Which component is primarily responsible for regulating the flow of refrigerant in an R22 system using capillary tubes?

The component that is primarily responsible for regulating the flow of refrigerant in an R22 system using capillary tubes is indeed the capillary tube itself. In systems that utilize capillary tubes, these tubes serve as a flow restriction device, controlling the amount of refrigerant that can enter the evaporator coil.

Capillary tubes have a small diameter and a long length, which creates a pressure drop as refrigerant passes through them. This pressure drop and the inherent design of the capillary tube allow the refrigerant to be metered into the evaporator at a rate that corresponds to the cooling demand of the system. In contrast to expansion valves, which are actively controlled based on temperature and pressure changes, capillary tubes operate passively, responding only to the refrigeration cycle's conditions and the properties of the refrigerant.

The compressor plays a crucial role in circulating refrigerant through the system but does not directly regulate flow; it simply moves the refrigerant from one component to another. The evaporator coil is where the refrigerant absorbs heat to cool the air, but it does not control the refrigerant's flow either. An expansion valve is typically responsible for controlling refrigerant flow in more complex systems but is not utilized in systems with capillary tubes.