Refrigeration lithium bromide cycle

The ammonia-water absorption system was extensively used until the fifties when the LiBr-water combination became popular. Figure 11-103 shows a simplified ammonia-water absorption cycle. The refrigerant is ammonia, and the absorbent is dilute aqueous solution of ammonia. Ammonia-water systems differ from water-lithium bromide equipment to accommodate major differences Water (here absorbent) is also volatile, so the regeneration of weak water solution to strong water solution is a fractional distillation. Different refrigerant (ammonia) causes different, much higher pressures about 1100-2100 kPa absolute in condenser. 

Absorption Systems. Absorption refrigeration cycles employ a secondary fluid, the absorbent, to absorb the primary fluid, refrigerant vapor, which has been vaporized in the evaporator. The two materials that serve as the refrigerant—absorbent pair must meet a number of requirements however, only two have found extensive commercial use ammonia—water and water—lithium bromide. 

Absorption chillers may operate either a one or two stage absorption refrigeration cycle, using water as the refrigerant (typically inhibited by molybdate) and lithium bromide as the absorbent. Depending on design, heat exchangers may include ... 

Absorption Refrigeration - A system in which a secondary fluid absorbs the refrigerant, releasing heat, then releases the refrigerant and reabsorbs the heat. Ammonia or water is used as the vapor in commercial absorption cycle systems, and water or lithium bromide is the absorber. 

---