Performance evaluation of a conventional and a double-glass cover solar stills

The operating performance of a double-glass cover solar still with 10 mm spacing (i.e., solar still with cooling water flowing between a double-glass cover) was evaluated experimentally under the climatic conditions of Muscat, Oman. The base area of the still was 1 m2 (i.e., 1 m length by 1 m width) and the cover of the still was made an angle of 23.4 degree with the horizontal optimized for 23.37 N latitude of Muscat. For comparison purposes, a conventional (single-glass cover) solar still with the same dimension was also designed and fabricated. The performances of the two stills were experimentally investigated under identical operational and weather conditions. The experimental study was conducted on some of the factors that affect the productivity of the solar stills. This included the water depth in the basin and the effect of the insulator. The tests were also performed using de-ionized water and sea water as feed. The productivities of the two stills and the temperatures of the water and the glass covers were determined. The quality of the water produced was tested. It was found that more yield of fresh water was obtained in case of a double-glass cover solar still as compared to the single-glass solar still. This is due to higher temperature difference between the water and inner glass cover. The chapter has also revealed that the water depth is inversely proportional to the productivity of the stills. Hence, the daily production of the two stills was increased by reducing the depth of the water in the basin.