Enhancement of solar desalination by humidification-dehumidification technique

Abstract

This paper presents experiments for increasing the fresh water yield from water desalination by humidification-dehumidification technique (HDT). The scheme of this system is to increase the humidification rate by increasing the surface area for the purpose of efficient contact between water and air, which can be accomplished by misting the saline water within the air stream, thus the rate of fresh water production increases. A parabolic trough was used to heat the saline water. It appeared that it takes three hours to raise 25 l of water from 35 to 70°C, this time was insufficient to fulfill the continuous saline water feed to the humidification-dehumidification (HD) unit, and thus electric heater was used to raise the temperature of the saline water to the desired degree. The results of HD unit showed that water production depends on both saline water temperature and droplet size. The maximum attainable water production was 31.7 l/d/m2 of solar water heater at 85°C. For this experiment, the humidity of c...