Experimental Study on the Factors Influencing the Heat Transfer Coefficient of Vertical Tube Indirect Evaporative Coolers

This study looks into the parameters that affect the heat transfer coefficient (h2) on the wet surfaces of vertical tube indirect evaporative coolers (VTIEC). An experimental platform was used to investigate the impact of secondary-to-primary airflow ratios (AFR) and spray water density on the HTC. The findings show that raising the primary air temperature drop, expanding the outside dry-bulb and wet-bulb temperature differences, and decreasing the air-to-water ratio improve heat transmission. The HTC of the wet sides ranged from 34.79 to 924.5 W/(m2·°C) throughout testing. To achieve optimal performance, aim for a spray water density of 2.07 to 3.46 m3/(m2·h), an AFR of 0.5 to 0.6, and a primary air temperature drop of at least 6 °C. These factors help keep the h2 above 350 W/(m2·°C).