Membrane-type Total Heat Exchanger Performance Simulation with Consideration of Entrance Effects

Membrane-type total heat exchanger (THX) is an air-to-air heat exchanger used to reduce the building energy consumption associated with forced ventilation by recovering both heat and moisture from ventilation air. It contains a heat/moisture exchange core made of a water vapour permeable membrane, supply outdoor air and exhaust indoor air flow through the membrane channels in the core in a crossflow manner and exchange heat and moisture across the membranes. The present work numerically investigates the airflow channel entrance effects on the THX performance. The results show that such effects on the air temperature and humidity distributions are inconspicuous and so are they on the THX effectiveness, it is therefore appropriate to use the constant Nusselt number to evaluate the THX performance.