What is the main function of a drier in a refrigeration system?

The primary function of a drier in a refrigeration system is to remove moisture from the refrigerant. Moisture can be harmful within a refrigeration system as it can cause corrosion, reduce the efficiency of the refrigerant, and lead to the formation of ice, which can block refrigerant flow. The drier ensures that the refrigerant is kept dry, allowing it to function properly and maintain optimal performance throughout the system.

In practice, the drier contains a desiccant that absorbs moisture, helping to maintain the purity of the refrigerant. This is crucial for sustaining efficient operation, extending the life of the components in the system, and preventing potential failures.

The other functions listed do not pertain to the role of the drier. Circulating the refrigerant efficiently falls under the responsibilities of the compressor and the expansion valve. Increasing the system's pressure is primarily the job of the compressor as well. Cooling air before it enters the evaporator is more about the role of the evaporator itself and the overall heat exchange taking place in the refrigeration cycle. Hence, the drier's specific task is focused on moisture removal, making that answer key to understanding its importance in refrigeration systems.