A Simplified and Robust Design Procedure for Humidification-Dehumidification Systems with Air Extractions

Abstract

This study presents a streamlined methodology for designing thermally optimized humidification-dehumidification systems that operate with zero, one, or two air extractions. The developed method is a direct model that integrates system sizing with performance predictions, emphasizing the correlation between key performance indicators and design parameters. The model requires inputs including saline-water salinity (0–100 ppt), minimum and maximum temperatures (20–40 °C and 60–80 °C), enthalpy pinch (1 kJ/kg to the critical limit), and air extraction count (0–2). It underpins extensive datasets that derive design correlations for evaluating metrics such as gain-output ratio, mass flow rate ratio, recovery ratio, energy efficiency, and critical enthalpy pinch. Additionally, essential elements of design, like the humidifier's volume and the dehumidifier's surface area, are carefully evaluated. Offering broad operational flexibility and achieving accuracy within 5% when validated against literature, this model enhances the applicability of humidification-dehumidification systems in real-world settings. This approach provides a practical and robust predictive tool, offering significant utility to engineers and researchers in designing energy-efficient and adaptable humidification-dehumidification desalination systems across diverse conditions.