choose unlimited sheds then we can't have multiple azimuth. And if we define multiple azimuth in shading scene then it selects "Several orientations" and we get the "not suited for bifacial" error.

[dtarin]

Pitch and tilt need to be uniform for bifacial. Split the different orientations into different variants and combine in excel with the 8760.

[unilhexio]

Hi!

I could see what you're telling here. Sometimes I get the "Error" message when use different pitches in a simulations, and sometimes I didn't and I could do the simulation as usual.

The way to perform the simulation is to adjust the advanced parameter "Pitch RMS limit for bifacial 2D models". It is 0.10 m by default. I don't know the impact of increasing this number, but it allows the simulations to be done.

[Nikoloz]

Hello there

Does anybody solve this problem ?? I have the same issue --- For example I have one project 498kWp with bifacial modules...when a make them in "Near shading"  and number of modules in length 1 and in height X modules on each table with pitch  5m. it is ok  no errors acquire ... but when I make  2 modules in length and X modules in height with pitch 10m the  same error appears on screen...I think it is PVsyst's problem some bug mabe

[Michele Oliosi]

Please check the following help page: https://www.pvsyst.com/help/bifacial-conditions.htm

This is not a bug but the current limitation of the bifacial model. It is possible to extend the modeling to situations with an inhomogeneous pitch, via the advanced parameters described in the help page (increase the threshold pitch RMS deviation value). The simulation will run, however the results may be somewhat inaccurate for the backside irradiance.

[Michele Oliosi]

On 11/5/2021 at 1:02 PM, unilhexio said:

Hi!

I could see what you're telling here. Sometimes I get the "Error" message when use different pitches in a simulations, and sometimes I didn't and I could do the simulation as usual.

The way to perform the simulation is to adjust the advanced parameter "Pitch RMS limit for bifacial 2D models". It is 0.10 m by default. I don't know the impact of increasing this number, but it allows the simulations to be done.

There is no impact of increasing this number. It simply allows simulating situations which are not well modeled by the bifacial backside irradiance model.

[drokxytext]

I'm having a similiar problem as the thread starter, however my problem comes from the bifacial system definition not reacting to the settings in my 3d scene.

[Michele Oliosi]

On 1/19/2024 at 3:03 PM, drokxytext said:

not reacting to the settings in my 3d scene

which settings in particular ?

[jameswookyz]

Similar problem for me. I am trying to model carport canopies with bifacial modules. 3 degree tilt. Some projects have only one azimuth, others have multiple azimuths. 

[Michele Oliosi]

As mentioned above, in PVsyst v7 it is not possible to run multiple orientations with the bifacial model.
You should either make a variant where you approximate all orientations with the average one, or split your differing orientations into separate variants.