How does a capillary tube function in a refrigeration system?

A capillary tube functions primarily as a metering device within a refrigeration system. Its primary role is to control the flow of refrigerant from the high-pressure side of the system to the low-pressure side. By doing so, it allows the refrigerant to expand, which is essential for the cooling process.

When the refrigerant flows through the capillary tube, it experiences a drop in pressure as it moves from a higher pressure area to a lower pressure area. This drop in pressure causes the refrigerant to partially vaporize, which is an essential part of the refrigeration cycle. The capillary tube allows for a precise amount of refrigerant to enter the evaporator, ensuring that the system operates efficiently.

In contrast, the other options do not accurately describe the function of a capillary tube. A heat exchanger is a separate component designed to transfer heat between substances without mixing them. Compressing the refrigerant is the primary function of the compressor, not the capillary tube. Lastly, while the capillary tube has an indirect effect on temperature regulation by controlling refrigerant flow, it does not directly regulate temperature within the cabinet itself. Therefore, its role as a metering device is crucial for the effective operation of the refrigeration system.