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 Post subject: Bifacial Performance RatioPostPosted: Fri Feb 21, 2020 5:41 pm

Joined: Tue Feb 11, 2020 3:51 pm
Posts: 1
How does PVsyst calculate its performance ratio with Bifacial modules?
Is the Irradiance just the front side that it uses for its performance ratio calculation?
Or does it take into account the rear side Irradiance?
I can't seem to find anything useful on this.

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 Post subject: Re: Bifacial Performance RatioPostPosted: Sun Mar 22, 2020 2:08 pm

Joined: Tue Mar 27, 2018 6:23 am
Posts: 9
As I understand, PVSyst 6.86 uses only front side irradiation for calculating PR.
This is evident when rear side irradiation is significant which results in >100% PR.
Try running bifacial simulation with E-W configuration.
Hope it helps.

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 Post subject: Re: Bifacial Performance RatioPostPosted: Wed Apr 08, 2020 5:32 am

Joined: Sat May 05, 2018 9:57 pm
Posts: 5
Quote:
How does PVsyst calculate its performance ratio with Bifacial modules?
Is the Irradiance just the front side that it uses for its performance ratio calculation?
Or does it take into account the rear side Irradiance?
I can't seem to find anything useful on this.
Hello

No, it doesn't take the rear side irradiance into accounu, until know the biracial performance ratio is calculated as the mono-facial.

"PR for bifacial systems

The definition of the performance ratio should be something like a standard, defined by an official instance, and accepted by everybody.
Now I have not yet seen any reference which would define a performance ratio for bi-facial systems. Therefore PVsyst cannot propose any specific value in the present time.
The value provided presently with the PVsyst results uses the definition of the Monofacial systems, so that the bi-facial gain comes as an increase of this ratio.

NB: The main objective of the PR is to find an indicator for comparing real and simulated data, therefore which may easily be evaluated using simple (and "primary") measured data.
However neither the rear side irradiance, nor the part of the bifacial gain is available in usual measurements."

Source: viewtopic.php?t=31

Best Regards,
Nedal Nassar

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 Post subject: Re: Bifacial Performance RatioPostPosted: Fri Oct 15, 2021 9:25 pm

Joined: Fri Oct 15, 2021 9:22 pm
Posts: 1
Location: Brazil
Quote:
Quote:
How does PVsyst calculate its performance ratio with Bifacial modules?
Is the Irradiance just the front side that it uses for its performance ratio calculation?
Or does it take into account the rear side Irradiance?
I can't seem to find anything useful on this.
Hello

No, it doesn't take the rear side irradiance into accounu, until know the biracial performance ratio is calculated as the mono-facial.

"PR for bifacial systems

The definition of the performance ratio should be something like a standard, defined by an official instance, and accepted by everybody.
Now I have not yet seen any reference which would define a performance ratio for bi-facial systems. Therefore PVsyst cannot propose any specific value in the present time.
The value provided presently with the PVsyst results uses the definition of the Monofacial systems, so that the bi-facial gain comes as an increase of this ratio.

NB: The main objective of the PR is to find an indicator for comparing real and simulated data, therefore which may easily be evaluated using simple (and "primary") measured data.
However neither the rear side irradiance, nor the part of the bifacial gain is available in usual measurements."

Source: viewtopic.php?t=31

Best Regards,
Nedal Nassar
And what about now... IEC 61724-1:2021 is available!

_________________
Ben Possatto
Solar Performance Engineer

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 Post subject: Re: Bifacial Performance RatioPostPosted: Mon Oct 18, 2021 8:00 pm

Joined: Tue Oct 18, 2016 3:31 am
Posts: 448
Manually calculate PR and include the rear-side irradiance with the front-side irradiance.

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