Simulation of heat and mass transfer in solution heat exchanger with hollow fiber membrane

A solution heat exchanger with hollow fiber membrane applied in lithium bromide absorption systems was proposed. Unlike in conventional dividing wall type heat exchangers, water vapor mass transfer occurs with heat transfer and the direction of mass transfer depends on the water vapor pressure difference between the two sides of membrane. A mathematical model of heat transfer and mass transfer process in the membrane heat exchanger was established with the distributed parameter method, and its performances with the parallel-flow mode and the counter-flow mode were compared. The simulation result shows that with the counter-flow mode, the temperature difference is uniform along the flow path, and heat transfer and mass transfer are more steady. The rich solution can be concentrated and the weak solution can be diluted further, leading to lower heat loads of the generator and the absorber.