In absorption chillers, usually the crystallization line for lithium bromide and water is very close to
the working concentrations needed for practical LiBr-H2O absorption chillers. If the solution
concentration is too high or the solution temperature is reduced too low, crystallization may occur and
interrupt machine operation. Crystallization must be avoided since the formation of slush in the piping
network over time could form a solid and block the flow. To recover absorber operation after
crystallization occurs is very labor intensive and time consuming [3].
In the past, two principal technical approaches to LiBr absorption design have been used. They
involve: (1) Mechanical design changes, such as very highly efficient heat exchangers, to bring the aircooled
operation within the existing LiBr-H2O crystallization limits. This approach is significantly more
expensive per ton of capacity than the conventional water-cooled LiBr-H2O absorption chillers, and
therefore it is not considered suitable in most applications [4]. (2) The use of chemical additives, such as
2-Ethyl Hexanol, to shift the crystallization line to higher temperatures to allow air-cooled operation with
commercially practical margins of safety from crystallization using conventional heat exchangers.
However, all of the suitable chemicals exhibit negative characteristics that effectively limit their practical
application.