Impact of packing configurations and thickness on the performance of filtration humidifier

• Celdek 7090 packing outperformed both Celdek 5090 and corrugated packings. • The COP and efficiency were found as 2.15 and 85.57 %, respectively. • Packing using grey water releases more contaminants than when using salt water. • Greater packing thickness enhances humidification performance and reduces pollution. • Increased wettability improves overall humidification efficiency. The current study centers on the design and fabrication of a direct-type evaporative cooling unit utilizing gray and salt water as working fluids. Three distinct packing configurations—Celdek 7090, Celdek 5090, and corrugated—were incorporated into a counterflow humidifier system to evaluate their performance in both humidification and water filtration. The air Reynolds number varied from 32,596 to 58,674, with performance metrics assessed across different packing configurations, wettabilities, and fluids. The system achieved an evaporation rate of 0.1158 g/s, a coefficient of performance (COP) of 2.15, a humidification efficiency of 85.57 %, and a cooling effect of 251.35 W, with Celdek 7090 outperforming the other configurations when paired with salt water. As packing thickness increased for gray water, CO 2 levels decreased by 5.83 %, 6.19 %, and 6.55 % for the Corrugated, Celdek 5090, and Celdek 7090 packings, respectively. Formaldehyde (HCHO) concentrations were reduced by 38.09 %, 40 %, and 38.88 %, while total volatile organic compounds (TVOC) decreased by 21.73 %, 23.80 %, and 26.31 %. Pollution levels were found to rise with increasing Reynolds number, yet tests confirmed that the air leaving the system was of superior quality. Enhanced packing thickness not only improved humidification performance but also further reduced pollution levels.