Abstract
The performance of photovoltaic (PV) modules is significantly impacted by elevated operating temperatures, which lead to reduced efficiency and lower energy output. As the global demand for renewable energy continues to grow, improving the efficiency of PV systems, particularly in high-temperature environments, is crucial for optimizing solar energy production. This study explores the effectiveness of a hybrid cooling technique that integrates evaporative cooling (EC) with forced air convection (induced by a small 5.3-watt DC fan) to reduce the temperature and enhance the efficiency of a 30-watt monocrystalline PV module (dimensions: 450 mm x 510 mm).
The results indicate that hybrid cooling effectively improves the thermal management of the PV module, leading to lower operating temperatures and enhanced efficiency compared to the uncooled (reference) module. On test day #1, no significant cooling was observed due to the 75-mm thick cellulose pad, which restricted airflow and limited natural convection. However, by reducing the pad thickness to 25 mm (13 of the original thickness) on test days #2 and #3, the evaporatively cooled (EC) module achieved a maximum temperature reduction of 17.83°C and a maximum 10.2% increase in efficiency over the uncooled module.
For test days #4 and #5, the 25-mm thick pad was used in combination with forced air convection induced by a small 5.3-watt DC fan, creating a hybrid cooling system. This setup allowed for a direct comparison of the effectiveness of the hybrid cooling system against the evaporative cooling (EC) method under the same environmental conditions (wind speed, solar irradiance, relative humidity, and ambient temperatures). On test day #4, the EC-hybrid system achieved a maximum temperature reduction of 5.3°C and a maximum efficiency enhancement of 11.25%, compared to 3.6°C and 10.2%, respectively, for the EC-only module. On test day #5, the results improved further, with the hybrid-cooled module attaining a maximum temperature reduction of 14.3°C, compared to 7.9°C for the EC module. In terms of efficiency, the hybrid model achieved a maximum efficiency enhancement of 10.77%, compared to only 4.01% for the EC module.
These findings highlight the effectiveness of the hybrid cooling system in improving both thermal management and efficiency, surpassing the performance of the evaporative cooling method alone. The hybrid system used in this study also offers several key advantages, including minimal water usage, silent fan operation, environmental sustainability, and cost-effectiveness.
This research provides valuable insights into optimizing cooling performance for photovoltaic (PV) systems, with future studies exploring different cellulose pad thicknesses and types to further enhance performance in outdoor conditions.