Performance and exergy analysis of vacuum-assisted sweeping air membrane distillation and bubble column dehumidifier

Abstract

This study provides a comprehensive theoretical analysis of an integrated Sweeping Gas Membrane Distillation (SGMD) and Bubble Column Dehumidifier (BCD) system for cost-effective water desalination. Analytical investigations on this novel system are not available in the literature which represents a knowledge gap. The current analytical study offers insights into the efficiency of the integrated SGMD-BCD system, identifies optimal operational conditions, and provides benchmark data for future scaling-up and commercialization. The theoretical model, based on solving heat and mass transfer equations, is validated against the experimental data. An exergy analysis of the integrated SGMD-BCD is considered to explore the possible improvements in the design and operation for enhanced performance. Results reveal a peak GOR of 0.41 under maximal tested feed flow rates and temperatures, coupled with minimal air flow rates and air channel pressures. The BCD achieves maximum effectiveness in the range of 0.95–0.98 at feed temperature of 90 °C. Exergetic efficiency reaches its peak at 3.25%, observed at the lowest feed flow rate (1 L/min) and temperature (40 °C). Notably, the SGMD process exhibits 18 to 20 times the exergy destruction compared to the BCD at a 90 °C feed temperature, highlighting the need for improvements in its design and operation.