Experimental evaluation of membrane distillation and bubble column dehumidifier bank desalination system for Balancing productivity and energy efficiency

This study introduces an innovative integration of a sweeping gas membrane distillation system with a bubble column dehumidifier bank, specifically designed to optimize both productivity and energy efficiency in desalination processes. Experimental evaluation demonstrated that increasing feed temperature from 50 °C to 80 °C resulted in a 338 % increase in flux and a 70 % reduction in specific energy consumption. Additionally, increasing the feed flow rate from 2.6 L/min (Laminar flow) to 4.6 L/min (turbulent flow) improved productivity by 40 %, even with a slight increase in energy consumption. Furthermore, adjusting permeate pressure from 650 mbar to 400 mbar not only doubled the gained output ratio but also decreased energy consumption by 48 %. The novel use of a bubble column dehumidifier effectively reduced air temperature by 28 °C without additional energy, underscoring significant advancements over conventional methods. Our findings suggest that this configuration offers a substantial improvement in cost-effectiveness, achieving a water production cost for the lab-scale system of 30–32 $/m³ at best operational parameters, making it a viable solution for enhancing water desalination efficiency.