What is the role of the expansion device in a refrigeration system?

The expansion device plays a crucial role in a refrigeration system by controlling the flow and reducing the pressure of the refrigerant as it moves from the high-pressure side of the system to the low-pressure side. This is essential for the refrigeration cycle, as it allows the refrigerant to expand and cool before entering the evaporator.

When the refrigerant passes through the expansion device, its pressure drops significantly. This drop in pressure causes the refrigerant to experience a phase change from a liquid to a vapor, absorbing heat in the process. This is the foundation of how refrigeration works, as the low-pressure vapor then enters the evaporator, where it absorbs heat from the environment being cooled.

Choosing this answer reflects an understanding of how the refrigeration cycle operates, particularly the essential functions of pressure regulation and flow control, which are vital for efficient cooling.