Introduction of industrial chiller

What is an industrial chiller?

The chiller is a cooling water device that can provide constant temperature, constant current and constant pressure. It is widely used in all walks of life, and is also often referred to as freezers, refrigerators, ice water machines, chilled water machines and coolers. Vapor compression chillers consist of four main components: compressor, evaporator, condenser and throttling device.

How industrial chillers work?

The operation of the industrial chiller system is through three interrelated systems: the refrigerant circulation system, the water circulation system, and the electrical automatic control system.

The refrigerant (ie, the refrigerant) absorbs the heat of the object to be cooled in the evaporator and vaporizes it into steam. The compressor continuously extracts the generated steam from the evaporator and compresses it. The compressed high-temperature and high-pressure steam is After being sent to the condenser, it releases heat to the cooling medium (such as water, air, etc.) and condenses into a high-pressure liquid. After being depressurized by the throttling mechanism, it enters the evaporator, vaporizes again, and absorbs the heat of the object to be cooled, and so on. During heating, the refrigerant changes the flow direction of the refrigerant through the four-way valve. The flow direction of the refrigerant is just opposite to that during cooling. The refrigerant first passes through the evaporator, then to the condenser, and then returns to the compressor to complete the heating cycle.

Schematic of a typical chilled-water system.  

The basic composition of the chiller refrigeration system


The compressor is the core component of the entire refrigeration system and the source of power for refrigerant compression. Its function is to convert the input electrical energy into mechanical energy, compress the refrigerant vapor, increase the temperature and pressure and discharge it to the condenser.


In the refrigeration process, the condenser plays the role of outputting heat and condensing the refrigerant. After the high-pressure superheated vapor discharged from the refrigeration compressor enters the condenser, it will transfer all the heat absorbed during the working process, including the heat absorbed from the evaporator and the refrigeration compressor and in the pipeline to the surrounding medium (water or Air) is taken away, and the high-pressure superheated vapor of the refrigerant is re-condensed into a liquid. (According to the different cooling media and cooling methods, condensers can be divided into three categories: water-cooled condensers, air-cooled condensers, and evaporative condensers.)


The liquid accumulator is installed after the condenser and is directly connected to the discharge pipe of the condenser. The refrigerant liquid of the condenser should flow into the liquid receiver smoothly, so that the cooling area of the condenser can be fully utilized. On the other hand, when the heat load of the evaporator changes, the demand of the refrigerant liquid also changes accordingly, and the liquid accumulator plays the role of adjusting and storing the refrigerant at that time. For the small chiller refrigeration system, the liquid receiver is often not installed, but the condenser is used to adjust and store the refrigerant.

Filter drier

In the refrigeration cycle of the chiller, it is necessary to prevent the entry of moisture and dirt (oil, iron filings, copper filings), etc. The source of moisture is mainly the trace moisture contained in the newly added refrigerant and lubricating oil, or due to the air during maintenance of the system. moisture from entering. If the water in the system is not completely removed, when the refrigerant passes through the throttle valve (thermal expansion valve or capillary), the water will sometimes freeze into ice due to the drop in pressure and temperature, which will block the channel and affect the normal operation of the refrigeration device. Therefore, a filter drier must be installed in the chiller refrigeration system.

Thermal expansion valve

The thermal expansion valve is not only a flow control valve in the chiller refrigeration system, but also a throttle valve in the refrigeration equipment. It is installed between the drying filter and the evaporator in the refrigeration equipment. Its temperature sensing package is wrapped in the evaporation. outlet of the device. Its main function is to throttle and depressurize the high-pressure and normal-temperature refrigerant liquid when it flows through the thermal expansion valve, and turn it into a low-temperature and low-pressure refrigerant wet vapor (mostly liquid, a small part of which is vapor) into the evaporator and vaporize in the evaporator. Absorb heat to achieve the purpose of cooling and cooling.


The evaporator is a heat exchange device that relies on the evaporation (actually boiling) of the refrigerant liquid to absorb the heat of the cooled medium. Its function in the refrigeration system is to absorb heat (or output cold). In order to ensure that the evaporation process can be carried out stably, it is necessary to continuously pump the evaporated gas with a refrigeration compressor to maintain a certain evaporation pressure.

The refrigerant

Refrigerant is the flowing working medium in the refrigeration system. Its main function is to carry heat, and to absorb and release heat when the state changes. Most industrial chillers used in modern industry use R22 or R12 as refrigerant. With the increasing emphasis on environmental protection, environmentally friendly refrigerants such as R407C and R134A will gradually replace refrigerants such as R22 that are harmful to the environment.

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