The difference between chilled water, cooling water and condensed water and the principle of refrigeration

The difference between chilled water, cooling water and condensed water and the principle of refrigeration

The central air-conditioning host is composed of a compressor, an evaporator, a condenser, and a throttle valve. The compressor provides energy. The condenser reduces the temperature of the refrigerant from the compressor. The medium is water. This water is cooling water. , It is connected to the cooling tower. The evaporator absorbs heat when the refrigerant evaporates. The water flowing through the evaporator is chilled water. After the chilled water absorbs the heat, the temperature decreases. After passing through the air conditioning unit, the cold air is blown into the room for cooling. Compared with household air conditioners, the indoor unit is the evaporator, and the outdoor unit is the condenser, but the household is cooled by the wind, and the central air conditioner is the water flowing through the evaporator and then the indoor heat exchange.

　　 1. The difference between chilled water/cooling water/condensed water

　　 Cooling water lowers the temperature of the refrigerant, the water flowing through the condenser is cooling water, and the water flowing through the evaporator is chilled water.

The condenser reduces the temperature of the refrigerant coming out of the compressor. The medium is water. Water cannot be used as a refrigerant. The main refrigerants include ammonia, carbon dioxide, sulfur dioxide, chloroform, freon, etc., and water is used as the cooling carrier. Agent.

　　 Chilled water is to send the cooling capacity of the air conditioner into the room through pipes and pumps, and then exchange it to the space by the room’s fan coil. Simply put, chilled water is a means of transportation that transfers the cooling capacity from the air-conditioning room to the room where it is used.

　　Cooling water is the air conditioner that generates a lot of heat during the cooling process through the pipe. The water is pumped into the outdoor cooling tower for cooling, that is, the cooling water is a transportation tool that sends the heat generated by the host out of the outdoor.

　　 Condensate is the cold condensed water generated from the air by the room fan coil during the heat and cold exchange, and has nothing to do with the water in the system.

Chilled water/cooling water/condensed water can be understood together. The host and terminal in the water system exchange heat through chilled water, the host and cooling tower exchange heat through cooling water, and the terminal air treatment equipment receives the cold and heat of the chilled water. Heat exchange with indoor air will produce condensation.

　　 Chilled water-water to cool the evaporator, cooling water-water to cool the condenser, condensed water-water condensed when the temperature drops.

　　 Water source water system consists of water source water intake device, water intake pump, water treatment equipment, water pipe network and valve accessories. The refrigeration working condition can be realized by valve switching, even if the water source water enters the condenser, the refrigerating cycle water of the evaporator is connected to the user system. (On the contrary, it is heating condition)

　　Cooling water is generally achieved by cooling water towers, which generally reduce water at room temperature 35-40 degrees to 15-20 degrees. If a lower temperature is required, the cooling water tower cannot be realized, and it needs a refrigeration unit (ice water machine, some also called water chiller), and the inlet water temperature of the ice water machine can be normal temperature, and the outlet water temperature can reach -50 ~ -5 degrees, some cascade refrigerators can achieve temperatures below -150 degrees. This water is frozen water.

　　 For example, in the injection molding industry, the molding machine is required to cool down. If the working environment temperature of some molds is not high, cooling water is enough, but some molds need the temperature of the frozen water when molding. Usually in order to improve the cooling efficiency and energy saving purposes, the cooling water tower is used for the first principle of cooling, and then connected to the refrigeration unit to output the chilled water. Article source Refrigeration Encyclopedia.

　　 The distinction between hot and cold water is relatively speaking, mainly the setting of a limit value for the temperature in the demand environment (working condition).

　　 2. Refrigeration/heating principle

　　 The compressor compresses the gaseous refrigerant into high temperature and high pressure gaseous refrigerant, and then sends it to the condenser (outdoor unit) to dissipate heat and becomes a normal temperature and high pressure liquid refrigerant, so the outdoor unit blows out hot air. Then it goes to the throttle device and enters the evaporator (indoor unit). After the refrigerant reaches the evaporator from the throttle device, the space suddenly increases and the pressure decreases. The liquid refrigerant will vaporize and become a gaseous low-temperature refrigerant, thereby absorbing a large amount of The heat of the evaporator will become cold. The fan of the indoor unit blows the indoor air through the evaporator, so the indoor unit blows out cold wind; the water vapor in the air will condense when it meets the cold evaporator. Water droplets flow out along the water pipe, which is why the air conditioner will emit water. The gaseous refrigerant returns to the compressor to continue compression and continue to circulate.

　　 When heating, there is a component called a four-way valve, which makes the refrigerant flow in the condenser and evaporator opposite to that of cooling. Therefore, when heating, the outdoor air blows cold air, and the indoor unit blows hot air. In fact, it is the principle of discharging heat during liquefaction (changing from gas to liquid) and absorbing heat during vaporization (changing from liquid to gas).

　　Heat pump heating uses the compression condenser of the refrigeration system to heat the indoor air. When the air conditioner is in refrigeration, the low-pressure refrigerant liquid evaporates and absorbs heat in the evaporator, while the high-temperature and high-pressure refrigerant releases heat and condenses in the condenser. The heat pump heating is through electromagnetic reversal, which exchanges the positions of the suction and exhaust pipes of the refrigeration system. The indoor coil of the original cooling work evaporator turns into a heating condenser, so that the refrigeration system absorbs heat from the outside and releases heat to the room to achieve the purpose of heating.　

　　 Under normal circumstances, the air conditioner is actually controlled according to the thermal expansion and contraction of the medium. The indoor part is contracted by cold, and the outdoor part is expanded by heat. The compressor compresses the medium to perform work, which will generate a lot of heat, that is, thermal expansion, and then pass through the throttling device to a much larger space, so that the pressure of the medium is much lower at once. This is Cold shrinkage absorbs heat, and the heat in the room is instantly exchanged into cold gas.