How is the temperature of the screw water chiller controlled?
How is the temperature of the screw water chiller controlled? It is the ultimate purpose of the screw water chiller and an important content of the screw water chiller to be met and maintained at the temperature of the process. Maintain a constant temperature of the cooling means that the operation condition of the screw water chiller unit and the refrigerating effect outside conditions to meet the demand of the load change at any time, make the refrigerating capacity of the screw water chillers and always maintain the dynamic balance between load.
Screw water chiller consists of a series of parts, from the control point of view, it includes multiple resistance capacity links, each link has its own time constant, there is a certain reaction lag, there are many interference factors, and the screw water chiller unit operation mode after stability returns over a period of time, no matter adopt what kind of control mode, temperature fluctuation of the cooling always inevitable, can only be raised according to the process of constant temperature control accuracy requirement, take corresponding control measures, will be the temperature of the cooling control in the permitted range.
Screw water chiller is a kind of energy saving, environmental protection, precision, less than the energy saving of plus or minus 0.01 ℃ temperature deviation screw water chiller. What are the conditions of the screw water chiller? Let's see.
(1) condenser: in the process of refrigeration, the condenser ACTS as an output heat and condenses the refrigerant.
(2) compressor: the compressor is the core component of the whole refrigeration system, and also the source of the compression of refrigerant. Its effect is to convert the input energy into mechanical energy, which compresses the refrigerant.
(3) the receiver: the reservoir is installed in the condenser and is connected directly to the drain pipe of the condenser. The refrigerant liquid of the condenser should flow unimpeded into the receiver so as to make full use of the cooling area of the condenser.
(4) the thermal expansion valve, thermal expansion valve in the cooling system is not only the flow regulating valve, throttle valve in cooling equipment, it in the refrigeration equipment installed in the filter drier, between the evaporator and its thermal bag is wound in the evaporator outlet.
(5) evaporator: evaporator is used to absorb the heat transfer equipment of the cooled medium by evaporation of the refrigerant liquid. Its function in the refrigeration system is to absorb heat. In order to ensure that the evaporation process can be carried out in a stable and lasting way, the evaporative gas must be pumped out continuously by the refrigeration compressor to maintain certain evaporation pressure.
(6) electrical control system: screw water chiller electrical control system includes power supply part and automatic control part. The power supply is connected to the compressor, fan, water pump, etc. The automatic control part includes temperature controller, pressure protection, delay device, relay, overload protection and other combinations to meet the automatic start and stop of water temperature, protection and other functions.
(7) refrigerant: most used in modern industrial screw water chillers are using R22 as refrigerant, due to the gradually banned CFC refrigerants, refrigerant R410A and pure hydrocarbon refrigerants of energy conservation and environmental protection will be gradually used. Refrigeration is the liquid work in the refrigerant system, its main function is to carry heat, and to achieve endothermic and exothermic when the state changes.
(8) screw water chiller dry filters: in refrigeration cycle must prevent moisture and dirt to enter, such as the source of the water main is the newly added refrigerant and oil contain trace moisture, or because the maintenance system of air into the water. If the system in the water is clean and has not been ruled out, when the refrigerant through the throttle valve (thermal expansion valve or capillary), due to the pressure and temperature drop sometimes frozen into ice water, make the channel block, affect the normal operation of refrigeration equipment. Therefore, the drying filter must be installed in the refrigeration system.