What is the role of the expansion valve in an HVAC system?

The expansion valve plays a crucial role in regulating the flow of refrigerant entering the evaporator within an HVAC system. Its primary function is to reduce the pressure of the refrigerant, allowing it to expand and cool before it enters the evaporator coil. This process is essential because it prepares the refrigerant to absorb heat efficiently from the indoor air, facilitating the cooling process.

By controlling the refrigerant flow, the expansion valve ensures that the evaporator receives the optimal amount of refrigerant for effective heat exchange. This regulation is vital for maintaining system efficiency and preventing issues such as refrigerant starvation or flooding in the evaporator coils, which could lead to poor performance or damage.

Other options do not accurately describe the function of the expansion valve; it does not compress the refrigerant, convert it from liquid to gas, or release heat. Instead, it precisely manages the transition from high-pressure liquid refrigerant to lower-pressure gas, making it an essential component of the refrigeration cycle.