Absorption chiller, Hydrophobic membrane, LiBr, Automotive air conditioner
Automotive absorption refrigeration system has enormous potential to conserve energy using the exhaust gas from the car engine. The absorption system, however, has not yet been attracted to automobile application owing to its large volume, weight, and weakness for unexpected vibration and the slop while driving. By the vibration, the LiBr solution is scattered not on the cooling tube in the absorber, that is leading to mal-function of absorber. Also by sloping road, the free surface of solution in the generator and absorber causes mixing of the refrigerant and LiBr solution. To solve the problems, we used hydrophobic flat sheet membrane. Membrane is a porous media that has microscale porous and used for filtration to separate specific substances. By the hydrophobicity of the membrane, the LiBr solution can not penetrate the pores of the membrane. Only vapor, however, can penetrate the pores. That means the membrane can separate the working fluids and vapor refrigerant. By using the membrane for all the components of absorption refrigeration system, the free surface of working fluid is eliminated and the mixing of fluids does not occur by the sloping road. To reduce volume of components, we provide the design of combined generator-condenser and absorber-evaporator using the membranes. In this study, we focused on the theoretical models for heat and mass transfer in membrane based combined unit, and evaluated the performance. Then, we constructed an experimental apparatus using flat membranes and measured the performance.