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Refrigeration Equipment | Up
Utilitiesman Basic Volume 02 - Manual for electric, plumbing, water and other utilities | Next
Single Door Fresh Food Refrigerator |
supplies requiring temperatures between 30°F and
45°F. Standard-size units most frequently used are
those with storage capacities between 15 and 85 cubic
feet. Figure 6-34 shows a typical reach-in refrigerator
with a remote (detached) condensing unit.
Exterior finishes for reach-in refrigerators are
usually of stainless steel, aluminum, or vinyl, while the
interior finishes are usually metal or plastic, and the
refrigerator cabinet is insulated with board or batten
type polystyrene or urethane. Reach-in refrigerators
are normally self-contained, with an air-cooled
condenser, but in larger refrigerators, with remote
condensers, water-cooled condensers are sometimes
used. A typical self-contained unit is shown in figure
6-35. The evaporator is mounted in the center of the
upper portion of the food compartment. In operation,
warm air is drawn by the fan into the upper part of the
unit cooler, where it passes over the evaporator coils, is
cooled, and then is discharged at the bottom of the
cooler. The air then passes up through the interior and
around the contents of the refrigerator. The cycle is
completed when the air again enters the evaporator.
The low-pressure control is set to operate the
evaporator on a self-defrosting cycle, and temperature
is thus control led. Another type of control system uses
both temperature and low-pressure control or defrost
on each cycle.
The evaporator fan is wired for
continuous operation within the cabinet.
Figure 6-35.—A self-contained reach-in refrigerator.
Evaporators in reach-in refrigerators are generally
the unit cooler type with dry coils (fig. 6-36). In
smaller capacity refrigerators, ice-making coils,
similar to those used in domestic refrigerators, are
often used as well as straight gravity coils. R-12 and
R-502 are normally used in these units.
WALK-IN REFRIGERATORS
Walk-in refrigerators are normally larger than
reach-in types and are either built-in or prefabricated
sectional walk-in units. They are made in two
Figure 6-36.—A. Unit cooler in a reach-in refrigerator; B.
Dome cooler in a reach-in refrigerator.
6-24
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