Experimental Assessment of Metal Foam and Louvered Fins as Air-side Heat Transfer Enhancement for Miniaturized Condensers

An experimental investigation was conducted to evaluate and compare the thermal-hydraulic performances of crossflow microchannel condensers using louvered fins and metal foams as extended surfaces. Three copper foam surfaces with pore densities of 10 and 20 PPI and porosities of 89.3% and 94.7% were compared with three aluminum louvered fins with lengths of 27 and 32 mm (in the flow direction) and heights of 5 and 7.5 mm. The experiments were carried out in a closed loop wind-tunnel calorimeter equipped with a R-600a refrigeration loop. A condensing temperature of 45°C was used in all tests, with face velocities ranging from 2.1 to 7.7 m/s. A comparison based on the air-side thermal conductance and pumping power per unit volume showed that the louvered fin surfaces performed better than the metal foams for all conditions investigated.