Which type of refrigerant is primarily used in absorption systems?

Lithium bromide is primarily used in absorption systems due to its effective hygroscopic properties, which enable it to attract and hold water vapor. In absorption refrigeration, a small quantity of water is the refrigerant, and lithium bromide acts as the absorbent. This combination allows for the efficient transfer of heat during the refrigeration cycle.

Lithium bromide solutions are particularly utilized in cooling applications such as large commercial air conditioning systems where cooling loads can be significant. Its ability to operate at lower pressure levels also contributes to the efficiency of the absorption process, making it ideal for this application.

Other refrigerants like Freon (CFCs or HCFCs) are more commonly used in vapor-compression systems rather than absorption systems. Ammonia is generally employed as a refrigerant in industrial applications, and while carbon dioxide is gaining traction for its environmental benefits, it is not the primary choice for absorption systems. Thus, lithium bromide stands out as the primary absorbent in such systems.