Magnetic levitation variable frequency centrifugal chiller unit

1. High driving efficiency: The suspended chiller unit adopts a high-speed motor direct drive structure and magnetic levitation bearing technology, without the need for couplings, gearboxes, and mechanical bearings. The structure is simple and there is no mechanical friction. The transmission 3 adopts an efficient permanent magnet synchronous motor cooled by refrigerant, with an efficiency of up to 97% and strong anti electromagnetic interference ability, which can meet different fields.


2. High heat transfer efficiency: The lubricating oil that participates in the system circulation together with the refrigerant in the magnetic levitation variable frequency centrifugal chiller will adhere to the surface of the heat exchange tube bundle, reducing the heat transfer efficiency. Research has shown that the higher the oil content of a system, the lower its heat transfer efficiency. The magnetic levitation chiller operates without mechanical friction and does not require lubricating oil. It adopts an efficient falling film (spray type) evaporator and an efficient shell and tube condenser to enhance flow turbulence and heat transfer efficiency, ensuring long-lasting and high heat transfer efficiency of the system.


3. The magnetic levitation variable frequency centrifugal chiller has high aerodynamic efficiency: the high-speed permanent magnet synchronous motor and the developed refrigeration compressor adopt a two-stage compressor+inter stage air replenishment technology. Compared with traditional screw compressors and single-stage centrifugal compressors, the aerodynamic efficiency can be increased by 5% to 10%, and the operating range is wider


4. Low operating costs: high driving efficiency, high aerodynamic efficiency, and high heat exchange efficiency. The advantage of these "three highs" is that the operating efficiency of the unit can be improved by 30% to 50% compared to traditional units. By using a composite orifice plate combined with an oil-free system specific electronic expansion valve throttling device, the refrigerant flow can be adjusted in a timely manner under variable loads and working conditions, ensuring stable operation of the unit. For users, the biggest advantage is that it can greatly reduce operating costs.


5. Low operating noise: The system is designed with no oil, which is efficient and energy-saving. The unit has no mechanical friction, and the noise of the magnetic levitation chiller is less than 75dB (A).


6. Simple operation and low maintenance cost: The unit can be equipped with a cloud based remote monitoring system, which can keep track of the unit's operation information at any time. One click start stop+cloud service+maintenance free, with almost no professional maintenance costs in the later stage.

7. Efficient and energy-saving

1) Magnetic levitation centrifugal compressor

The magnetic levitation centrifugal compressor adopts active magnetic levitation bearings and dedicated bearing control system, permanent magnet synchronous motor, fully enclosed two-stage high-strength aluminum alloy impeller, etc., with high performance and long service life.
2) Refrigerant flow control component

Based on the characteristics of the magnetic levitation variable frequency centrifugal chiller, a matching throttling device - a composite orifice plate+electronic expansion valve - is adopted. Ensure that the unit operates at its optimal performance point under both rated and partial load conditions. Composite orifice plate, tailored according to the performance characteristics of the centrifugal unit, utilizes the dynamic balance of the refrigerant itself to ensure that the unit can adjust the refrigerant flow required by the evaporator under different operating conditions.

The specialized electronic expansion valve for oil-free systems uses ceramic bearings instead of standard bearings, and permanent PTFE grease is used on the spindle and nut to ensure long-term stable operation in oil-free systems.

3) Efficient falling film evaporator

(1) The refrigerant entering the evaporator is sprayed downwards from the top of the heat exchange tube array. The liquid refrigerant forms a thin film on the pipe wall and flows downwards, hence the name falling film evaporator. Due to only covering a layer of liquid refrigerant film on the surface of the heat exchange tube, the heat transfer effect is excellent.

(2) The evaporator only has a small amount of liquid refrigerant at the bottom, so the refrigerant filling amount of the unit is relatively low, which meets environmental protection requirements.

(3) Professional design of refrigerant distributor to improve liquid distribution uniformity, avoid local dry pipes, fully utilize heat transfer performance, and enhance unit energy efficiency.

4) Efficient condenser

The condenser is divided into upper and lower parts, with a guide plate installed in the middle to direct the liquid refrigerant to the edge of the shell, which can greatly improve the heat transfer efficiency of the lower half copper tube. This design is very effective and can reduce the condensation temperature by about 0.5 ℃ to 1 ℃.


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8. Advanced control

1) Microcomputer controller

The unit is equipped with advanced Siemens controllers to provide safety protection and ensure stable operation of the unit.

The unit adopts PID control function, which can automatically adjust the load of the unit based on the integer value of the cold water outlet temperature and the target temperature, so as to achieve the required water temperature in the shortest possible time.

2) Human computer interface

The unit is equipped with a Siemens touch screen, which has a high response speed and allows users to real-time monitor the complete operating status of the unit. Intuitive operation screen, simply click on the screen to perform unit operations and settings.

3) Unit protection function

Provide overvoltage, undervoltage, three-phase imbalance, and reverse phase protection for the power supply of the client to the unit. And the unit has multiple protection functions, providing comprehensive guarantee for the safe operation of the unit

(1) Including compressor overload and overheating protection; System high pressure, low pressure, low evaporator outlet temperature and antifreeze protection, low condenser inlet temperature protection, abnormal water flow protection, etc.

(2) Equipped with password protection function to prevent unauthorized personnel from misoperation and causing unit failure;

(3) Equipped with a power on self-test function to prevent abnormal startup of the unit;

(4) It has a condenser cleaning reminder function.

4) Multiple anti surge functions

The unit has advanced multiple anti surge functions, using a combination of prevention, control, and alarm to meet customer cooling capacity requirements within a safe operating range.

(1) Prevention - By accurately calculating the surge curve, the unit automatically adjusts its state when it approaches the surge curve during operation.

(2) Control - adjust the operating status in a timely manner when detecting the occurrence of surge in the unit, effectively controlling the occurrence of surge.

(3) Alarm - If the unit surges for a period of time, it will alert the customer in the form of an alarm and perform a shutdown action.


5) Reserve user connection points and provide cloud services

(1) Reserve control points for cooling tower fans, cooling water pumps, and chilled water pumps to enable them to be controlled by the unit and optimize the user system structure. Reserve alarm output points for remote alarm display.

(2) Reserve a central monitoring connection point (Modbus RTU communication protocol) to enable seamless connection of the unit to the building monitoring system.

(3) Cloud services enable real-time uploading and monitoring of operational data, ensuring reliable operation of magnetic levitation variable frequency centrifugal chillers.