Feasibility of desalination by solar stills for small community scale freshwater demand

Solar stills are conventional desalination systems based on direct solar heating. While their productivity is limited, their simple construction and low maintenance requirements makes them an attractive and feasible option for community-scale desalination. This study shows that low-cost solar stills are capable of producing sufficient freshwater for small disadvantaged communities at costs lower than competing technologies. A variety of solar still materials are investigated showing that the cost of freshwater produced is sensitive to the solar still cost. Inexpensive carbon black particles dispersed in the water are used to increase solar still performance, and a set of low-cost solar still materials are identified from a pool of candidate materials to minimize water production cost by means of optical and energy analyses. In addition, communities with fewer than 10000 residents are identified in the reference region of California to perform an energy analysis to determine freshwater productivity yield and the cost of freshwater production. It is determined that a 10000 m2 solar still could produce freshwater meeting the requirements of small rural communities costing less than $ 7.71 /m3. Attractive investment options are available that could reduce the cost of water produced to less than $ 1.75 /m3. Solar stills were found to be feasible when comparing the cost of freshwater produced with a comparable photovoltaic reverse osmosis system. The proposed methodology can be extrapolated to determine the feasibility of solar still-based desalination systems in other geographical locations. From the results of the analysis, solar stills are proposed for effectively producing low-cost freshwater to increase the accessibility of freshwater in small rural communities.