Simulation on water photovoltaic heat exchange mechanism and influence on water quality, a case on the middle route of South-to-North Water Diversion project

Water photovoltaic (WPV) power stations have developed rapidly in recent years around the world. However, the thermal performance, power generation characteristics and the influence on water temperature and water quality of WPV power station need to be further studied. At present, there is no systematic and complete numerical method that can simulate the impact of solar panel on water environment. In this paper, a joint calculation method of WPV heat exchange model and 1-D hydrodynamic and water quality model is proposed. Taking Hebei section of the middle route of the South-to-North Water Diversion project as an example, the solar panel temperature, electrical efficiency, water temperature and water quality changes are analyzed. The results show that, compared with the static water condition, the solar panel temperature and air temperature below the panel decrease under flowing water condition. And the photoelectric efficiency is improved. After covering the WPV, the air temperature below the panel is significantly affected by the solar panel temperature. When moving from south to north along the middle route of the South-to-North Water Diversion project, the photoelectric conversion efficiency of WPV gradually increases, but module output power per square meter drops by 1.75 W/m². The short-wave radiation flux reduction factor of WPV should be less than 20 % for ensuring the stability of water quality and the large discharge will weaken the short-wave radiation flux reduction influences on water quality.