What is the purpose of the expansion valve in an air conditioning system?

The purpose of the expansion valve in an air conditioning system is to regulate refrigerant flow. The expansion valve acts as a control device that reduces the pressure of the refrigerant as it passes from the high-pressure side of the system to the low-pressure side. This pressure drop allows the refrigerant to expand and cool as it enters the evaporator coil. By regulating the flow of refrigerant, the expansion valve maintains the optimal operating conditions for the evaporator, ensuring efficient heat absorption from the indoor air. This process is crucial for the overall cooling effectiveness of the air conditioning system.

In contrast, while the other options involve aspects of refrigerant management, they do not describe the primary function of the expansion valve. Increasing refrigerant pressure is typically the role of the compressor, cooling the refrigerant is done in the evaporator or condenser depending on the cycle stage, and storing excess refrigerant is not a function served by any component in the system but rather is managed through overall system design and sizing.