Energy saving potential in humidification-dehumidification desalination system

- Developed an economical HDH desalination system for productivity enhancement.
- Inserts in air heater and de-humidifier amplified the system efficiency.
- Productivity increases significantly with saving of power and total cost.
- 40% of input power saved in modified HDH system compared to conventional system.

Humidification dehumidification desalination (HDH) system is viewed as an auspicious technique for medium level investment and productivity. The objective of this work is to enhance the productivity with the saving of input power in a modified HDH system by various changes in its components. Inserts like short length taper twisted tape; internally finned cut out conical turbulator and half perforated circular inserts with various orientations and three different pitch ratios (PR) are used in the air heater. Two types of packing materials (Gunny bag and saw dust) are employed in humidifier section and two different dehumidifier are tested to choose the good one and it is further integrated with spring inserts of different PR to enhance its performance. The best combination is identified when the air heater equipped with divergent twisted tape of PR 3, humidifier furnished with gunny bag and dehumidifier fixed with spring insert of PR 3. Higher productivity of 0.8 kg/h with the reduction in salinity (3.2 mg/l of chloride content) attained with 40% saving of input power in the modified HDH desalination system. A noticeable saving in energy with significant development in energy and exergy efficiency is observed. The economic analysis is also carried out.