The present invention discloses an improved heat transfer tube, an
improved method of formation, and an improved use of such heat transfer
tube. The present invention discloses a boiling tube for a refrigerant
evaporator that provides at least one dual cavity nucleate boiling site.
The present invention further discloses an improved refrigerant
evaporator including at least one such boiling tube, and the method of
making such a boiling tube.