Productivity enhancement of a double slope solar still coupled with a solar system

Water shortage is rising to become a global challenge due to the variations in climate change and population increment. Converting the seawater to potable water using the desalination technology is among the existing options highlighted by researchers. However, these processes are expensive and require much energy to operate. The solar desalination technology was reported as highly adequate since it utilizes the natural sunlight and the simple concepts of evaporation and condensation to produce the drinking water. The main challenge to date is the low productivity of the technology, which must be adequately improved in order to enhance productivity and optimize performance. In this study, the productivity and efficiency of conventional double slope solar still were assessed using a solar system. Two solar still models (active and passive) were fabricated with the same evaporation and condensation areas. The troughs were made of stainless steel with dimensions of 50x32 x5 cm. In turn, while the cover was made of glass with dimensions of 48x60x0.3 cm and the inclination angle was 60o. In addition, the solar system consisted of two solar panels with 50 W capacity each, one battery of 100 Ah-12 V, a charging controller of 30 A, and a single immersed DC water heater of 50 W-12 V capacity. Both models were tested simultaneously for two sunny days, 24 hours each. The results showed that the water productivity of the active solar still was 55% higher than that of the passive solar still. On 15th July, the total amounts of solar still productivity were 7.85 L/m2/d and 19.3 L/m2/d for active and passive stills, respectively. This is due to the existence of the heating element in the active still which allowed it to produce water for 24 hours continuously. Moreover, the trough temperature was found to be the highest for both models, because it was made from steel. Finally, the produced water in both cases was found to be directly proportional to such parameters as solar radiation intensity and ambient temperature.