The ornamental design for a heatexchangerfin, as shown and described.
FIG. 1 is a perspective view of our new design for a heat exchanger fin installed with an array of heat exchanger fins in a heat exchanger for a tankless water heater;
FIG. 2 is a top front perspective view of our new design for a heat exchanger fin;
FIG. 3 is a bottom back perspective view thereof;
FIG. 4 is a left elevation view thereof;
FIG. 5 is a right elevation view thereof;
FIG. 6 is a front elevation view thereof;
FIG. 7 is a back elevation view thereof;
FIG. 8 is a top plan view thereof; and,
FIG. 9 is a bottom view thereof.
The broken lines shown in the figures illustrate the environment in which the heat exchange fin is installed and form no part of the claimed design.