Description

A chiller is a machine that removes heat from a liquid coolant, typically water or a water-glycol mixture. This chilled liquid is then circulated through a heat exchanger to cool equipment, or another process stream (such as air or process water). Chillers are used in a wide variety of applications, including: Air conditioning in buildings Industrial process cooling Data center cooling Ice rinks Food and beverage processing There are two main types of chillers: vapor-compression chillers and absorption chillers. Vapor-compression chillers use a refrigerant to absorb heat from the chilled water loop. The refrigerant is then compressed, which raises its temperature. The hot refrigerant is then circulated through a condenser, where it rejects heat to the ambient air or cooling water. The cooled refrigerant is then expanded through an expansion valve, which lowers its pressure and temperature. The low-pressure, low-temperature refrigerant then returns to the evaporator, where it can absorb more heat from the chilled water loop. Absorption chillers use a heat source, such as hot water or steam, to drive the cooling process. The heat source is used to generate a refrigerant solution, which is then absorbed by a lithium bromide absorbent. The absorption process releases heat, which is rejected to the ambient air or cooling water. The lean refrigerant solution is then regenerated by boiling off the refrigerant, which can then be used to absorb more heat from the chilled water loop.