Impact of the atmospheric conditions to the bandgap engineering of multi-junction cells for optimization of the annual energy yield of CPV

The spectrum influence on the CPV multi-junction cell is not only responsible for the air mass but significantly influenced by the fluctuation of the atmospheric parameters. The Monte Carlo simulation assuming the best and worst conditions of the distribution of parameters was examined to the CPV multi-junction cells. It was shown both aerosol density and water precipitation affects to the optimum bandgap design. The optimum bandgap set in the area of the worst aerosol density was significantly different from those of the best area. Even though the bandgap was designed maximizing the annual energy yield in a set of annual data, the fluctuation of the atmospheric parameters affects the annually mean efficiency to ±5 % (best area) and ± 9 % (worst area). Considering this considerable influence on the annual energy yield of the CPV multi-junction cell, with junctions connected in series, the best number of the junctions was 4 and more than five junctions were not better for the annual energy yield.