A novel evaporative cooling technique for uniform thermal regulation and improved electrical efficiency of photovoltaic panels
摘要
Increases in photovoltaic panel operating temperature reduce electrical efficiency; therefore, the development of an effective and low-cost cooling approach that ensures uniform heat removal is essential. This study presents a novel rear-surface evaporative cooling system based on hemp rope porous material for photovoltaic panels. The proposed cooling system was designed to enhance thermal regulation while ensuring a practical configuration and low water consumption. The cooling system was experimentally evaluated under hot and arid climatic conditions using three water-spraying intervals (30, 60, and 120 min). For the reference (uncooled) PV panel, the average surface temperature, electrical efficiency, and power output were 66.5 °C, 16.5%, and 15.1 W, respectively. The proposed cooling system reduced the average panel temperature by 16.58 °C, 17.95 °C, and 13.47 °C for the 30-min, 60-min, and 120-min spraying intervals, respectively, compared with the reference panel. These reductions resulted in corresponding increases in average electrical efficiency of 7.92%, 8.52%, and 5.97%, respectively, relative to the reference panel. An economic analysis indicated that the estimated payback periods were 3.18, 2.91, and 4.58 years, while the levelized cost of electricity values were 0.0223, 0.0217, and 0.0236 USD kWh−1, respectively. In addition, the cooling system was projected to achieve additional CO2 emission reductions of 31.96, 34.73, and 23.73 kg, respectively, compared with the reference PV panel over a 25-year lifetime. Overall, the proposed cooling technique offers a practical, cost-effective, and efficient approach for photovoltaic applications in hot and arid environments.
Graphical abstract