Numerical study of heat and mass transfer in an enthalpy exchanger with a hydrophobic-hydrophilic composite membrane core

Abstract

Coupled heat and mass transfer in an enthalpy exchanger with a membrane core is investigated numerically. The membrane is composed of two layers: a hydrophobic porous support layer and a hydrophilic dense active layer, which is used to selectively transfer moisture from a stream of fresh air to an exhaust air. Contrary to the common treatment of the membrane as a black box, the transport mechanisms in the two-layer composite membrane are included in the model. The equations governing the heat and mass transport in the microstructure, as well as the transfer of momentum, energy, and moisture in the rectangular flow passages, are solved numerically in a coupled way. The temperature and humidity profiles on the membrane surfaces exhibit nonuniform value nonuniform flux behavior. The largest moisture resistance in the composite membrane is from the support layer, while the heat resistance of both the support layer and the active layer is negligible.

This project is jointly supported by National Natural Science Foundation of China (50306005), Fok Ying Tung Education Foundation (101057), and Natural Science Foundation of Guangdong Province (05006557).