Patent ID: 7073572

Claim:
A flooded shell and tube evaporator, comprising: a) a shell having an inlet and an outlet and having a first end and a second end; b) a plurality of tubes located in the shell and extending between the first and second ends, the tubes forming a path through the shell, the path comprising at least one pass through the shell; c) supports that position the tubes within the shell, the shell having a first portion and a second portion, the second portion located above the first portion, the first and second portions being flooded with refrigerant; d) the plurality of tubes comprising at least two types, with a first type of tube being located in the first portion and a second type of tube being located in the second portion; e) the first portion having a mode of heat transfer that is different from the mode of heat transfer in the second portion, the first and second type of tubes having heat transfer characteristics suitable for the heat transfer of the respective first and second portions, wherein the heat transfer characteristics of the first type of tube is different than the heat transfer characteristics of the second type of tube; f) the plurality of tubes further comprising a third type of tube having a third heat exchange efficiency that is less than the first heat exchange efficiency and greater than the second heat exchange efficiency, the third type of tubes located between the first and second type of tubes.