Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Dr. Yingchen Yang

Second Advisor

Dr. Javier Ortega

Third Advisor

Dr. Maysam Pournik


Freshwater is a limited and precious resource. Currently, half a billion people in the world face sever water scarcity all year round. Humidification dehumidification (HDH) systems have received special attention among the variety of small-scale desalination technologies due to its potential to create affordable and sustainable seawater desalination, especially when combined with natural power sources such as waves, wind, and solar rays. Improvements in the development of HDH desalination systems have been achieved in recent years. Nonetheless, the improvements that have received most attention focus on solar heaters and humidifiers. Dehumidification systems have often been adapted from air conditioning condensation systems rather than developed specifically for HDH applications.

This study focuses on the experimental design, testing, and analysis of a simultaneous direct and indirect contact dehumidifier using a bundle of parallel strings for HDH desalination applications. The use of cylindrical surfaces parallel to the flow to improve heat transfer has been widely investigated and utilized for indirect contact cooling (i.e shell and tube heat exchangers). However, there are limited investigations on the use of parallel strings to enhance direct-contact heat and mass transfer. Furthermore, the use of a bundle of parallel strings for the application of ocean-based humidification dehumidification (HDH) desalination has not been studied before.

Ocean-based systems introduce another level of complexity due to its remote location and weather exposure that requires the application of simple and robust designs. For this reason, the design under study is intended for applications which have no electric or electronic components, hence, improving its simplicity and costs by removing energy-requiring components (i.e. pumps, nozzles, sprays, etc). The dehumidifier under study solely relies on the use of highly efficient geometries introduced by the parallel strings to induce direct-contact heat and mass transfer and the ocean thermal energy for indirect-contact cooling. The application of the current dehumidifier is mainly centered on ocean-based HDH desalination technology; however, the general design concept could be implemented in other designs in which cooling, and dehumidification is desired for affordable and practical applications.


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