In Situ Latent Heat Transfer for Nearly 100% Condensation in Single-Stage Interfacial Solar Steam Generation

Interfacial solar steam generation is considered a promising alternative for freshwater production. Although efforts have been invested in enhancing the evaporation rate (ER), considerable discrepancies exist between the ER and the actual collection yield when used in practical devices. Here, we prepared a solar water purifier with a conical evaporator and a cylindrical condenser of the same diameter and achieved nearly 100% steam condensation efficiency by conducting the wastewater through the condenser surface via capillary action. A 2.5-fold increase in the water collection rate (CR) in a single-stage solar water purifier was achieved compared to conventional solar stills, irrespective of the absorber materials and illumination intensities. The high CR/ER ratio in this solar water purifier was attributed to the efficient in situ latent heat transfer from steam to the reservoir that maintained the condenser at a lower temperature, enhancing the steam condensation. A simple and cost-effective design technique with high water collection yield, this work provides a promising pathway toward portable and personalized freshwater generation in remote areas.