Where does the flash/tax gas go after the expansion valve in all DX systems?

In a direct expansion (DX) refrigeration system, after the expansion valve, the flash/tax gas, which consists of refrigerant that has transitioned from a liquid state to a gas state due to the drop in pressure, moves into the evaporator. This is a crucial phase in the operation of the system.

When the refrigerant passes through the expansion valve, it experiences a significant pressure drop and begins to absorb heat as it enters the evaporator. The presence of the flash gas helps ensure that the refrigerant can efficiently absorb heat from the surrounding environment within the evaporator. The combination of liquid refrigerant and vaporized flash gas allows for effective heat exchange, maximizing the cooling capacity of the system.

This understanding is fundamental to the functioning of DX systems, as it relates directly to the heat absorption process that occurs within the evaporator, which is essential for the refrigeration cycle. Thus, the correct answer highlights the important role that the flash/tax gas plays in the overall operation of DX systems, facilitating efficient thermal exchange.