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

The primary function of a compressor in a refrigeration system is to compress the refrigerant gas. By doing this, the compressor increases the pressure and temperature of the refrigerant, preparing it for the next stage of the refrigeration cycle. This process is crucial because it allows the refrigerant to move through the system effectively, promoting heat exchange and allowing the refrigeration process to work efficiently.

When the refrigerant is compressed, its density increases, enabling it to absorb and release heat more effectively as it moves through the evaporator and condenser, which are essential components of a refrigeration system. The compressor essentially drives the refrigeration cycle, ensuring the consistent circulation of refrigerant and maintaining the desired cooling effect within the system.

The other options focus on various functions that are not directly related to the compressor's vital role. For instance, the notion of cooling the refrigerant is not a function of the compressor; instead, this task is carried out by the evaporator. Similarly, circulating air is managed by fans, and expanding pressure relates to the expansion valve rather than the compressor itself. Therefore, recognizing the compressor's role as the component that compresses refrigerant gas is fundamental to understanding how a refrigeration system operates.