During the refrigeration cycle, what is the function of the compressor?

The function of the compressor in the refrigeration cycle is to increase the pressure of the refrigerant. When the refrigerant enters the compressor, it is typically in a low-pressure gas state. The compressor compresses this gas, which significantly raises its pressure and temperature.

By increasing the pressure, the refrigerant is then able to flow into the condenser, where it can release heat and change from a gas to a liquid state. This compression process is crucial for maintaining the refrigerant cycle, as it enables the refrigerant to absorb heat from the evaporator during its passage through the system, which is essential for the cooling process to occur.

The other functions listed in the options—evaporating, condensing, and circulating the refrigerant—are performed by other components in the refrigeration system, such as the evaporator and condenser, but not by the compressor itself. Thus, the key role of raising the refrigerant's pressure distinguishes the compressor's function clearly within the cycle.