What happens to the refrigerant as it moves through a capillary tube?

As the refrigerant moves through a capillary tube, it undergoes an expansion process that results in a drop in pressure. In this constrained environment of the capillary tube, the refrigerant is pushed through a narrow passage, which is designed to restrict its flow. This restriction leads to a significant decrease in pressure as the refrigerant moves from a high-pressure area to a low-pressure area.

Additionally, as the refrigerant expands, its temperature typically decreases, which is linked to the principles of thermodynamics regarding expansion in a confined space. This behavior is a critical aspect of refrigeration systems, enabling the refrigerant to absorb heat from the surrounding environment as it continues on to the evaporator, ultimately playing a key role in the cooling process of air conditioning systems. In summary, the expansion and resultant drop in pressure of the refrigerant as it passes through a capillary tube is a fundamental aspect of how cooling systems operate efficiently.