Heat exchanger tube and method for manufacturing the same

A heat exchanger tube adapted for use with at least one device selected from the group consisting of an absorber, a regenerator and an evaporator of an absorption refrigerator, said heat exchanger tube effecting a heat exchange between a fluid inside the heat exchanger tube and a liquid flowing outside the heat exchanger tube, and said heat exchanger tube comprising:

• a first kind of spiral grooves;
• and
• a second kind of spiral grooves,
• wherein each of said first and second kinds of spiral grooves are formed on an outer surface of the heat exchanger tube,
• wherein a twisting direction of said first kind of spiral grooves relative to an axis of said heat exchanger tube is the same as a twisting direction of said second kind of spiral grooves,
• wherein a helix angle of said first kind of spiral grooves is larger than a helix angle of said second kind of spiral grooves, said helix angle of said first kind of spiral grooves falling within a range of 3.degree. to 80.degree. relative to the axis of said heat exchanger tube and said helix angle of said second kind of spiral grooves falling within a range of 3.degree. to 30.degree. relative to the axis of said heat exchanger tube, and wherein a groove depth of said first kind of spiral grooves is smaller than a groove death of said second kind of spiral grooves, said groove depth of said first kind of spiral grooves falling within a range of 0.1 to 0.5 mm and said groove depth of said second kind of spiral grooves falling within a range of 0.3 to 0.85 mm.