Lithium-Bromide is used in absorption systems as:

• A. A salt solution
• B. An absorbent
• C. A solution that creates a pressure difference
• D. All of the above

Answer: (D)

Lithium bromide works as the absorbent in absorption cooling systems because it forms a highly hygroscopic salt solution with water. This LiBr-water solution readily absorbs water vapor from the refrigerant loop, making it an effective absorber. As it absorbs vapor, the water’s vapor pressure in the evaporator is lowered, creating a pressure difference between the evaporator and absorber that drives vapor toward the absorber. In operation, the absorbed water-laden LiBr solution is heated to release the water and regenerate a lean LiBr solution for another cycle. So lithium bromide is used as a salt solution, as the absorbent, and because the absorption process establishes the necessary pressure difference—all of which are true.