Jump to content

Performance Ratio for Bifacial modules


Recommended Posts


I'm designing a smaller ground based project and are currently investigating the option of bifacial vs monofacial modules. But what I don't understand is how the PR value is calculated for bifacial systems. I noticed that the PR is less for some of the bifacial systems compared to identical monofacial systems. 

When calculating the PR manually I use this equation: PR  = ("PV energy (AC) minus standby use") / ("Global Radiation at the Module" - "Reflection on the Module Interface") * module area * module efficiency )) 

But it doesn't match the PR when calculated manually for bifacial systems compared to what is presented in the report. How can I calculate the PR manually for Bifacial systems?


Hope to hear from you soon,

Link to comment
Share on other sites

  • 1 month later...

Hi Douglas,

please excuse the late answer. I just checked the calculation of the PR of bifacial modules in PV*SOL and couldn't find an error. Could you send the project where the manually calculated PR and the PR from PV*SOL differ? Just a small hint (but I don't think this leads to the problem): The brackets in your formula should be replaced like so:

PR  = ("PV energy (AC) minus standby use") / (("Global Radiation at the Module" - "Reflection on the Module Interface") * module area * module efficiency ) 

Kind regards,


Link to comment
Share on other sites

  • 1 year later...

Hi Douglas and Martin

I am trying to obtain the same PR value as it appears on the second page of the report


by calculating it with the data obtained by the minute simulation, I am usig the ecuation Martin wrote down but it is still not the same.


is not the reflection on the module interface included in Global Radiation at the module?.

*module area* module efficiency is the same that kWp, or the software change the module efficiency?.

I want to calculate the monthly PR, I have already seen the way to obtain it for each inverter. does this way include the soiling/ the reflection /the shading, how would be the ecuation of this PR.?


Kind regards




Link to comment
Share on other sites

Okay, I have found my mistake, the reason was I didnt subtrac the reflection on the module, I was adding it. because I thought that being a negative value you should add it.


I suppose that the reflection is not included in the PR therefore?.


Kind regards.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...