Research On The Mechanism Of Absorption Process Using LiBr Solution And Hollow Fiber Membranes As Well As The Production Of Refrigeration Device

Compared to vapor compressing refrigeration, direct evaporative cooling is more environmentally friendly and energy-saving. However, the environment with high humidity would be a disadvantage to humidifying cooling. Pre-dehumification by a module combining hollow fiber membranes and LiBr solution might be a good method to solve this problem. Hence, in-depth research to this dehumidifying method would be meaningful.In order to study the mass transfer mechanism using hollow fiber membranes and LiBr solution to dehumidify the moist air, numerical simulation and experimental methods have been applied. With mathematical software Matlab, the intensity of mass transfer under different conditions of inlet liquid velocity, concentration and temperature, as well as the gas flow velocity has been investigated. The distributions of solution temperature, solution concentration, vapor concentration within the membrane and vapor concentration outside the membrane have been obtained. The location of the gas-liquid interface under different liquid pressure has been confirmed through checking the existing of residual LiBr crystal within the membrane with SEM. Increasing the liquid flow velocity and inlet liquid concentration, as well as reducing inlet solution temperature would be beneficial to the mass transfer process. Increasing inlet solution concentration would be the most effective one.In terms of experimental method, self-designed and self-made hollow fiber membrane module and air-conditioning prototype have been tested. Their performances in varied ambient condition have been learned. The high temperature and dry air would do good to the enhancement of their performances. Refrigeration capacity increases as the higher ambient temperature. In moist environment, hollow fiber membrane module would raise the refrigeration capacity by 63%～69%. Hence, the self-made membrane module could improve the performance of direct evaporative cooling and has a prospect for application.