A concentrating light multistage rising film solar distiller with a central cooling structure

This paper presents a concentrating light multistage rising film solar distiller with a central cooling structure (RFSD). The RFSD mainly consists of the semicircular concentrator, a rising film device and a central cooling structure. The structure design of the semicircular concentrator is introduced in this paper. The relationship between the light receptivity of the semicircular concentrator and the solar incident angle was obtained by optical simulation. The mathematical model of RFSD was established, and the process of heat and mass transfer in RFSD was analyzed theoretically. Based on theoretical analysis, an experimental device was built. Furthermore, the device's water yield performance and energy utilization efficiency were tested under actual weather conditions. The experimental results show that when the average daily solar irradiance is 606.0 W/m², the freshwater yielded by the device can reach 4450 g/m², and the average daily efficiency is 81.6%. The comparison between the theoretical and experimental results shows that the theoretical model in this paper can well predict the device's operating parameters. The deviation of the theoretical operating temperature from the experimental value is within 2.3 °C, and the deviation of the daily water yield efficiency is on a scale of 14.1% to 24.8%.