One of the common water desalination apparatuses in freshwater regimes is Single Slope Solar Still (SSSS). This paper numerically investigated the heat transfer processes that took place inside the still. Also, implementing an optimization process to explore the best sustainable feed water preheating tank design. Comsol Software package (v 5.4) was utilized to develop and validate the 3D Mathematical model. The investigation included comparing four different tank designs namely are sphere, half-sphere, cone, and flat plate. In addition, the influence of altering the volume of the tank has been considered. The study revealed that the half-sphere design with a volume of 2.5 times the productivity of Conventional SSSS accompanied the highest recorded water temperature and productivity. The efficiency of the SSSS was enhanced by 27% in contrast to that without preheating.

The growing demand for freshwater is a challenging task facing human society due to the rapid rise of the global population. Solar distillation emerged as an economical, environmentally friendly practical technology to produce freshwater. Solar still is a proven technology to produce clean water and removing dissolved and solid impurities as well as chemical hazardous, organic bacteria, and non-organic contaminants. Rural and remote regions that suffer from impure water can beneficiate this technique. However, the daily productivity of single slope solar still SSSS is questionable. Hence, several researchers focused on enhancing the productivity and efficiency of SSSS through adopting a wide range of modifications. This review reports various modification techniques that have been investigated to improve SSSS efficiency and clean water productivity. It mainly considered modifying the absorption plate, thermal energy storage, utilization of reflectors, adopting nanotechnology, integrated condenser, cover cooling, Humidification-dehumidification HDH, and Basin water preheating technique.