Photovoltaic System Performance Enhancement With Nontracking Planar Concentrators: Experimental Results and Bidirectional Reflectance Function (BDRF)-Based Modeling

Nontracking planar concentrators are a low-cost method of increasing the performance of traditional solar photovoltaic (PV) systems. This paper presents new methodologies for properly modeling this type of system using a bidirectional reflectance function for nonideal surfaces rather than traditional geometric optics. This methodology allows for the evaluation and optimization of specular and nonspecular reflectors in planar concentration systems. In addition, an outdoor system has been shown to improve energy yield by 45% for a traditional flat glass module and by 40% for a prismatic glass crystalline silicon module when compared with a control module at the same orientation. When compared with a control module set at the optimal tilt angle for this region, the energy improvement is 18% for both systems. Simulations show that a maximum increase of 30% is achievable for an optimized system located in Kingston, ON, Canada, using a reflector with specular reflection and an integrated hemispherical reflectance of 80%. This validated model can be used to optimize reflector topology to identify the potential for increased energy harvest from both existing PV and new-build PV assets.