Crystallization Equation for determining working zone of LiBr in Vapour Absorption Refrigeration Systems

Abstract: Lithium bromide-water (LiBr-H₂O) absorption refrigeration systems (VARS) are widely used for cooling applications due to their ability to operate on low-grade energy sources. However, a major operational limitation is *crystallization*, which occurs when the solution becomes supersaturated with LiBr. Crystallization can block system components, reduce efficiency, and lead to system failure. This paper presents a thermodynamic analysis of the crystallization phenomenon, supported by simulation results using Engineering Equation Solver (EES). A crystallization condition equation is derived, and a crystallization curve relating generator and absorber temperatures is formulated to define the safe working zone of the system.

Keywords: Crystallization Boundary, Lithium Bromide (LiBr), Working Concentration Zone, Vapour Absorption Refrigeration System (VARS).