Experimental Evaluation of PVA as Novel Humidifier Material for Humidification-Dehumidification Applications

Abstract The humidification-dehumidification (HDH) desalination technique is a promising technology to harness fresh water, resulting in a decline of scarcities of remote and arid area water. The humidifier unit is one of the major functional elements in an HDH desalination system. The efficiency of any HDH desalination system predominantly depends on the individual humidification and dehumidification process potential. Therefore, improvement in the humidification (or) dehumidification process potential can substantially improve the system’s overall performance. In this work, an attempt has been made to utilize polyvinyl alcohol (PVA) as novel humidifier material for the humidification process. The experimental study was carried out considering diverse inlet air velocities of 3, 2, and 1 m/s. Different cases with and without air preheating were experimented to evaluate the humidification potential of PVA material when utilized in an HDH desalination system powered by waste heat and ambient conditions. The results revealed that the rate of evaporation from PVA material was predominantly influenced by the ambient air temperature compared with other system parameters. Furthermore, comparatively, it was found that, with the use of PVA as humidifier material, average increases in relative humidity of about 19 and 10 % were achieved for higher air velocity of 3 m/s in the cases with and without air preheating, respectively. Thus, it was identified that PVA can be utilized as an effective humidifier material for efficient humidification processes in HDH desalination systems.