Systematic Study of the Effects of System Geometry and Ambient Conditions on Solar Steam Generation for Evaporation Optimization

Solar steam generation as an emerging solar desalination technology has drawn tremendous research attention owing to its enticing prospects in tackling the rising water crisis across the globe. Despite the numerous reports on materials with high evaporation rates, little is known about how the system geometry and ambient conditions impact the evaporation rate. The ambient relative humidity (RH), which can potentially impact on the evaporation process in the system is one such element that is not well studied. In this work, microchanneled balsa wood is employed as the research model in the quantitative investigations of these effects from the system itself and ambience. Direct implications and the interaction of various factors like ambient RH, hydrophilicity and specific weight of the material, carbonization thickness, and the water salinity are outlined. The trade-off between surface water content and the interfacial temperature is revealed, and interestingly, a local low-humidity zone is observed over the system's evaporation surface, which can sustain the evaporation even at extremely high RH. By tuning the system/ambience interactions, a systematic approach toward realizing the full potential of steam generators with optimized evaporation rate (10-20% enhancement) is therefore deemed achievable.