Abstract: The airside heat transfer and pressure drop characteristics of 7 hydrophilic coated and 3 uncoated wavy fin-and-tube heat exchangers are studied under dehumidifying conditions experimentally. Airside performances under dry and wet conditions are compared at different inlet air velocities and different inlet relative humidity. The test results indicate that for the hydrophilic coated wavy fin, pressure drop under dehumidifying conditions is pronouncedly higher than that under dry conditions; when the inlet velocity is less than 0.5 m/s, heat transfer performance under dehumidifying conditions is lower than that under dry conditions; when the inlet velocity increases to 2.0 m/s, heat transfer performance under dehumidifying conditions is better than that under dry conditions. The heat transfer performance of wavy fin with hydrophilic coating is slightlyly lower than that of uncoated wavy fin under dehumidifying conditions, but the pressure drop of wavy fin with hydrophilic coating is pronouncedly lower than that of uncoated wavy fin. The airside heat transfer and pressure drop correlations of wavy fin-and-tube heat exchangers under dehumidifying conditions are proposed and the mean errors are 8.70% and 7.90%, respectively. These correlations can be used to design wavy fin-and-tube heat exchangers or to evaluate their performances.

Key words: Correlation, Dehumidifying conditions, Heat transfer, Wavy fin