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Experimental and Analytical Investigation of RO-HDH Desalination System with Near Zero Liquid Discharge Approach Using Solar Energy

Behzadi Saroukolaei, Mohammad | 2025

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 58327 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saeedi, Mohammad Hassan; Shafii, Mohammad Behshad
  7. Abstract:
  8. The main objective of this study is to develop a hybrid desalination system combining reverse osmosis and humidification-dehumidification with the goal of near-zero liquid discharge. Two conventional humidification methods (packed bed and bubble column) were examined to achieve this goal. Notably, the studied system is a small-scale, off-grid system suitable for use in energy-scarce areas. This research involved numerical and experimental studies of the hybrid desalination system. Both humidifier types were studied to understand the humidification-dehumidification cycle performance better. The results indicated that the reverse osmosis cycle operates with a higher recovery rate by increasing feed temperature and pressure. The findings related to the humidification-dehumidification cycle showed that decreasing the evaporator and condenser temperatures optimizes system performance and increases the humidifier's efficiency. Additionally, as the salinity of the water rises, the system's output ratio decreases, but controlling the relative humidity and salinity temperature can compensate for this decrease. Increasing the height of the water column and the compressor speed improves the water production and overall performance of the bubble column humidifier-dehumidifier system. Furthermore, the results showed that the bubble column humidifier maintains high functional and economic stability across a wide range of salinities. The results of combining cycles also showed that the combined cycles of reverse osmosis and bubble column humidification-dehumidification with variable pressure perform well in terms of freshwater recovery factor. However, the salinity ratio of these cycles is not optimal due to the performance of the reverse osmosis cycle. Similarly, the combined cycle of reverse osmosis and high-temperature bubble column humidification-dehumidification has conditions similar to the variable pressure state. On the other hand, the low-temperature combined cycle has favorable performance in terms of freshwater recovery factor and salinity ratio. The low-temperature combined cycle can purify 99.68% of the feed water with a salinity ratio of 9%
  9. Keywords:
  10. Desalination ; Refrigeration ; Hybrid Desalination ; Near-Zero Liquid Discharge ; Humidification-Dehumidification ; Reverse Osmosis

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  • Bookmarks from Paper 01 - International Journal of Refrigeration (1st author)_compressed (2).pdf
    • Design and off-design analysis of a heat pump assisted humidification-dehumidification (HDHHP) desalination system for a wi ...
      • 1 Introduction
      • 2 System description
      • 3 Mathematical modelling
        • 3.1 Design condition step
          • 3.1.1 Governing equations of humidifier
          • 3.1.2 Governing equation of dehumidifier
          • 3.1.3 Governing equation of heat pump system
            • 3.1.3.1 Governing equation of compressor
            • 3.1.3.2 Governing equation of condenser
            • 3.1.3.3 Governing equation of expansion valve
            • 3.1.3.4 Governing equation of evaporator
        • 3.2 Off-design condition section
      • 4 Result and discussion
        • 4.1 System design in the first step
          • 4.1.1 Design of HP condenser
          • 4.1.2 Design of HP evaporator
          • 4.1.3 Design of humidifier
          • 4.1.4 Effect of design salinity and components sizing
        • 4.2 System design in the off-design step
          • 4.2.1 Off-design effect of inlet air temperature and saline water salinity
          • 4.2.2 Off-design effect of inlet air relative humidity and saline water salinity
          • 4.2.3 Off-design effect of temperature and salinity of saline water
          • 4.2.4 Off-design effect of the salinity and mass flow rate of saline water
        • 4.3 Comparison of GOR of the current cycle with the prevailing HDH systems
        • 4.4 Economic analysis
        • 4.5 Model validation
      • 5 Conclusions
      • CRediT authorship contribution statement
      • Declaration of competing interest
      • Acknowledgements
      • References
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