A Review on the Impact of Condenser Technologies on Solar Still Productivity

To scientifically address the low productivity issue of traditional solar desalination systems, the current review intends to investigate the effect of design changes and performance improvement of solar stills with external and internal condensers. This review highlights that elements such as coolant techniques, the geometry of the condenser, and material features (e.g., nanofluids or surfaces of wettability) have a pivotal impact on maximising output. The results show that the combination of external condensers in solar stills is remarkably effective, where the efficiency ranges between 24% and 165% in distillate yield depending on the design modifications, which include the use of nanofluids, reflectors, and phase change materials (PCMs). In this regard, internal condensers explicitly display significant performance advances, with water production improvements of more than 150% in improved stepped designs and 60% in capillary film designs. To guarantee the maximum production of fresh water, this review proposes a number of adjustments to elevate the overall performance of solar stills, such as condensers with enhanced mechanisms of heat transfer or passive cooling strategies, which enable solar stills to be more practical in achieving the sustainable desalination of water across a wide range of climatic regions. Indeed, the enhancement of the efficiency of solar desalination technologies would support the United Nations Sustainable Development Goal 6 (Clean Water and Sanitation), providing access to safe and affordable drinking water for all.