LiBrWasser

LiBrWasser is a term used for an aqueous solution of lithium bromide (LiBr) in water. This solution serves as the absorbent in many absorption cooling and heating systems, where water acts as the refrigerant in the cycle. The LiBr-rich solution absorbs water vapor released from the evaporator, allowing the system to transfer heat without mechanical compression.

Properties of LiBrWasser include high hygroscopicity and strong affinity for water, which enables efficient absorption of water vapor at relatively low vapor pressures. The solution is typically highly soluble and forms clear, colorless mixtures. A practical challenge is the tendency of the solution to crystallize when cooling or becoming too concentrated; crystallization can impair heat transfer and block flow paths. Materials compatibility is important, as concentrated LiBr solutions can be corrosive to some metals, necessitating the use of suitable construction materials such as stainless steels or nickel-based alloys.

In operation, LiBrWasser is circulated between an absorber and a generator (desorber). In the generator, heat causes water to desorb from the solution; the vapor then condenses and is piped to the evaporator, where it absorbs heat from the cooled space. The absorbed water returns to the LiBr solution in the absorber, releasing heat to the surroundings during the absorption process. This cycle allows cooling or heat pumping using low-grade thermal energy, often from waste heat or solar sources.

Applications include air-conditioning and process cooling for buildings and industries. Advantages of LiBrWasser systems include quiet operation and the use of heat sources other than electricity, but they require careful control of solution concentration and robust materials to mitigate crystallization and corrosion risks.