Chiller units are a type of cooling system used in a variety of industrial and commercial applications. They are used to cool air or liquids, and can be either air-cooled or water-cooled. Chiller units are composed of several components, including a compressor, condenser, evaporator, and expansion valve. The compressor compresses a refrigerant gas, which is then passed through the condenser, where it is cooled and condensed into a liquid. The liquid is then passed through the evaporator, where it absorbs heat from the air or liquid being cooled. Finally, the liquid is passed through the expansion valve, where it is reduced in pressure and temperature, allowing it to evaporate and cool the air or liquid. Chiller units are an efficient and cost-effective way to cool air or liquids, and are used in a variety of industries, including food and beverage, pharmaceutical, and HVAC.