In an air conditioning refrigeration system, the functions of the stainless steel capillary coil tube need to be comprehensively understood from two concepts — "capillary tube" and "coil", together with the properties of stainless steel material. It performs the following core functions in the refrigeration system:

1. Core function of capillary tube: Throttling and pressure reduction

In the air-conditioning refrigeration cycle, the capillary tube is a critical throttling device. When high-pressure liquid refrigerant flows through the capillary tube with an extremely small inner diameter (typically ranging from 0.6 to 2 mm), significant pressure drop occurs due to flow resistance. This throttling effect sharply reduces the pressure and temperature of the refrigerant, turning it into a low-temperature and low-pressure gas-liquid mixture. This creates the prerequisite for low-temperature boiling and heat absorption inside the subsequent evaporator.

2. Advantages of coil configuration: Compact structure and enhanced heat transfer

Designing capillary tubes or heat exchange tubes in a spiral coil form is mainly to accommodate space constraints and improve heat transfer efficiency:

• Compact structure: The coil layout arranges a longer pipeline within a tiny space and provides a larger heat exchange area, which is well suited for small refrigeration equipment or micro heat exchangers with limited space.

• Enhanced heat transfer: When fluid flows inside the spiral pipeline, it continuously changes direction. This motion effectively disturbs the fluid boundary layer and generates secondary turbulence, enabling more sufficient heat exchange and greatly improving heat transfer efficiency.