What is the condition of the refrigerant as it leaves the evaporator?

As the refrigerant leaves the evaporator, it is primarily in the form of a low-pressure vapor. This happens because the evaporator's function is to absorb heat from the cabin air or other sources, which causes the refrigerant to evaporate. In this process, the refrigerant transitions from a liquid state to a gaseous state, absorbing heat during evaporation.

By the time the refrigerant exits the evaporator, it has effectively absorbed heat and therefore has a lower pressure compared to when it was in the liquid state. This low-pressure vapor is then routed to the compressor, where it will be pressurized before entering the condenser. Understanding this cycle is crucial in the operation of a cabin atmosphere control system, as it directly affects the efficiency and temperature control within the aircraft cabin.