Chiller (water chilling unit)
Also known as: water chiller, water chilling unit
Short definitionA unit that cools water or a glycol mixture circulating in a loop, not the air of a room. The chilled water is piped to a process line, a tank or an air handling unit.
In a chiller, water flows through the evaporator instead of air. The machine cools the water and a pump carries it to wherever it is needed. In air conditioning the water leaves at 7 °C and returns at 12 °C; food processing uses 1/6 °C. Adding glycol allows −10 °C and below. Units with a fan-cooled condenser are air-cooled, those working with a tower are water-cooled.
On a cold room job a chiller is usually wanted for the process next to the rooms: milk cooling, dough water, a beverage line, process water in the preparation hall. A quotation needs the water inlet and outlet temperatures, the flow rate (m³/h) and the outdoor temperature on the hottest day. Capacity falls as the glycol share rises. Without the pump set, buffer tank and freeze protection the system is incomplete.