We claim the ornamental design for a refrigeration unit, as shown and described.
FIG. 1 is a front perspective view a refrigeration unit embodying the invention.
FIG. 2 is a front view of the refrigeration unit of FIG. 1.
FIG. 3 is a top view of the refrigeration unit of FIG. 1.
FIG. 4 is a bottom view of the refrigeration unit of FIG. 1.
FIG. 5 is a right side view of the refrigeration unit of FIG. 1.
FIG. 6 is a left side view of the refrigeration unit of FIG. 1.
FIG. 7 is a front perspective view a refrigeration unit embodying the invention.
FIG. 8 is a front view of the refrigeration unit of FIG. 7.
FIG. 9 is a top view of the refrigeration unit of FIG. 7.
FIG. 10 is a bottom view of the refrigeration unit of FIG. 7.
FIG. 11 is a right side view of the refrigeration unit of FIG. 7; and,
FIG. 12 is a left side view of the refrigeration unit of FIG. 7.
The portions of the refrigeration unit shown in broken lines are included for the purpose of illustrating environment and form no part of the claimed design.