New Explanation of Basic Knowledge of Small Chiller System

Small water chiller is a kind of water cooling equipment, small water chiller is a kind of cooling water equipment that can provide constant temperature, constant current and constant pressure. The working principle of the small chiller is to inject a certain amount of water into the water tank in the machine, and then cool the water through the refrigeration system of the small chiller, and then the low-temperature cooling water is sent to the equipment to be cooled by the water pump, and the chilled water of the small chiller takes the heat away After the temperature rises, it returns to the water tank to achieve cooling. The cooling water temperature can be automatically adjusted according to requirements, and long-term use can save water. Therefore, a small chiller is a standard energy-saving equipment.

   (1) The cooling principle of a small chiller:

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

   (2) Small chiller refrigerant circulation system:

The liquid refrigerant in the evaporator absorbs the heat in the water and starts to evaporate. At the end of the z*, a certain temperature difference is formed between the refrigerant and the water. The liquid refrigerant is also completely evaporated into a gaseous state and then sucked by the compressor and compressed (pressure and temperature Increase), the gaseous refrigerant absorbs heat through the condenser (air-cooled/water-cooled), condenses into a liquid, and is throttled by a thermal expansion valve (or capillary) to become a low-temperature and low-pressure refrigerant to enter the evaporator, completing the refrigerant cycle process.

  The basic composition of a small chiller refrigeration system:

  1. 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 the working process, including the heat absorbed from the evaporator and refrigeration compressor and in the pipeline, to the surrounding medium (water or Air) taken away; the high-pressure superheated vapor of the refrigerant recondenses into 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.)

  2. Compressor: 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 and compress the refrigerant.

3. Thermal expansion valve: The thermal expansion valve is not only a flow regulating valve in the refrigeration system of a small chiller, but also a throttle valve in the refrigeration equipment. It is installed between the filter dryer and the evaporator in the refrigeration equipment. The temperature sensor is wrapped around the outlet of the evaporator. Its main function is to make the high-pressure and normal-temperature refrigerant liquid throttling and depressurize when it flows through the thermal expansion valve, turning into low-temperature and low-pressure refrigerant wet vapor (mostly liquid, a small part of vapor) into the evaporator and vaporized in the evaporator It absorbs heat to achieve the purpose of cooling and cooling.

  4. Evaporator: 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 capacity). In order to ensure that the evaporation process can be carried out stably and lastingly, a refrigeration compressor must be used to continuously pump the evaporated gas away to maintain a certain evaporation pressure.

   5. Liquid reservoir: The liquid reservoir is installed after the condenser, and it is directly connected with the condenser's drain pipe. The refrigerant liquid of the condenser should flow into the receiver unimpededly, 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 required amount of refrigerant liquid also changes. At that time, the liquid accumulator plays a role of regulating and storing refrigerant. For small and small chiller refrigeration device systems, liquid receivers are often not installed, but condensers are used to adjust and store refrigerant.

6. Filter drier: In the refrigeration cycle of small chillers, 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 moisture caused by air entering during system maintenance. If the moisture in the system is not removed, when the refrigerant passes through the throttle valve (thermal expansion valve or capillary tube), the moisture will sometimes freeze into ice due to the drop in pressure and temperature, blocking the passage and affecting the normal operation of the refrigeration device. Therefore, a filter drier must be installed in the refrigeration system of a small chiller.

  7. Refrigerant: Most small industrial chillers used in modern industry use R22 or R12 as a refrigerant. Refrigerant is the flowing working fluid in the refrigeration system. Its main function is to carry heat and realize heat absorption and heat release when the state changes.