The air-cooled screw chiller is a refrigeration equipment that uses a screw compressor as the core and dissipates heat through air cooling. It is widely used in industrial cooling, commercial air conditioning and other fields. Its core components and functions are as follows:
1、 Core components and their functions
1. Screw compressor
Function: The power source of the refrigeration cycle compresses refrigerant gas through the rotation of the screw rotor, increasing its pressure and temperature, and providing energy for the refrigeration cycle.
Features:
Compact structure, smooth operation, low vibration, and low noise.
Suitable for medium to large refrigeration capacity requirements (typically ranging from 50kW to 2000kW).
Some models use frequency conversion technology to adjust the compressor speed according to load changes, achieving energy-saving operation.
2. Air cooled condenser
Function: Cool the high-temperature and high-pressure refrigerant gas discharged by the compressor into liquid form, and release heat to the ambient air.
Structure:
Composed of copper tubes and aluminum fins, the refrigerant flows inside the copper tubes, and air is forced to convection and dissipate heat through the surface of the fins.
Equipped with axial or centrifugal fans to accelerate air flow and improve heat dissipation efficiency.
Advantages: No need for cooling water system, saving water resources, flexible installation, suitable for areas with water shortage or poor water quality.
3. Evaporator
Function: The refrigerant absorbs heat from the cooling medium (such as water or air) in the evaporator, evaporates into a gaseous state, and achieves the cooling effect.
Type:
Shell and tube evaporator: The refrigerant evaporates outside the tube, and the cooled water flows inside the tube, suitable for high flow and large temperature difference scenarios.
Dry evaporator: The refrigerant evaporates inside the tube, and the cooled water flows outside the tube, with high heat transfer efficiency, but the refrigerant charging amount needs to be controlled.
Application: Provide chilled water for air conditioning systems or directly cool process media (such as in the chemical and pharmaceutical industries).
4. Throttle device (expansion valve)
Function: Throttle and reduce the pressure of high-pressure liquid refrigerant to low-pressure wet vapor, regulate the flow of refrigerant entering the evaporator, and maintain stable evaporation pressure.
Type:
Thermal expansion valve: detects the outlet temperature of the evaporator through a temperature sensor and automatically adjusts the opening.
Electronic expansion valve: driven by a motor, with higher precision and faster response speed, suitable for variable frequency units.
5. Electrical control system
Function: Monitor the operating status of the unit, control the start and stop of the compressor, fan speed, expansion valve opening, etc., to achieve automated operation and protection functions.
Function:
Temperature control: Automatically adjust the cooling capacity according to the set temperature.
Pressure protection: Monitor high and low pressure to prevent system overvoltage or undervoltage.
Fault diagnosis: Display fault codes for easy maintenance.
Remote monitoring: Supports RS485/Modbus communication and can be connected to building automation systems.
6. Auxiliary components
Oil separator: Separate lubricating oil from the compressor exhaust to prevent oil from entering the condenser and evaporator and affecting heat transfer efficiency.
Dry filter: absorbs moisture and impurities in the refrigerant to prevent ice blockage and dirt blockage.
Liquid reservoir: stores excess refrigerant and balances the refrigerant demand when the system load changes.
Liquid sight glass: Observe the flow state of refrigerant and determine whether the system is lacking in fluorine or moisture.
Safety valve: Automatically releases pressure when the system pressure exceeds the set value, protecting equipment safety.
2、 Working principle
Compression process: The compressor sucks in low-temperature and low-pressure refrigerant gas and compresses it into high-temperature and high-pressure gas.
Condensation process: High temperature and high pressure gas enters the air-cooled condenser, and is forced to dissipate heat through convection by the fan, condensing into high-pressure liquid refrigerant.
Throttling process: The liquid refrigerant is throttled and depressurized through an expansion valve, becoming low-pressure wet vapor.
Evaporation process: Wet vapor enters the evaporator, absorbs heat from the cooled medium, evaporates into low-temperature and low-pressure gas, and returns to the compressor to complete the cycle.
3、 Application scenarios
Commercial air conditioning: Central air conditioning systems for large shopping malls, hotels, office buildings, etc.
Industrial cooling: Process cooling requirements for industries such as chemical, pharmaceutical, and electronics.
Data center: Provide a constant temperature and humidity environment for server rooms.
Special fields: such as medical freezing, food processing, and other scenarios that require precise temperature control.
4、 Summary of Advantages
Energy saving and efficient: Screw compressors have high efficiency, and some models use frequency conversion technology to further save energy.
Easy installation: The air-cooled design eliminates the need for cooling towers and water pumps, saving space and initial investment.
Stable operation: high degree of automation control, low failure rate, and simple maintenance.