Design and Evaluation of a low-cost concentrator photovoltaic(PV)system using semi-diffuse structured aluminium reflectors

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Simfukwe, Joseph
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The production of energy from fossil fuels and nuclear materials has environmental drawbacks. These drawbacks include the creation of nuclear waste and the pollution associated with fossil fuels which lead to global warming and climate change. It is apparent that alternative and sustainable sources of energy must be found. A potential solution to this problem is solar electricity. Currently, solar panels are expensive and hence uneconomical for most consumers. The use of solar concentrators creates a potential for less expensive electricity because concentrators raise the amount of incident radiation over a relatively small area of the absorber. The reduction in cost is achieved by reducing the module area and by the use of low-cost reflectors. However, specular reflectors cause highly concentrated heating and form hot spots on the solar module cells. These hot spots are a result of uneven concentration of radiation. The overall effect is a reduced fill factor and reduced overall efficiency of the system. In this dissertation, we investigate an alternative solution to the problem of non-even illumination which uses locally available low-cost semi-diffuse reflectors with four different groove orientations scribed on them so as to scatter the radiation flux onto the module. The groove orientations were plain sheet (NG), horizontal (HG), vertical (VG), and criss-cross (CG). Our results show that locally purchased semi-diffuse aluminium structures can be used as booster reflectors with a performance comparable with that of commercial high specular reflectors. The results also show that the criss¬cross grooves (CG) gave the highest fill factor followed by the horizontal grooves (HG) and then the vertical grooves (VG). The plain sheet with no grooves (NG) had the smallest fill factor. The results also show that the drop in the fill factor from the reference value was about 3% for CG and HG, while the drops for vertical grooves
Concentrator photovoltic , Aluminuim structures