Comparison of the Membrane-based Desorber and Plate Heat Exchanger Desorber for Solar Assisted Absorption Refrigeration Systems

The Absorption Refrigeration System (ARS) is a type of cooling system that uses non-toxic, non-volatile, and nonflammable working fluids. The system includes a pump and a heat exchanger for the molten solution, in addition to evaporator and condenser components found in a vapor compression refrigeration cycle. Instead of using a compressor, a thermal mechanism such as solar or geothermal energy is utilized for circulation, resulting in significant energy savings. Although generally it is used in large industrial applications, the use of membrane technology in the absorber and/or desorber makes it suitable for residential applications due to the large area-to-volume ratios of the resulting components. In this study, the numerical investigation of the membrane-based desorber, which is known to have the highest COP for the ARS, is performed. Working fluid is H₂O–LiBr solution. The pore diameter of microporous polytetraphluoroethylene (PTFE) membrane is 0.45 μm and thickness is 200 μm that is used to separate the solution from the vapour. The results for two type desorbers obtained for hot water and solution heat transfer coefficients, COP, volumetric cooling effect and cooling power are provided and compared to each other.