Air-side Thermal Performance of Brazed Aluminum Heat Exchangers Under Dehumidifying Conditions

Abstract

An experimental study for air-side thermal-hydraulic performance of brazed aluminum heat exchangers under dehumidifying conditions has been performed. For 30 samples of louvered fin heat exchangers with different geometrical parameters, the heat transfer and pressure drop characteristics for wet surface were evaluated. The test was conducted for air-side Reynolds number in the range of 80-300 and tube-side water flow rate of 320 kg/h. The dry- and wet-bulb temperatures of the inlet air for heat exchangers were 27 and 19 degreesC, respectively and the inlet water temperature was 6 degreesC. The air-side thermal performance data for cooling and dehumidifying conditions were analyzed using effectiveness-NTU method for cross-flow heat exchanger with both fluids unmixed. The test results are reported, compared with those for the dry surface heat exchangers, in terms of sensible j factor and friction factor f, as functions of Reynolds number based on louver pitch. The correlations for j and f factors are developed within rms errors of +/-16.9 and +/-13.6%, respectively. (C) 2002 Elsevier Science Ltd and IIR. All rights reserved.