Thermohaline Convection-enhanced Solar Membrane Distillation: A Sustainable Approach to Global Water Security

Abstract

The Thermohaline Convection-Enhanced Solar Membrane Distillation (TSMD) system is introduced as an innovative and sustainable solution to global water scarcity, designed to operate entirely off-grid using renewable energy sources, primarily solar thermal power, for an optimal eight-hour daily cycle. Unlike conventional desalination systems dependent on grid electricity or fossil fuels, the TSMD incorporates a 12 V DC submersible pump powered by a 15 W solar panel, a 12V-7Ah battery ensuring semi-autonomous operation in remote or resource-limited regions. The design integrates thermohaline convection and a pump to enhance heat and mass transfer, improving evaporation and condensation efficiency. Experimental results from hardware testing indicate a freshwater production rate of approximately 5.4 L of freshwater from 10 L of feedwater (54% water recovery), with brine discharge maintained at about 4.6 L. Total Dissolved Solids (TDS) levels were significantly reduced, reaching as low as 109 ppm, far below the WHO drinking water threshold of 300 ppm. Under peak sunlight conditions, the system achieved a thermal efficiency of approximately 62%. These findings demonstrate that the TSMD system is environmentally friendly, and its energy-independent design makes it a strong potential for solving the freshwater shortages in arid, semi-arid, and off-grid communities around the globe.