<p>A method of conveying a mixture liquid refrigerant and gaseous refrigerant through an evaporator shell that contains a plurality of heat exchanger tubes, the method including: delivering the mixture of liquid refrigerant and gaseous refrigerant into a bottom portion of the evaporator shell, wherein the mixture upon entering the evaporator shell is at least 90% gaseous refrigerant by volume; at least temporarily trapping the gaseous refrigerant within a gas trap chamber that is between the bottom portion of the evaporator shell and the plurality of heat exchanger tubes; and conveying the liquid refrigerant from the gas trap chamber and directing the liquid refrigerant upward toward the plurality of heat exchanger tubes.</p>
