A study of cover slope effect on productivity of solar still under Tunisian winter and summer conditions

The Tunisian country will suffer from the scarcity of clean and healthy drinking water in the near future. Solar still-based water distillation is one of the simplest cheap technologies that may solve this problem. The present study addresses this problem through experimentally and numerically investigating the feasibility of water desalination with a passive solar still in actual Tunisia Sfax central region climate conditions as well as the glass cover angle effect on the productivity of the solar still. The study was conducted for 2 days so that 1 day is in the summer and another day in the winter for comparison purpose. The flow solution was obtained with the Fluent solver Eulerian multiphase model coupled to a developed C +  + mass transfer code based on the Dunkle model. The considered glass cover angles are 5°, 10°, 20°, 30°, 45°, and 60°. The deviation between the numerical results and test data does not exceed 15% which ensures the validity of the calculation method. Both experimental and numerical results showed that the solar still productivity in summer is by far better than that in winter. The optimal glass cover angle was found to be of 20° in both summer and winter seasons. The maximum daily water yield is of 535.64 ml on January 15, 2021 and 3083.11 ml on June 15, 2021. The results proved that the solar still can be an efficient device for solar desalination in Tunisia central region.