What do the flooded and recirculated system have in common?

The correct choice highlights that in both flooded and recirculated systems, the flash/track gas does not pass through the evaporator, and the refrigerant is saturated as it exits the evaporator under normal operating conditions. This is significant because both systems utilize refrigerant management strategies that aim to optimize heat exchange while preventing the issues that could arise from introducing superheated gas prematurely.

In flooded systems, the evaporator is filled with liquid refrigerant, and only when conditions allow does some of this liquid boil off into vapor, creating a mixture of liquid and vapor within the evaporator. This ensures that when the refrigerant exits the evaporator, it is in a saturated state, which is essential for effective operation as it indicates that the liquid has absorbed enough heat.

In recirculated systems, a similar principle applies but with variations in flow and mixture control. Here, the focus also remains on ensuring that the refrigerant is in a saturated state as it exits, providing optimal efficiency and reducing the chances of compressor damage due to the presence of liquid refrigerant.

Understanding this concept is critical, as it addresses the design and operational goals of the systems, especially concerning how they manage refrigerant state and phase transitions throughout the cooling cycle.