Investigation on solar humidification dehumidification water desalination system using a closed-air cycle

Abstract

Recently, many regions of the world have become in an urgent need of desalination systems. Humidification-dehumidification desalination plants are considered the most suitable choices for many countries. Many of the previous studies have worked on the study of humidification-dehumidification desalination systems based on the open-air cycle. The current research presents a theoretical and experimental study of a solar humidification-dehumidification water desalination system based on a closed-air cycle. The impact of air flow-rate, water to air mass ratio, and cooling water flow-rate on gain output ratio and water productivity has been investigated. The results show that the productivity is enhanced with increasing air flow-rate, while the gain output ratio decreases. The gain output ratio and productivity improve with raising the water temperature. The average value of gain output ratio is 0.71, 0.74, 0.78, and 0.81, and the productivity reaches 1.46 kg/h, 2.59 kg/h, 4.40 kg/h, and 6.99 kg/h at water temperatures of 40 °C, 50 °C, 60 °C, and 70 °C, respectively. The maximum gain output ratio of 0.86 is recorded at water to air mass flow-rate ratio of 5. Increasing the cooling water flow-rate has a positive effect on both productivity and gain output ratio. Moreover, the results indicate that the fresh water cost is 0.012 $/L. Finally, a good agreement is noted between the theoretical and experimental results.