1. One or more refrigeration condensing units, comprised or a hermetic or semi-hermetic compressor and air-cooled or water-cooled condenser.
2. The water / ice storage tank, which serves as a large cooling water reservoir / holding tank, and contains the submerged evaporator coils / ice-building plates.
3. One or more water recirculating pumps, for delivering chilled water supply (and warm water return — back to the Storage Tank).
4. Operating controls, including special Ice Bank Control, for automatically turning the condensing unit on and off.
5. AC power source.
6. Chilled-water supply piping and warm-water return piping, for recirculating water to and from the machinery or equipment to be cooled.

More on Ice Chillers:
Overview & Photos
Operational Background
 

recirculated water = water cost savings

off-peak electrical use = energy cost savings