Page 98 - WaterSense at Work

WaterSense at Work: Best Management Practices for Commercial and Institutional Facilities
Commercial ice machines use refrigeration units to freeze water into ice for cool-
ing or preserving food and other items. Ice machines have become a mainstay in
all types of settings, including restaurants, commercial kitchens, fast food establish-
ments, convenience stores, grocery stores, schools, hotels, hospitals, and laboratories.
Ice machines typically use water for two purposes: cooling the refrigeration unit and
making ice. There are mechanisms to address the efficiency of both aspects.
Because the ice-making process generates a significant amount of
heat, either water or air is used to remove this waste heat from the ice
machine’s refrigeration unit. In the most basic configuration, water-
cooled ice machines pass water through the machine once to cool
it, and then dispose of the single-pass water down the drain. Water-
cooled systems can use less water by recirculating the cooling water
through a chiller or a cooling tower to lower the temperature, return-
ing the water to the machine for reuse. To eliminate using water to
cool the refrigeration unit altogether, air can be used to cool the unit
instead. Air-cooled ice machines use motor-driven fans or centrifugal
blowers to move air through the refrigeration unit to remove heat.
There are three primary types of ice machines: ice-making head units,
self-contained units, and remote condensing units. Ice-making head
units include the ice-making mechanism and the condenser unit in
a single package, and the ice storage bins are sold separately. Self-
contained units have the ice-making mechanism, condenser unit, and
a built-in storage bin in an integral cabinet. These units are typically
small, undercounter units that produce a smaller volume of ice. Re-
mote condensing units are models with the ice-making mechanism
and the condenser unit in a separate section. They transfer the heat generated by the
ice-making process outside the building.
Regardless of how the machine is cooled, all ice machines use water to produce ice.
If a machine were 100 percent water-efficient and wasted no water when produ-
cing ice, the machine would use approximately 12 gallons of water to produce 100
pounds of ice.
However, in order to create ice of acceptable quality, some water is
used and sent down the drain during the process. The amount of water used for the
ice-making process depends upon the facility’s incoming water quality and on the
desired end quality of the ice. Specifically, water is used to rinse ice-making surfaces
and flush minerals that accumulate as water crystallizes into ice.
As ice is formed in the freezing trays, minerals in the water collect on the equipment
and must be rinsed occasionally. Ice machines at facilities with poorer incoming
water quality (i.e., incoming potable water that contains high total dissolved solids
or minerals) will require more frequent rinse cycles. Some ice machines might be set
Commercial Ice Machines
U.S. Environmental Protection Agency (EPA) and U.S. Energy Department’s (DOE’s) ENERGY STAR. Commercial Ice Machines.
Alliance for Water Efficiency (AWE). Ice Machines.
Cubed ice machine