Performance optimization of indirect evaporative cooling heat exchanger with porous copper foam

Abstract

This study established a heat and moisture transfer model to optimize the coupled heat and mass transfer performance of indirect evaporative cooling (IEC) systems. The numerical results indicate that the air counterflow arrangement and improved surface water film coverage are effective strategies for enhancing IEC heat transfer capacity. Guided by the simulation-based optimization, a novel IEC heat exchanger with porous copper foam covered working air channels was developed. The experimental results indicate that the novel IEC heat exchanger can achieve excellent cooling capacity due to the high thermal conductivity and porous structure of the porous copper foam, and a maximum heat flux improvement of 50.7% is observed against the traditional IEC. Benefiting from the favorable water-retention property of porous copper foam, the auxiliary energy consumption of the IEC system is reduced, and the system coefficient of performance is greatly improved, reaching up to 440.49. The condensation of the product air significantly reduces the product air temperature variation and wet-bulb efficiency but raises the heat transfer rate. Experimental data shows that under the low humidity ratio condition, the wet-bulb efficiency and heat transfer rate are 55.2%–73.2% and 50.7–105.3 W, respectively, while under the high humidity ratio condition, they are 41.4%–59.1% and 88.2–151.7 W, respectively.