Techno-economic assessment of carbon-based nanofluid dispersions in solar stills for rural coastal locations in the Northern and Southern hemispheres

Abstract

Accessibility of freshwater in remote rural regions where the demand is merely of the order of 1 to 100 m3/d is limited. Low-cost freshwater productivity in those regions can be fulfilled by simple solar stills with inexpensive carbon particle dispersions to enhance the absorption of solar energy near the evaporating surface. In this manuscript, the techno-economic and environmental assessment of such a solar still with low-cost nanoparticle dispersion is performed for two rural coastal locations of Big Sur (U.S.A) in northern hemisphere and Chan˜aral (Chile) in southern hemisphere and compared against competing solar desalination technologies, that is, solar collector integrated humidification dehumidification (FPC- HDH) and photo-voltaic seawater reverse osmosis (PV-SWRO) system. Real time year-round solar irradiation and ambient conditions data are utilized for the energy analysis.The expected daily freshwater productivity is around 3.5 and 5 m3/d for a 1000 m2 solar still and FPC-HDH system. For similar rates of freshwater productivity, 200 m2 PV-SWRO system is sufficient. The annual greenhouse gas emissions mitigated by thermal systems was around 200 ton/y, while for PV-SWRO was only 50 ton/d. Economic analysis showed cost of freshwater production with solar still to be lower than PV-SWRO at around $8/m3. A feasibility analysis of low-cost parameters showed that the unit cost of freshwater can be lower than $3/m3 with solar stills, which is much lower than PV-SWRO system