Understanding Bifacial PV Modeling: Raytracing and View Factor Models

Conference · Wed Jan 29 04:00:00 EST 2020

OSTI ID:1597241

Ayala Pelaez, Silvana ^[1]; Deline, Christopher A ^[1]; Marion, William F ^[1]; Sekulic, William R ^[1]; Stein, Joshua S. ^[2]

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1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2. Sandia National Laboratories

As part of the PV Magazine Webinar 'View-factor vs. ray tracing - which bifacial modelling techniques should you use?,' the second part lead by NREL will explore the different rear-irradiance calculation software, which fall into two categories: view-factor and ray-tracing models. View factor models assume isotropic scattering of reflected rays, allowing for calculation of irradiance by integration. Due-diligence software such as PVSyst or SAM use the view-factor model. Ray-tracing models simulate multipath reflection and absorption of individual rays entering a scene. Raytracing software such as bifacial_radiance, which is the only available open-source toolkit, offers the possibility of reproducing complex scenes, including shading or finite-system edge effects. This can be useful to evaluate specific system geometries, shading and obstructions, areas of different albedo and electrical mismatch, all topics of interest to the prediction of bifacial performance. Model agreement for view factors and bifacial_radiance software is improving and has been shown to be between 2% (absolute) when compared with measured results.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1597241
• Report Number(s): NREL/PR-5K00-75628
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
bifacial PV
bifacial gain
bifacial_radiance
modeling
raytrace
rear irradiance
view factor