MODIFIED SINGLE SLOPE SOLAR STILL WITH EXTERNAL REFLECTORS

In this work, a single slope still with a single basin that has dimensions of 100 cm 100 cm and is composed of 2 mm thick galvanized iron-sheet, is designed with external reflectors to develop and maximize the system's efficiency. This modification allows to increase the system's heat inside the solar still that contains the desalinated water through a glass cover. The conventional design is compared with the modified design during daytime. The temperatures of the inner glass, outer glass, water in the basin, and the outside temperature were recorded every half an hour. The basin and reflectors were maintained as the same size. During testing, four external reflectors were used from the still's four sides, and their effects on productivity were examined. The temperature of the distilled water, the inner and outer glass covers, the water in the basin, the stills with and without reflectors, and the surrounding temperature, pressure, wind speed, and direction were all monitored every half hour. Results of the test for a typical summer day showed that the water temperature increases until it reaches its peak in the afternoon because more solar energy is absorbed than is lost to the atmosphere. Around 2 pm, the amount of solar energy lost starts to outweigh the amount of solar radiation absorbed, which results in a decrease in water temperature due to glass has a lower temperature than water, it can condense vapor. Early in the day, when the water absorbs less energy, there is less productivity since the temperature differential between the water in the glass and the air is smaller. The maximum peak solar radiation intensity increased by roughly 17%. Also, glass, water and absorber temperatures were enhanced. Hourly and cumulative water productivities were improved by 40% and 50% respectively.