Through which component is refrigerant added to a centrifugal machine?

Refrigerant is added to a centrifugal machine through the evaporator charging valve. This is because the evaporator is where the refrigerant absorbs heat and changes from a liquid to a vapor, playing a crucial role in the refrigeration cycle. When refrigerant needs to be added, it is usually introduced into the system at the evaporator because this component is designed to handle the refrigerant in its low-pressure state, ensuring that the system operates efficiently and safely.

In contrast, the condenser charging valve is used for managing refrigerant in the higher-pressure side of the system. The expansion valve, while important for regulating the flow of refrigerant into the evaporator, is not typically where you would add refrigerant directly. Lastly, adding refrigerant through the compressor would not be appropriate or effective, as the compressor is primarily meant for compressing vapor rather than introducing refrigerant into the system.