Considering desalination, many techniques have been developed last decades to provide fresh water in arid and water-scarce places where there is usually saline water from lakes, groundwater or sea. Although about 71% of the earth's surface is covered by water, over 97% of the water is salty and unsuitable for human consumption. Different desalination techniques can be classified into membrane and non-membrane techniques. Considering the techniques with the use of membranes stands out the reverse osmosis, where a high-pressure pump is needed to transport the saline particles from a lower concentration medium to a higher concentration. Evaluating membrane-free techniques highlights three technologies: Multi-Stage Flash (MSF), Multi-Effect Distillation (MED) and Humidification-Dehumidification (HDH) systems. It is noteworthy that both MSF and MED require the use of water stem (at 100°C), requiring a lot of thermal energy to perform the entire process.

Focusing on HDH desalination systems and aiming to develop a compact and simple system for home use, the present paper shows an analytical and experimental study to evaluate the performance of a new configuration of direct contact HDH system with the humidification and dehumidification system in the same enclosure, without the need for air transfer ducts (humid air) and the system operates on natural convection without the need for systems to promote airflow.

An analytical model was developed for calculating HTC on the external hydrophilic surface of the evaporator and evaporated water mass, based on mass and energy balance. Experimental tests were performed with the inlet evaporator water temperature ranging from 42 to 67ºC, at a flow rate of 2.3E-6 m³/s (138 mL/s) and a condensation rate (drinking water) ranging from 0.5 kg/day was obtained. The analytical model showed good agreement with the experimental results and considering the system area of approximately 0.008m² (4” internal diameter), a daily production of up to 62,5kg/m²·day was obtained, showing a promising configuration for development of a practical simple and compact desalination system.


Performance Evaluation of a New Configuration of Direct Contact Humidification Dehumidification (Dchdh) Desalination System

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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