Seasonal variation of thermal and electrical characteristics of 684 kW DC solar photovoltaic system in thailand: Statistical and performance evaluation

• Seasonal electrical and thermal characteristics are studied. • Pearson Correlation estimates the thermal impact over different seasons. • During summer, the inverter power conversion loss is high. • The temperature correction factor effectively demonstrates efficiency deviation. • Higher PR is attained in winter. In recent years, solar PV systems have faced challenges in identifying and understanding losses, which are often limited by descriptive performance analysis. In this study, the thermal and electrical characteristics of a 684 kWp solar PV system are investigated under tropical climatic conditions in Thailand. A statistical analysis was performed using a box plot and the Pearson correlation method. Following that, a temperature sensitivity analysis was conducted using a non-descriptive platform to evaluate the Performance Ratio (PR) and efficiency across the four seasonal categories. It was found that in 2016, the recorded summer solar irradiance was 489 W/m², 753.5 W/m², and 918 W/m² for Quartiles 1, 2, and 3, respectively, indicating that Thailand has a rich solar energy potential. Due to tropical climatic conditions, solar irradiance has a significant impact on increasing the ambient temperature, which in turn raises the operating temperature of the PV module. During the winter periods, solar irradiance showed a strong positive correlation with current and power generation, with a correlation coefficient of 0.99. However, the monsoon period had a slight variation, with a range of 0.948. Similarly, the monsoon period experienced higher inverter power conversion loss due to frequent clouds. The highest and lowest power generation periods occurred during the presummer and monsoon seasons, with ranges of 3415.14 kWh and 1574.98 kWh, respectively. The Temperature Correction Factor (TCF) indicates that the impact of thermal effects on the solar farm was high. A TCF baseline of 40°C shows a greater efficiency enhancement; however, it indicates an adverse effect on the Performance Ratio (PR). The highest efficiency of 17.43 % was achieved during the summer period, due to the lower temperature differences between the modified baseline operating temperature and the PV module. The corresponding PR was 0.71, comparatively 0.10 lower than TCF at 10°C. Furthermore, it is recommended to cool the PV module operating temperature by approximately 10 °C to enhance the efficiency of the solar farm.