In an ammonia absorption refrigeration system, what is used as the absorbent?

In an ammonia absorption refrigeration system, ammonia itself serves as the refrigerant, while water acts as the absorbent. In the context of absorption refrigeration, the absorbent is the substance that picks up or absorbs the refrigerant vapor. Water is an efficient absorbent for ammonia, allowing the system to operate effectively.

The ammonia absorption refrigeration cycle operates by having ammonia vapor pass through a condenser, where it is condensed to a liquid state. This liquid ammonia is then introduced to the absorber, where it is absorbed into the water, forming a concentrated solution of ammonia. This solution is then pumped to a generator, where heat is applied to separate the ammonia from the water, regenerating the refrigerant.

The mention of lithium bromide, Freon, or ammonia itself as absorbents is not applicable here. Lithium bromide is typically used in lithium bromide absorption chillers, which do not involve ammonia, and Freon (a brand name for various halocarbon refrigerants) does not apply to ammonia absorption refrigeration systems. Therefore, the role of the absorbent is clearly defined as water in this context.