Optical and electrical behavior of an underwater linear-focusing solar concentrating photovoltaic

Limited attention has been devoted to the harvesting of underwater solar energy for underwater or near-water energy use scenarios. This paper proposes an underwater linear-focusing solar concentrating photovoltaic, which holds the potential to energize subaquatic devices or cater to the electricity needs of islands and coastal regions lacking adequate electricity and terrestrial resources. It mainly encompasses a novel designed underwater solar concentrator with a satisfactory light interception angle and the photovoltaic module. To determine the concentrator's optical performance, optical simulations are conducted. The results illustrate that within the incident angle of 20°, the concentrator can 100% intercept the incident light and has an energy concentration ratio greater than 2.37. Besides, a theoretical model and an experimental setup with solar cells' areas of 0.006 m² are developed to study its electrical performance. Its electrical efficiency is found to be 12.60% at 0 cm depth and 6.56% at 100 cm depth. Additionally, the greater the water turbidity, the greater the decrease in its electrical efficiency as the water depth increases. At the water depth of 100 cm, the electrical efficiency decreases by 84.27% as the water turbidity increases from 0 NTU to 15 NTU. This work demonstrates the practicality and validity of the underwater solar concentrating photovoltaic technology.