In this research, a rotating Solar still that uses external bottom reflectors was experimentally investigated. The Solar still and reflectors have the capability to shift their angle with respect to the south and the reflectors have the capability to shift their angle with respect to the horizon. The experiment has been performed in both fixed and rotating states. For the fixed state the Solar still was placed toward south and the reflectors were set in such a way to reflect sun rays on the bottom surface of the basin at Solar noon. For rotating state, the Solar still and reflectors were set manually every half an hour in such a way to reflect sun rays on the bottom surface of the basin and the system was directed toward the sun all the time. The experiments were performed from November to December for 27 days. Sunny days results indicated that on average, distilled water gained using rotating mode was about 64% more than the fixed mode. Both the rotating and fixed mode yield for two cloudy days with respect to the average yield of sunny days decreased by 47 and 53%, respectively.

A Solar still is a viable option when the demand of potable water does not exceed more than 3 litres. Enhancement in distillate output from the Solar still is a main goal of many researchers all over the world. In this research, the effect of copper and aluminum plates on distillate output is investigated experimentally as well as theoretically at different water depths under the same climate conditions. In Solar stills, first we used Solar still augmented with copper plates, second with aluminum and third without any plate called passive Solar still. An energy balance equation was applied to Solar still for calculation of theoretical distillate output of a Solar still with different plates. Three experiments still of 1 m2 in area were constructed from locally available materials. In this work, it was found that the experimental and theoretical results are in good agreement. It was also found that using copper plate in a Solar still increases distillate output by 20% (at water depth of 3 cm) and 32% (at water depth of 6 cm) compared with passive Solar still, and using an aluminum plate increases distillate output by 10% (at water depth of 3 cm) and 20% (at water depth of 6 cm).

Solar still is a green apparatuses for seawater desalination that can be a replace of common method of seawater vaporization using fossil fuel and condensing it, especially in Persian Gulf with hot weather which has a high radiation power of sun in summer when drinking water resources are limited. Solar still works using Solar radiation that is a renewable source of energy and reduces the production of pollutant and greenhouse gases that produced using fossil fuel in a normal process. Therefore, commercialization of Solar still is in direction of sustainable development. In this article, a Solar still was modeled mathematically for describing the effect of parameters on performance of this device. Energy and mass balance equations were written using lumped formulation. Set of ordinary differential and algebraic equations was solved numerically using MATLAB software. Iteration method was used for estimating implicit heat transfer coefficients that are a function of temperatures. In this model effect of water depth and different daily Solar profile was studied on total amount of water production. Temperature of basin water as a function of time was obtained by changing water depth, cycle number and Solar flux profile. The cycle of still process was continued for several days without any brackish water make-up. The results show that at higher water depth, nightly desalinated water production continued more than lower water depth. The model indicates that at Muscat with higher Solar flux, the water production and maximum of basin water temperature are greater than Shiraz with lower Solar flux. It can be concluded that the potential of commercialization of Solar still in an area near the sea with high Solar flux is higher. But at lower initial water depth, the amount of water production at locations with lower Solar flux approaches to the locations with higher Solar flux.

In this study, an attempt has been made to develop a new correlation for the productivity of a single-basin double-slope Solar still using experimental results obtained for different brine depths (0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 m) in the basin in Coimbatore, Tamilnadu, India. The proposed correlation has been validated with the experimental results for one of the typical days in Coimbatore, Tamilnadu, India. A concluding correlation has been developed by including the results mentioned in the literature regarding double-slope Solar still alone and the proposed correlation. The concluding correlation is compared with the correlation developed by the researcher based on the results in the literature regarding both single- and double-slope Solar stills. The results indicate that the correlation coefficient R2 is slightly higher as compared with that of previous results obtained for both single- and double-slope single-basin Solar stills.

This article presents advancements in the working of Single slope conventional Solar still (CSS) through the integration of saltwater bottles. The saltwater contained within these bottles (totalling 40 in number) is dyed black to enhance its Solar radiation absorption ability. Using their high heat capacity, these bottles efficiently store Solar energy during peak radiation hours, subsequently releasing it during the evening or nocturnal periods. Results have demonstrated a consistent increase in the temperature of water within the Modified Solar still (MSS) compared to its typical counterpart, notably observed after 14:00 h. Moreover, the cumulative yield obtained from the MSS surpasses that of the CSS variant by 25.4%. Augmentation with saltwater bottles has increased the efficiency of MSS by 25% as compared to the CSS. Furthermore, incorporation of saltwater bottles results in a notable reduction in the cost of distillate production, with a decline of 20%, as compared to the CSS. The study emphasises how using saltwater bottles as thermal energy storage reservoirs in Solar distillation systems could have real-world applications. The results offer important information on enhancing the effectiveness and economic viability of water purification, especially in areas where there are issues with water scarcity.

This project mainly focuses on maximising the production of distillled water by emphasizing three important factors: decrease in depth of water, increase in exposure area and temperature of the saline water. In this work, to augment the evaporation and temperature of the still basin water, the basin is made by glass material because of its good absorption. The stepped type basin is composed of four trays. Each tray is detached into top and bottom trays. The depending water enters the top trays (evaporating zone) where evaporation takes place depending on depth provided by the glass strip. The overflow water driven to the bottom tray (heating zone) through the gap provided in the separation glass will be further heated and made to flow through the subsequent trays. Modifications such as sponges to increase the exposure area, sensible heat materials like sand, and metal scraps to increase the saline water temperature, glass cubes with dry salt, camphor, aluminum scraps and charcoal to increase both saline water temperature and exposure area showed subtle improvement in the production rate. Experimental results were compared with ordinary basin type still. Theoretical evaluation was also done and is closer to the experimental values.

Desalination could be a sustainable solution for responding to the ever-rising demand for water and the scarcity of freshwater resources. But given the substantial energy consumption of conventional desalination methods, greater use of renewable energies such as Solar in this area seems inevitable. This study investigated the effect of placing sand within the basin of a simple basin-type Solar still on its performance. For this purpose, two Solar stills one with a sand-containing basin and the other without sand, were designed and constructed. The stills were then tested in Sabzevar (latitude: 36. 20; longitude: 57. 67), Iran, to determine the effect of sand. The tests were carried out over three days in early July 2019 for 13 hours each day. The results showed that the presence of sand within the basin of the still increased its water productivity and thermal efficiency by 21. 16%. Considering these results and the low cost and high availability of sand, placing sand inside the basin of the Solar still appears to be a good solution to increase its efficiency.