Optimisation of Tilt Angle for Different Photovoltaic Panels Under the Prevailing Environmental Conditions in Melbourne (Australia)

The optimum tilt angle of a photovoltaic (PV) system was found by varying it between 9° and 49° at 5–10° increment over a period of three months and recording the output of the five different technologies installed. These technologies included mono-crystalline, poly-crystalline, HIT, thin film CdS/CdTe and thin film CIS modules. The yield and efficiency of these modules were determined experimentally and also by the SAM (Solar Advisor Model) computer software; these results correlated with each other to within ±15% with R² = 0.72 (R = 0.85). This correlation improved when a longer period of time was considered in the simulations. An optimisation study found that the optimum fixed tilt angle was 31.8° for all technologies except thin film CIS modules for which the optimum angle was 27.9°. Furthermore, the yield of another PV system was recorded from April 2010 to July 2011 and compared with its prediction by the SAM simulations. It was found that there was an excellent agreement between the two sets of data. An optimisation study using SAM found that the increase in annual predicted energy generation as a result of changing the tilt of the panels from the current fixed value of 25° to the optimised tilt angle of 31.8° was only 1.1%. A similar optimisation study for a third PV system found that the increase in energy generation predicted after changing the tilt angle from 10°-12° to their optimum tilt angle was 1.9%. The optimum tilt angles found in this study were in good agreement with previous studies reported in the literature.