Larger buildings, process facilities, and other applications use chilled water cooling systems for its many advantages, including refrigerant and maintenance containment, energy efficiency, and lower first cost.
While the chiller is typically the most expensive, most energy consuming, and most visible part of the system, other key components include chilled and condenser water pumps, cooling towers, heat exchangers, and hydronic specialties such as water pressure regulators, air separators, and chemical feed pots. Controls are also critical to the system because they operate water valves, control setpoints, and schedule equipment. All these components and capabilities support the delivery of cooling water to the airside or process loads and carry unwanted heat to sources of heat rejection. This article will focus on maintaining these components “beyond the flange,” which are found in most typical building comfort cooling applications.
Mechanical water chillers are available in many types and configurations typically categorized by compressor type — reciprocating, scroll, screw, and centrifugal. These types are further segmented by air-cooled or water-cooled designations. Most air-cooled chillers are packaged units, which come as complete assemblies. Some air-cooled chillers are even available with integral pumping packages. Water-cooled chillers have condensers that are cooled by cooling towers or other sources to reject the heat. This article will focus on the water-cooled chiller system.