Improving thermal, economic, and environmental performance of solar still using floating coal, cotton fabric, and carbon black nanoparticles

This manuscript presents the enhanced thermal, economic, and environmental performances of single slope solar still utilizing eco-friendly and available materials, namely: floating coal, cotton fabrics, and carbon black nanoparticles. These additives were proposed as coal can attain heat localization effect besides having moisture absorption and capillarity ability. In this regard, cotton can emphasize the capillarity effect, and carbon black nanoparticles can enhance the thermal properties, especially thermal conductivity. The modified solar still was tested and theoretically analyzed compared to a traditional reference solar still. Based on the proposed materials, three cases were studied: modified solar still-A (coal only), modified solar still-B (coal covered with cotton fabrics), and modified solar still-C (carbon black nanoparticles dispersed atop coal/cotton combination). Besides the productivity, the performance was evaluated thermally based on energy and exergy efficiencies and enviro-economically based on 4E analysis (economic, exergoeconomic, exergoenvironmental, and exergoenviroeconomic). As result, the proposed improvements attained feasible and eco-friendly performance. The highest improvements in accumulated yield, average energy efficiency, and average exergy efficiency were obtained from modified solar still-C by 59.33, 75.12, and 142.7%, compared to reference solar still, respectively. In addition, in this case, the production cost could be saved by 25.32%, and the carbon emission mitigation could be increased by 127.5%.