What is a Chiller?
Liquid chillers often cause confusion to customers assuming it is a specialist section not to be serviced by the average contractor. The simple explanation is that, it is simply a refrigeration system cooling a secondary refrigerant, no more complicated than any other refrigeration circuit.
Air Conditioning Systems
In air conditioning systems, chilled water is typically distributed to heat exchangers, or coils, in air handling units, or other types of terminal devices which cool the air in its respective spaces, and then the chilled water is re-circulated back to the chiller to be cooled again. These cooling coils transfer sensible heat and latent heat from the air to the chilled water, thus cooling and usually dehumidifying the air stream.
CIBSE Guide B2 describes a fan coil unit as "a packaged assembly comprising heating and cooling coil(s), condensate tray collection, circulating fan and filter, all contained in a single housing". The fan recirculates air from the space continuously through the coil(s) either directly or via the void in which the fan coil is located. Fan coil units are far removed from FCUs of only two years ago. Today´s modern fan coil units can include EC (electronically commutated) fans that can provide VAV (Variable Air Volume) capability. Traditional AC fan coil units in horizontal, vertical, cased and chassis forms are also available.
chilled water and a central air handling unit can provide tempered fresh air.
Industrial Applications
In industrial applications, chilled water or other liquid from the chiller is pumped through process or laboratory equipment. Industrial chillers are used for controlled cooling of products, mechanisms and factory machinery in a wide range of industries. They are often used in the plastic industry for injection and blow molding, metal working cutting oils, welding equipment, die-casting and machine tooling, chemical processing, pharmaceutical formulation, food and beverage processing, paper and cement processing, vacuum systems, X-ray diffraction, power supplies and power generation stations, analytical equipment, semiconductors, compressed air and gas cooling. They are also used to cool high heat specialised items such as MRI machines and lasers, and in hospitals, hotels and campuses.
The chillers for industrial applications can be centralised, where each chiller serves multiple cooling needs, or decentralised where each application or machine has its own chiller. Each approach has its advantages.