A parametric analysis of a solar humidification/dehumidification desalination system using a bio-inspired cascade humidifier

Water scarcity is a significant challenge for a growing world's population, particularly in remote locations where solar energy is plentiful. Of the existing solutions, the Humidification-Dehumidification (HDH) desalination technique can work effectively with low-grade energy sources, such as solar. However, HDH desalination systems often have a low yield, leading to a focus on ever-more complex humidification systems. This work aims to examine the performance of a novel bioinspired humidifier as a low-cost and effective solution to increase the yield of small-scale HDH desalination systems. To this end, an HDH desalination system using a cascade humidifier was conceptually developed and parametrically modelled. It was shown that the evaporation rate in the humidifier could be increased by increasing both the air and water flow rates. It was also found that an evaporation rate of 0.91 x 10-3 kg/s could be achieved for an evaporation area of 0.36 m2. Considering the entire desalination system, it was noted that increasing the water flow rate reduced the water temperature entering the humidifier and thus reduced production. Conversely, increasing the airflow rate enhanced the production rate. More importantly, it was shown that under appropriate conditions this novel desalination system can have a production of 10.2 litre/day/m2.