Modeling and optimization of heat and mass transfer in solar-driven desalination still

Abstract

Solar-driven desalination (SDD) is one of the most promising approaches to solving the freshwater shortage. By far, the overlay-structured and underlay-structured solar stills are two kinds of solar stills commonly used to reclaim the fresh water. However, the lack of universal mathematical models and clarity about the quality of various optimization strategies limit the further development of SDD technology. Herein, a mathematical modeling calculation has been applied on the heat and mass transfer process of both the overlay-structured solar still and the underlay-structured solar still. The calculation results reveal that the underlay-structured still has a water productivity 169.68% higher than the overlay-structured still. Moreover, several optimization strategies have been studied and evaluated to provide some reference for those who are engaged in SDD research. Thermal localization treatment and changing the coolant from air to feed solution have the best optimization effect, and the water productivity calculated by corresponding solar still models increases by 444.86% and 45.69% respectively. This work provides powerful models and useful guidance for the design of SDD stills.