Bifacial and Monofacial Panels in a same system

[Omama Zaheen]

On a 660kW site, I have used both Bifacial and monofacial solar panels. 44 strings are of bifacial panels and 1 string in a separate MPPT has all monofacial panels. While running Simulation PV syst give the error that "When Defining a bifacial system, you should define a bifacial PV module in each sub-array"
Why is it giving such error? I have used the monofacial panels in a different MPPT

[Michele Oliosi]

Sorry, at the moment it is not possible to have both monofacial and bifacial modules in the same system in PVsyst. This will be addressed in the future.

[laurahin]

What if we edit the PAN file of the monofacial module to indicate that it's bifacial with a bifaciality factor of 0?

[dtarin]

On 12/11/2023 at 4:30 PM, laurahin said:

What if we edit the PAN file of the monofacial module to indicate that it's bifacial with a bifaciality factor of 0?

Someone reported a difference on the forums . I would run a test, find the delta, then apply in MQF or post-process. 

 

[André Mermoud]

You can define a PV module by activating the Bi-facial feature, and specify a bifacial factor = 0.

There is indeed a difference when simulating with the bifacial model (and Bifacial factor = 0) and without.

The bifacial calculation  includes a contribution for the reflexion of the near ground in front of the PV modules (named "Ground reflexion on front side" on the loss diagram). This uses the whole "mechanics" of the 2D bifacial model.

This contribution cannot be calculated in a simple way.  It depends on several parameters like the ground albedo, the height above the ground, the pitch, etc.  It is neglected in the usual monofacial simulations.

 

 

[Michele Oliosi]

I should also add, that when you combine sub-arrays with different bifaciality factors, we use a weighted average (based on nominal DC power) to compute an average “bifaciality factor” for the whole system.