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What Are the Main Components of a Chiller and What Do They Do?

What Are the Main Components of a Chiller and What Do They Do?

A chiller is one of the most important electrical appliances, which can easily be spotted in any building or an industrial setup. There are three basic types of chillers, namely air-cooled chillers, water-cooled chillers, and evaporated condensed chillers. However, no one spares a minute to talk about the key components that combine to form a chiller.

Let’s take a look at the main components of a chiller and what they do.


The compressor is the most important component of a chiller. Its job is to ensure the movement of the refrigerant throughout the system. A compressor is placed between the evaporator and the condenser. It has an electric motor as the driving force, which is either mounted outside or placed internally.


A condenser is located close to the expansion valve and compressor.  The job of the condenser is to remove the heat from the refrigerant that is picked up in the evaporator.  Condensers normally come in two types, i.e. air-cooled condensers and water-cooled condensers. 

Expansion Valve

The expansion valve expands the refrigerant and increases its volume, which allows the refrigerant to pick up heat in the evaporator. There are different types of expansion valves, but the most common type is the thermal expansion valve which is pilot operated.


An evaporator is used to pick up heat from the building and send it to the refrigerant so that it can be sent to the cooling tower. An evaporator is located between the compressor and the expansion valve.  The water is cooled when the heat is extracted. This chilled water is sent throughout the building for the provision of air conditioning. Then, the chilled water returns to the evaporator with heat from the building.

Power Unit

The power unit is another crucial component of the chiller that controls the supply of electricity to the chiller. It can either be mounted to the chiller or to the plant room wall along with the power cables. A power unit comprises of a circuit breaker, starter, speed controller, and power monitoring equipment.

Water Boxes

Water boxes are mounted to the evaporators and condensers in a water-cooled chiller. A water box directs the flow and separates the entrance from the exit. A water box has around 1 or 2 entrance and exit holes, depending upon the number of passes in the evaporator and condenser.

Control Unit

A control unit is mounted to the chiller. It monitors the efficiency of the chiller and makes certain adjustments if things are not going the way they should. Control units have alarms for the safety teams, and instant system shutting options in the case of an emergency.

The overall performance of a chiller depends heavily upon sooth functioning of each of the above mentioned components. Without any one of them, the chiller will seize to perform the way it should. For help and information regarding chillers, feel free to visit our website.