In addition to refrigerant, what other compound is used by absorption systems to operate?

Absorption systems, commonly found in refrigeration and air conditioning applications, typically operate using two key components: a refrigerant and an absorbent. The absorbent serves to absorb the refrigerant vapor, creating a solution that, when heated, will release the refrigerant and allow the cycle to continue.

In these systems, the absorbent is crucial as it helps to maintain the cycle of evaporation and condensation without the need for a mechanical compressor, which is a distinct feature of absorption systems compared to vapor-compression systems. A common example of an absorbent is water in ammonia absorption systems or lithium bromide in water systems. The role of the absorbent is not only to facilitate the refrigerant's cycling but also to enhance the efficiency of the absorption process.

The other options, while related to cooling systems, do not fit the specific role that an absorbent plays in the operation of absorption refrigeration. For instance, a liquid coolant refers to a substance used to transfer heat away, which does not absorb the refrigerant itself. A heat exchange fluid is essential for transferring heat but does not take on the role of absorbing refrigerants directly. A pressure stabilizer might be involved in maintaining system pressures but is not directly part of the absorption process.

Overall, the