The basic principle of refrigeration system: After the liquid refrigerant absorbs the heat of the object being cooled in the evaporator, it vaporizes into low-temperature and low-pressure vapor, is inhaled by the compressor, compressed into high-pressure and high-temperature vapor, and then discharged into the condenser, exothermic to the cooling medium (water or air) in the condenser, condenses into high-pressure liquid and then throttles down into low-pressure and low-temperature refrigerant through the throttle valve, enters into the evaporator again to absorb heat and vaporize, so as to achieve the cycle of refrigeration. purpose. In this way, the refrigerant in the system completes a refrigeration cycle through four basic processes: evaporation, compression, condensation, and throttling. The water-cooled chiller is mainly composed of a closed scroll compressor, condenser, evaporator, expansion valve, and electric control system.
The compressor is the core of the whole air conditioning system, and also the source of system power. The entire power of the air conditioning, all provided by the compressor, the compressor is equivalent to a physical move from a low potential to a high potential place to go, in the air conditioning, its purpose is to the low-temperature gas compressed by the compressor into a high-temperature gas, and finally the gas in the heat exchanger and other media for heat exchange. Therefore, the quality of the compressor will directly affect the effectiveness of the entire air conditioning.
Water-cooled chillers generally use a hermetic scroll compressor. The hermetic scroll compressor: a refrigeration capacity of 8 to 150 KW, can be used in a variety of air conditioning, refrigeration equipment. The water-cooled scroll chiller, simple and compact structure, high performance, good sealing, low noise, for the future leading models.
The function of the condenser is to cool the high temperature and high-pressure refrigerant superheated vapor discharged from the compressor into liquid or gas-liquid mixture. The heat emitted from the refrigerant in the condenser is taken away by the cooling medium (water or air).
Water-cooled chillers generally use water-cooled condensers. Water-cooled condensers use water as the cooling medium, and the temperature rise of the water takes away the heat of condensation. The cooling water is generally recycled, but a cooling tower or cooling pool is required in the system. The water-cooled condenser can be divided into shell-and-tube condenser and cannula condenser according to its structure form, and the common one is the horizontal shell-and-tube condenser.
The two ends of the horizontal shell-and-tube condenser tube plate are each closed with an end cap, which is cast with a water separator rib designed to match each other, separating the whole tube bundle into several tube groups. Thus the cooling water enters from the lower part of one end cover, flows sequentially through each tube group, and finally flows out from the upper part of the same end cover in the process of 4 to 10 round trips. This can not only increase the flow rate of the cooling water inside the tube, thus improving the heat transfer coefficient, but also make the high-temperature refrigerant vapor from the shell to the end of the tube.
The upper inlet tube enters the bundle of tubes to exchange heat with the cooling water inside the tube. Condensation down the liquid from the lower liquid tube into the liquid storage tank. The cooling tubes of Freon horizontal condensers are generally low-rib copper tubes. This is due to the low heat release coefficient of Freon. It is noteworthy that some Freon refrigeration units are generally not set storage cylinders, only the bottom of the condenser less set up a few rows of tubes, also used for a storage cylinder.
The function of the evaporator is to use the liquid low-temperature refrigerant to evaporate easily under low pressure, change into vapor and absorb the heat of the medium to be cooled, so as to achieve the purpose of refrigeration.
Water-cooled chillers generally use a tank-type (immersion type) evaporator. The refrigerant evaporates in the tube, and the whole evaporator tube group is immersed in the box full of refrigerant. This evaporator can only be used for an open circulation system, so the refrigerant must be non-volatile substances, commonly used as saltwater and water. If the brine is used, the evaporator tube is easy to be oxidized, and the brine is easy to absorb moisture to reduce the concentration. This evaporator can directly observe the flow of the refrigerant carrier.
4. Thermal expansion valve
It controls the refrigerant flow into the evaporator by feeling the superheat of the gaseous refrigerant at the outlet of the evaporator. According to different balancing methods, thermal expansion valves are divided into external balancing type and internal balancing type.
The above information is provided by a water-cooled chiller supplier.