Modelling a PV system with bifacial vertical modules

Hi everyone, I have a problem regarding the simulation of the energy produced by a PV system with bifacial vertical modules. The system consists of 3 strings of 6 modules each. I would like to know the electrical output of the middle row of modules.

I have tried to model the system using 3d shade calculator considering only the surface of the middle row as ‘active’. The problem is that although I have specified in the ‘module’ tab that the panels are bifacial, by orienting the active surface to the west the system only produces energy in the afternoon, while by orienting it to the east the system only produces in the morning.

I also tried modelling the system without using 3d shade calculator (considering 3 strings of 6 modules) but I could not extrapolate the energy produced for the single row.

I hope someone can give me some tips.

Hello,

SAM does not report the output of individual rows.

If you use SAM's self-shading model with the "Thin film (linear)" option, the resulting shading loss should give you an indication of the reduction in plane-of-array irradiance on the middle row and last row because the self-shading model assumes the front row is not shaded. The loss is reported on the Results page as "POA front-side shading loss(%)." For bifcial modules the "POA rear-side self shaded loss (%)" is an estimate of the reduction of irradiance incident on the rear of the module.

You could use that information along with the "Annual DC energy (kWh/yr)" output to estimate the output of the middle row.

Best regards,
Paul.

Hi Paul,

Thank you very much for your kind response.

So I can make an estimate of the energy/power produced by the middle row based on the loss of POA irradiance caused by the shadows, but I cannot get it directly as a result from SAM. Am I right?

Best regards

Giovanni

Hi Giovanni,

Yes, that is correct.

Best regards,
Paul.

Thanks again for the clarification.

 Giovanni