The Effect of Tilting a PV Array by Monthly or Seasonal Optimal Tilt Angles on Energy Yield of a Solar PV System

The energy yield from a photovoltaic (PV) array is highly dependent on the array angle of inclination with respect to the horizontal plane. For a fixed mounted PV array, the yearly optimal tilt angle is the angle that maximizes the solar radiation falling on the array surface throughout the year and thereby maximizes the electrical energy production. This paper discusses the impact on the energy yield when tilting the PV array by monthly or seasonal optimal tilt angles rather than by the yearly optimal tilt angle. The gain percentage of energy yield from a PV array was calculated when the array was tilted by the monthly optimal tilt angles and also when the array was tilted by the seasonal optimal tilt angles. The geographic location of the University College of Science and Technology located in Gaza Strip – Palestine was selected in this study. Photovoltaic Geographical Information System (PVGIS) software was used to produce the results. The results showed that the produced energy increased by 5.82% and 4.77% using monthly and seasonal optimal tilt angles respectively. In order to confirm the results, System Advisor Model (SAM) software developed by the National Renewable Energy Laboratory (NREL) was used. The results obtained from SAM software were close to those obtained from PVGIS software tool.