How do chillers work?
Industrial chillers cool process fluids (water or a water/glycol mixture) which absorb heat from what is being cooled and then pass through the chiller where the heat is removed from the fluid and transferred elsewhere. Chillers therefore do not produce cold, but remove heat.
Refrigeration units consist of four basic components:
- an evaporator
- a compressor
- a condenser
- an expansion unit
Each refrigeration system contains a refrigerant.
The process begins with a low-pressure refrigerant entering the evaporator. Inside the evaporator, the refrigerant is heated, thus undergoing a phase change to a gas. The gaseous refrigerant enters the compressor, which increases the pressure. The high-pressure refrigerant goes to the condenser, which rejects the heat using cooling water from a cooling tower or air from the surroundings, condensing it into a high-pressure liquid.
The condensed refrigerant then goes to the expansion unit, which has a valve that acts as a metering device to limit the flow of refrigerant into the system. As a result, this lowers the refrigerant pressure and begins the cooling process again. The entire process is known as the refrigeration cycle.