Figure 6-40.Storage type of water cooler.
method of installation. Water cooler cabinets have a
sheet metal housing attached to a steel framework. The
condenser and hermetic compressor are located in the
housing base, and the evaporator is located in the
cabinet depending on its type of evaporator, but
normally under the drain basin. Most water coolers use
a heat exchanger or precooler, which precools the fresh
water line to the evaporator, reducing cooling
requirements for the evaporator. A thermostat, which
is manually set and adjusted, is located in the cooler
housing close to the evaporator.
Automatic ice machines, similar to the units
shown in figures 6-41 and 6-42, are often used in
galleys, barracks, gymnasiums, and other public areas.
Ice machines are self-contained, automatic machines,
ranging from a small unit producing 50 pounds of ice
per day to a commercial unit producing 2,400 pounds
of ice per day. The primary difference in the design of
these machines is the evaporator. They automatically
control water feed to the evaporator, freeze the water in
an ice cube mold, heat the mold and empty the ice into a
storage bin, and shut down when the storage bin is full.
Floats and solenoids control water flow, and switches
operate the storing action when ice is made. Electrical
heating elements, hot water, hot gas defrosting, or
mechanical devices remove the ice from the freezing
surfaces depending on the unit. Figures 6-43 and 6-44
show the freezing and defrost cycle of a typical ice
cube machine. In recent years, many companies have
begun to manufacture their units to use HFC R-404a
refrigerant instead of HCFC R-22.
Figure 6-41.Flake or chipped-ice machine.