High performance louvered fin for heat exchanger

1 . A flat tube heat exchanger comprising:

at least one header;

a plurality of spaced apart tubes in fluid communication with said header; and

a plurality of fins disposed between said tubes, said fins further comprising:

a base wall having a longitudinal axis, a first end, a second end, and a middle portion;

at least one turnaround rib disposed in the middle portion of the base wall;

a plurality of spaced apart entrance louvers disposed between the first end of the base wall and the turnaround rib, the entrance louvers having a first edge and a second edge, a width of each of the entrance louvers defined as a distance between the first edge of each of the entrance louvers and the second edge of each of the entrance louvers, wherein the width of at least one of the entrance louvers is greater than the width of a remainder of the entrance louvers; and

a plurality of spaced apart exit louvers disposed between the turnaround rib and the second end of the base wall, the exit louvers having a first edge and a second edge, a width of each of the exit louvers defined as a distance between the first edge of each of the exit louvers and the second edge of each of the exit louvers, wherein the width of at least one of the exit louvers is greater that the width of a remainder of the exit louvers.

2 . The heat exchanger according to claim 1 , wherein each of the entrance louvers is disposed at a predetermined angle in respect of the longitudinal axis of the base wall, the predetermined angle decreasing for the entrance louvers moving from the first end of the base wall to the turnaround rib.

3 . The heat exchanger according to claim 2 , wherein each of the exit louvers is disposed at a predetermined angle in respect of the longitudinal axis of the base wall, the predetermined angle decreasing for the exit louvers moving from the turnaround rib to the second end of the base wall.

4 . The heat exchanger according to claim 1 , wherein the width of each of the entrance louvers increases moving from the first end of the base wall to the middle portion of the base wall.

5 . The heat exchanger according to claim 1 , wherein the width of each of the exit louvers decreases moving from the middle portion of the base wall to the second end of the base wall.

6 . The heat exchanger according to claim 1 , wherein at least one of the entrance louvers includes a first convex curved surface extending between the first edge and the second edge and a second convex curved surface extending between the first edge and the second edge.

7 . The heat exchanger according to claim 1 , wherein at least one of the exit louvers includes a first convex curved surface extending between the first edge and the second edge and a second convex curved surface extending between the first edge and the second edge.

8 . The heat exchanger according to claim 1 , wherein at least one of said entrance louvers and said exit louvers includes a first bend and a second bend formed between the first edge and the second edge.

9 . A high performance heat exchanger fin comprising:

a base wall having a first end, a second end, and a middle portion;

at least one turnaround rib disposed in the middle portion of said base wall;

a plurality of spaced apart entrance louvers having a longitudinal axis, a first edge, and a second edge, said entrance louvers disposed between the first end of said base wall and said turnaround rib, a width of each of said entrance louvers defined as a distance between the first edge and the second edge, wherein the width of said entrance louvers increases moving in a direction from the first end to the second end of said base wall, each of said entrance louvers disposed at a predetermined angle in respect of the longitudinal axis of said entrance louver, the predetermined angle decreasing for at least one of said entrance louvers moving in a direction from the first end to the second end of said base wall; and

a plurality of spaced apart exit louvers having a longitudinal axis, a first edge, and a second edge, said exit louvers disposed between said turnaround rib and the second end of said base wall, a width of each of said exit louvers defined as a distance between the first edge and the second edge, wherein the width of said exit louvers decreases moving in a direction from the first end to the second end of said base wall, each of said exit louvers disposed at a predetermined angle in respect of the longitudinal axis of said base exit louvers, the predetermined angle decreasing for at least one of said exit louvers moving in a direction from the first end to the second end of said base wall.

10 . The heat exchanger fin according to claim 9 , wherein said entrance louvers and said exit louvers include a first convex curved surface extending between the first edge and the second edge and a second convex curved surface extending between the first edge and the second edge.

11 . The heat exchanger fin according to claim 9 , wherein said entrance louvers and said exit louvers include a first bend and a second bend formed between the first edge and the second edge.

12 . The heat exchanger fin according to claim 9 , wherein the first edges of said entrance louvers are maintained substantially in a single plane, and the second edges of the entrance louvers are maintained substantially in a single plane.

13 . The heat exchanger fin according to claim 9 , wherein the first edges of said exit louvers are maintained substantially in a single plane, and the second edges of the exit louvers are maintained substantially in a single plane.

14 . A high performance heat exchanger fin comprising:

a base wall having a first end, a second end, and a middle portion, said base wall having a first longitudinal axis extending from the first end to the middle portion and a second longitudinal axis extending from the middle portion to the second end, whereby the first longitudinal axis and the second longitudinal axis are non-linear;

at least one turnaround rib disposed in the middle portion of said base wall;

a plurality of spaced apart entrance louvers having a first edge and a second edge, said entrance louvers disposed between the first end of said base wall and said turnaround rib, a width of each of said entrance louvers defined as a distance between the first edge and the second edge, wherein the width of said entrance louvers increases moving in a direction from the first end to the second end of said base wall; and

a plurality of spaced apart exit louvers having a first edge and a second edge, said exit louvers disposed between said turnaround rib and the second end of said base wall, a width of each of said exit louvers defined as a distance between the first edge and the second edge, wherein the width of said exit louvers decreases moving in a direction from the first end to the second end of said base wall.

15 . The heat exchanger fin according to claim 14 , wherein at least one of said entrance louvers includes a first convex curved surface extending between the first edge and the second edge and a second convex curved surface extending between the first edge and the second edge, and wherein at least one of said exit louvers includes a first convex curved surface extending between the first edge and the second edge and a second convex curved surface extending between the first edge and the second edge.

16 . The heat exchanger fin according to claim 15 , wherein the at least one of said entrance louvers and said exit louvers is generally football shaped in cross section.

17 . The heat exchanger fin according to claim 14 , wherein at least one of said entrance louvers includes a first bend and a second bend formed between the first edge and the second edge, and at least one of said exit louvers includes a first bend and a second bend formed between the first edge and the second edge.

18 . The heat exchanger fin according to claim 17 , wherein the at least one of said entrance louvers and said exit louvers is generally S-shaped in cross section.

19 . The heat exchanger fin according to claim 14 , wherein the first edges of said entrance louvers are maintained substantially in a single plane, the second edges of said entrance louvers are maintained substantially in a single plane, the first edges of said exit louvers are maintained substantially in a single plane, and the second edges of said exit louvers are maintained substantially in a single plane.

20 . The heat exchanger fin according to claim 14 , wherein each of said entrance louvers is disposed at a predetermined angle in respect of the first longitudinal axis, the predetermined angle decreasing for said entrance louvers moving from the first end of said base wall to said turnaround rib, and each of said exit louvers is disposed at a predetermined angle in respect of the second longitudinal axis, the predetermined angle decreasing for said exit louvers moving from said turnaround rib to the second end of said base wall.