What is typically controlled by the expansion device in the refrigeration cycle?

The expansion device in a refrigeration cycle primarily controls the flow of refrigerant. This device is responsible for regulating the amount of refrigerant that flows into the evaporator, where the refrigerant absorbs heat and evaporates. By controlling this flow, the expansion device ensures that the evaporator operates efficiently, allowing for optimal heat exchange and maintaining the necessary pressure differential between the high-pressure and low-pressure sides of the system.

When the expansion device opens or closes, it adjusts the refrigerant's passage, which directly impacts the cooling capacity of the system. If too much refrigerant flows into the evaporator, the system can flood, leading to inefficiencies and potential damage. Conversely, if too little refrigerant is allowed, it can cause the evaporator to become starved, leading to inadequate cooling and increased stress on the compressor.

While the other options pertain to important aspects of the refrigeration cycle, they are not directly controlled by the expansion device. For example, refrigerant pressure is influenced by various components in the system, including the compressor and condenser, rather than being directly managed by the expansion device itself.