PACKAGED WATER CHILLERS.

Liquid chiller packages are used in many plants to cool water, glycol mixtures, or brines for central station air conditioning systems, refrigeration applications, or process cooling. The temperature of the chilled liquid required by the operation determines the type of cooling medium selected. About 90 percent of the chillers used in industry provide water-based liquids for central station air conditioning systems; this article is confined to that type of equipment. The most common chiller systems use reciprocating, centrifugal, or screw compressors; air, water, or evaporative condensers; and flooded or direct expansion evaporators. Another approach to providing chilled water is the absorption cycle, which uses water as the refrigerant instead of halocarbons or ammonia. Characteristics, applications and maintenance requirements for each of these systems are discussed.