What role does the expansion valve play in a refrigeration cycle?

The expansion valve plays a critical role in the refrigeration cycle by decreasing the refrigerant pressure as it exits the valve. This reduction in pressure is essential because it allows the refrigerant to expand and cool before entering the evaporator coil. When the refrigerant flows through the expansion valve, its pressure drops significantly, which also results in a decrease in temperature. This low-temperature, low-pressure refrigerant is then able to absorb heat from the environment inside the evaporator, facilitating the cooling process.

The functionality of the expansion valve is key to the overall efficiency of the refrigeration system. By creating a significant pressure difference, it ensures that the refrigerant can readily absorb heat, transitioning from a liquid state to a vapor state, which is crucial for the heat exchange process that occurs in the evaporator. The ability of the expansion valve to control the flow and pressure of the refrigerant significantly impacts the performance and efficiency of the refrigeration cycle. This is why the option indicating that it decreases the refrigerant pressure is indeed the correct choice.