Numerical Study of Indirect Evaporative Cooler Using Porous Media with Dynamic Time-independent Performance Prediction

Abstract

Air conditioning systems consume a large amount of energy with the rising living standard of human beings. Indirect evaporative cooler, which is increasingly recognized as a promising alternative to partially substitute conventional air-conditioning devices, has been studied extensively to improve the cooling efficiency and save energy in buildings.Using porous media in the indirect evaporative heat exchangers is a critical approach for performance enhancement. This paper established a two-dimensional plate-type counterflow indirect evaporative cooler model with porous media on the secondary air channel surface. On the one hand, the porous structure was incorporated in the model to alter the boundary layer and flow status. On the other hand, the water retention ability of porous media that potentially improves the surface wettability has been proven to enable the intermittent operation of the water pump. The influence of various porous parameters, i.e. porosity and pore diameter, on the time-independent dynamic variation of the outlet primary air temperature have been quantitatively analyzed. This study provided a theoretical foundation for the studies of the porous plate-type indirect evaporative cooling technology.