Which component is primarily responsible for controlling refrigerant flow in a system?

The component that is primarily responsible for controlling refrigerant flow in a system is the expansion valve. This device plays a critical role in regulating the flow and pressure of refrigerant entering the evaporator. The expansion valve reduces the pressure of the refrigerant from the high-pressure side of the system (after leaving the condenser) to the low-pressure side, allowing it to expand and cool as it enters the evaporator.

This regulation is essential because it ensures that the evaporator receives the right amount of refrigerant to change from a liquid state to a gas state, facilitating effective heat absorption and maintaining the efficiency of the refrigeration cycle. Without proper control of the refrigerant flow provided by the expansion valve, the system would either overfeed or underfeed the evaporator, leading to inadequate cooling performance and potential system damage.

The other components, while crucial for the refrigeration cycle, have different primary functions. The condenser's role is to reject heat from the refrigerant, the compressor's job is to compress the refrigerant and circulate it through the system, and the receiver drier functions to filter and store refrigerant while removing moisture. Each component works in harmony, but it is the expansion valve that specifically controls the refrigerant flow into the evaporator.