Heat transfer tubes, including methods of fabrication and use thereof

A method of fabricating a heat transfer tube having an inner surface and an outer surface, the method comprising:

• (a) forming a plurality of fins on the outer surface of the tube, wherein a plurality of channels extend between adjacent fins;
• (b) notching at least some of the fins to form a plurality of notches, wherein a first nucleate boiling cavity is at least partially defined by a channel and a notch;
• and
• (c) bending over or flattening at least a portion of a notched fin to form a second nucleate boiling cavity in communication with the first nucleate boiling cavity.

An improved refrigerant evaporator, comprising:

• a. a shell;
• b. a refrigerant within the shell;
• and
• c. at least one heat transfer tube within the shell and in contact with the refrigerant, the heat transfer tube comprising:
• i. an outer surface, said outer surface comprising a plurality of fins with channels extending between adjacent fins, wherein notches are formed in the fins;
• and
• ii. at least one dual cavity nucleate boiling pore formed at the intersection of a notch and a channel, wherein the nucleate boiling pore comprises a first nucleate boiling cavity and a second nucleate boiling cavity, wherein the first nucleate boiling cavity is at least partially defined by at least a portion of the notch extending at least partially over the channel and wherein the second nucleate boiling cavity is at least partially defined by at least a portion of a notched fin extending at least partially over the notch.