Comparing the performances of different cooling strategies to increase photovoltaic electric performance in different meteorological conditions

Photovoltaic represents the most consolidated technology for the production of clean and renewable energy. Even though several new type of cells have been proposed, the first generation crystalline silicon is still the most used worldwide due to the reliability in long-term efficiency and yields. A main limitation is the strong dependency of the electric efficiency on the operative temperature, that markedly decreases with high solar radiation. Cooling systems can be an efficient solution, helping to contain the temperature rise. In this paper, the long-term performances of three different cooling technologies, based on spray cooling and forced ventilation, acting on the back surface of photovoltaic modules were assessed. In sunny days the cooling systems were able to reduce the back temperature by up to 26.4 °C. The analysis also verified the uniformity of temperature distribution. The good performances of the spray cooling system were sanctioned by the efficiency that in August reached 14.3% compared to the 12.7% of the reference module. The monthly increment in electric energy for the most performant system ranged from 1.4% in December to 8.6% in June. For the whole analysed period, the greatest increment of 6.1% in energy yield was determined.