A model was developed to predict the amount of solar radiation incident on a solar collector's surface. A Python based model tracked the sun's location and determined how much energy would strike a surface at any orientation. As a demonstration several fixed tilt angles and a tracking case were simulated for Schenectady, NY. Results followed the expected trends. Future goals for the model are to confirm its results numerically with experimental data and use it to determine optimal arrangements for bifacial solar collectors.
Bifacial solar is a promising technology in solar energy that has the potential to increase the amount of power a single solar panel can generate by allowing light to be collected on both sides of the module. Understanding how best to use these bifacial solar collectors is non-trivial as many factors go into the mounting geometry and these tend to be interrelated, requiring a case-by-case analysis. Reflectors can be used to shine more light onto the back of panels increasing their power output, making the geometry more complicated. The development of a model that can take the characteristics of a certain mounting location and determine the best bifacial mounting arrangement would therefore be helpful. This study presents a model for determining the incident energy on both sides of a bifacial collector. The model is able to analyze the use of reflectors and of spacing of rows in solar farms. These capabilities were demonstrated by simulating a bifacial panel mounted vertically with a vertical reflector behind it. Some experimental verification of the shading model has been performed with promising results. Otherwise results follow expected qualitative trends, but further experimental verification is in order. The hope is that this model can be applied to optimizing bifacial panel mountings in future studies.
“ … late 2020 through 2021, Matthew Rueter developed a computational model to accurately … l_ver.pdf . [Accessed: 26-Oct-2021]. [3] Rueter, M. “ Modeling of Incident Solar Energy on Bifacial … ”
Abstract
Bifacial photovoltaics are an expanding sector of solar electricity production, collecting solar energy on the front, back, and sides of the module. This increases the efficiency by around 10% to 30% over a typical mono facial cell, which only collects sunlight on the front. However, the performance of bifacial PV arrays depends on a variety of factors, including temperature, shadows, solar insolation, and set-up geometry. The geometry is affected by the tilt angle, the azimuth angle, the height from the ground to the panel, and the reflectance from the ground surface. The addition of a reflector, usually white in color to reflect sunlight, further complicates a PV configuration. When a reflector is added to face the backside of a collector, the set-up can then be enhanced to increase the bifacial gain, or the ratio of rear side energy to the front side. This paper will use a numerical model through the Python coding language to determine the incident energy on both sides of a bifacial collector. The computational model could then be verified through data gathered from an experimental setup using smaller PV cells to simulate the backside of a bifacial collector. Then by combining both the experimental and computational data, an indoor, sized-down model could be used during the winter months. The computational model was helpful in verifying trends found through experimental data. A 1 m reflector-collector distance in the outdoor model to found to significantly increase the energy collected by 20%. Nonuniformity between the rows was observed as the reflector was moved closer, due to a lower view factor. There is an optimal distance where BG peaks, then the BG plateaus when moved further. Because a large variety of factors contribute to the set-up of PV arrays, many tests need to be conducted, and the optimal arrangement is difficult to decipher.
