2. Fundamental aspects

2.1 Water-lithium bromide diagrams

Water is the refrigerant, while LiBr salt, solid in its anhydrous state, is the absorbent used in hydrated solution in the liquid state. However, depending on water content and temperature, salt crystallization may occur, which must be avoided in the process. The fact that the LiBr salt is a solid is an important point, as its vapour pressure is almost zero and negligible compared with that of water vapour, so that the vapour pressure of the solution is that of water vapour only.

At liquid-vapor equilibrium, the H ₂ O-LiBr system is divariant (the Gibbs phase rule of variance V is :