What is a water chiller?

I. What is a chiller?
A chiller is a cooling device that can provide constant temperature, constant flow, and constant pressure. The chiller operates on physical principles. First, a certain amount of water or other liquid is injected into the water tank inside the machine. The water or other liquid is cooled by the chiller's refrigeration system. Then, a water pump sends the low-temperature cooling water or other liquid to the equipment that needs cooling. The chilled water of the chiller takes away the heat and then the temperature rises and flows back to the water tank to achieve the cooling effect. The cooling water temperature can be automatically adjusted as required. Long-term use can save water. Therefore, the chiller is a standard energy-saving device. It can also be summarized in one sentence as cooling normal temperature water to a certain temperature through the compressor of the chiller to enhance the cooling of molds or machines. Generally, the output chilled water temperature is 5 degrees Celsius. Customers can specially request an output temperature of 3 degrees Celsius.

II. What is the structure of a chiller?
Chiller frame:
The cooling capacity of small industrial chillers is generally 4KW to 25KW. Therefore, models with a cooling capacity of less than 30KW are relatively light in weight. They are all made of aluminum frames with iron-plastic sprayed door panels installed inside. All heavy objects, such as water tanks, compressors, water pumps, and the weight of the frame, are supported and fixed by the bottom bracket welded with angle iron. Rubber feet are connected below the bottom bracket to complete the vibration reduction of the whole machine.

The gaps formed by the rubber feet and the ground and the gaps in the door panels can form natural convection to complete the natural cooling of the compressor and water pump. For large industrial chillers with a cooling capacity of more than 30KW, the whole machine is heavier and is made of an iron frame, but its structure is generally the same as above.

III. How does the refrigerant circulation system of a chiller operate?
The liquid refrigerant in the evaporator absorbs heat from the water and begins to evaporate. Eventually, a certain temperature difference is formed between the refrigerant and the water. After the liquid refrigerant is completely evaporated and turns into a gaseous state, it is sucked in and compressed by the compressor (pressure and temperature increase). The gaseous refrigerant absorbs heat through the condenser (air-cooled/water-cooled), condenses into a liquid, and enters the evaporator through the thermal expansion valve (or capillary tube) for throttling to complete the refrigerant circulation process.

IV. What are the basic components of a chiller refrigeration system?
Compressor: The compressor is the core component of the entire refrigeration system and also the source of power for refrigerant compression. Its function is to convert the input electrical energy into mechanical energy and compress the refrigerant.
Condenser: In the refrigeration process, the condenser plays a role in outputting heat energy and condensing the refrigerant. After the high-pressure superheated vapor discharged from the refrigeration compressor enters the condenser, it transfers all the heat absorbed during its working process, including the heat absorbed from the evaporator, the refrigeration compressor, and the pipeline to the surrounding medium (water or air) and takes it away; the refrigerant high-pressure superheated vapor re-condenses into a liquid. (According to different cooling media and cooling methods, condensers can be divided into three categories: water-cooled condensers, air-cooled condensers, and evaporative condensers.)
Receiver: The receiver is installed after the condenser and is directly connected to the drain pipe of the condenser. The refrigerant liquid of the condenser should flow into the receiver unimpeded. In this way, the cooling area of the condenser can be fully utilized. On the other hand, when the heat load of the evaporator changes, the demand for refrigerant liquid also changes. At that time, the receiver plays a role in regulating and storing the refrigerant. For small chiller refrigeration systems, a receiver is often not installed, but the condenser is used to regulate and store the refrigerant.
Drying filter: In the chiller refrigeration cycle, it is necessary to prevent the entry of moisture and contaminants (oil stains, iron filings, copper filings). The main source of moisture is the trace moisture contained in the newly added refrigerant and lubricating oil, or the moisture brought in when air enters during system maintenance. If the moisture in the system is not completely removed, when the refrigerant passes through the throttle valve (thermal expansion valve or capillary tube), sometimes the moisture will freeze into ice due to the drop in pressure and temperature, blocking the channel and affecting the normal operation of the refrigeration device. Therefore, a drying filter must be installed in the chiller refrigeration system.
Thermal expansion valve: The thermal expansion valve is not only a flow regulating valve in the chiller refrigeration system but also a throttle valve in refrigeration equipment. It is installed between the drying filter and the evaporator in refrigeration equipment. Its temperature sensing bulb is wrapped at the outlet of the evaporator. Its main function is to throttle and reduce the pressure of the high-pressure normal temperature refrigerant liquid when it flows through the thermal expansion valve, turning it into low-temperature and low-pressure refrigerant wet vapor (mostly liquid and a small part is vapor) and entering the evaporator. In the evaporator, it vaporizes and absorbs heat to achieve the purpose of refrigeration and cooling.
Evaporator: The evaporator is a heat exchange device that absorbs the heat of the cooled medium by the evaporation (actually boiling) of the refrigerant liquid. Its function in the refrigeration system is to absorb heat (or output cooling capacity). In order to ensure that the evaporation process can be carried out stably and continuously, the evaporated gas must be continuously pumped away by the refrigeration compressor to maintain a certain evaporation pressure.
Refrigerant: Most industrial chillers used in modern industry use R22 or R12 as refrigerants. The refrigerant is the flowing working medium in the refrigeration system. Its main function is to carry heat and achieve heat absorption and release when the state changes.
Electrical automatic control system: There are two types: traditional electromechanical control and computer program control. The former is convenient for maintenance and inexpensive; the latter has an intuitive display of water tank temperature but is more expensive and requires higher skills for maintenance personnel. No detailed description is given here.

V. Where are chillers used?
Generally speaking, it is suitable for factories with various plastic molding equipment. It is also suitable for mechanical equipment that needs to cool the machine temperature, such as machine tools and other equipment. It is also suitable for places that need to cool water temperature, such as cold dryers, dyeing industries, electroplating industries, food industries, sauna baths, and jewelry processing industries.
Industrial chillers are widely used in various industrial productions: