Overview of a centrifugal water-cooled chiller unit

A、Centrifugal water-cooled chiller unitcharacteristic

1. Use R134a refrigerant, which is an internationally recognized environmentally friendly refrigerant and an HFC working fluid.

2. R134a is a positive pressure refrigerant that does not require an exhaust system, and the ventilation design of the computer room is simple.

3. Use Hanzhong two-stage centrifugal compressor.

4. Use an efficient falling film (spray) evaporator.

5. The unit is equipped with an oil cooler, which is cooled by refrigerant and does not require maintenance.

6. Use an independent oil return system (injection pump oil return) to ensure timely oil return under any load conditions.

7. The oil pump is built into the oil tank of the compressor unit, so there is no risk of leakage.

8. Adopting a fixed orifice plate throttling device without moving parts, the refrigerant flow can be adjusted in a timely manner under variable loads and working conditions without hysteresis, ensuring stable operation of the unit.

9. The dedicated microcomputer control system uses Chinese/English screens to clearly display various operational data, making operation extremely convenient.

B、 high reliability

1. Professional Design

With years of experience in the research, production, and sales of centrifugal water-cooled chillers, Hanzhong, a centrifugal compressor manufacturer, introduced scientific research achievements from the Industrial Technology Research Institute and NREC, a professional centrifuge consulting company in the United States. In 2007, Hanzhong officially launched the C-series centrifugal compressor at Taipei and 2008 Shanghai Refrigeration Exhibition.

2. Authoritative certification

Hanzhong Company has the most advanced large-scale online testing platform for centrifugal units in the industry, which has been audited and evaluated as qualified by the National Compressor Refrigeration Equipment Quality Supervision and Inspection Center (Hefei General Machinery Research Institute). This testing platform strictly follows the requirements of national standards such as GB/T10870-2014, GB/T18430.1-2007, and GB/T 19409-2013. Each water-cooled centrifugal chiller unit undergoes strict full performance testing before leaving the factory to ensure the performance of the unit.

3. Reliable oil return device - injection pump

The Comer centrifugal water-cooled chiller uses an injection pump as the return oil component, powered by medium pressure flash gas, to complete the low-pressure side return oil function without energy loss to the unit.

4. Refrigerant flow control component - orifice plate

(1) Comer uses orifice plates as refrigerant flow control devices. Each set of orifice plates is customized according to the performance of the centrifuge and the unit, achieving the best matching degree with the unit performance.

(2) Two to three orifice plates are used as a set of throttling devices, with the first orifice plate serving as a liquid seal and the second to third orifice plates reducing pressure and throttling. The dynamic balance of the refrigerant itself is utilized to ensure that the unit can adjust the refrigerant flow required by the evaporator in real-time under full load, partial load, and different operating conditions.

(3) Due to the absence of any moving parts in the orifice plate, its reliability is naturally superior to that of various throttle valve units with mechanical transmission when operating at full load. When the liquid column height is H, the static pressure generated by the liquid column sends the refrigerant required for full load from the first orifice plate to the second orifice plate.

When the unit is running at half load, the liquid column height changes from H to H/4. Due to insufficient static pressure, the refrigerant passing through the first orifice plate is half of the full load. The decrease in upstream flow causes flash evaporation between the two orifice plates, and a large amount of flash gas mixed with liquid refrigerant passes through the second orifice plate, reducing the refrigerant flow rate by half.

C、 Efficient and energy-saving

1. Centrifugal compressor

The centrifugal compressor is a two-stage compression system that uses high-strength alloy main shafts, high-strength aluminum alloy enclosed impellers, and high-precision precision gears. The bearings are made of high-strength ball/roller bearings that are not flat bearings, so they are not afraid of sudden compressor stops. The start-up interval can be shortened to 10 minutes, and the bearing life can reach up to 80000 hours.

2. Efficient condenser

Dividing the condenser into upper and lower parts, with a guide plate installed in the middle to direct the liquid refrigerant to the edge of the shell, can significantly improve the heat transfer efficiency of the lower half copper tube. For large tonnage units, this design is very effective, reducing the condensation temperature by about 0.5 ℃ to 1 ℃.

3. Spray type (falling film type) evaporator

(1) The refrigerant entering the evaporator is sprayed downwards from the top of the heat exchange tube array. Liquid refrigerant forms a thin film on the pipe wall and flows downwards, hence it is also known as a 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) After a large amount of refrigerant evaporates, the lubricating oil is concentrated at the bottom of the evaporator, and the return oil pump can smoothly extract the oil and return it to the compressor oil tank.

4. Economizer, oil cooler, and return oil heat exchanger

(1) The application of the three in one technology of economizer, oil cooler, and return oil heat exchanger improves the effective separation of medium pressure saturated flash gas and medium pressure saturated liquid refrigerant generated during system operation in the economizer. The separated medium pressure saturated flash gas is introduced into the compressor to complete the second stage compression.

(2) The rich oil liquid refrigerant from the evaporator is heated into refrigerant vapor and oil in the economizer, and then returned to the compressor oil tank.

(3) The high-temperature refrigeration oil from the compressor first enters the economizer to cool to the appropriate oil temperature, and then is injected into the parts of the compressor that need lubrication.

D、 Advanced Control

1. Microcomputer controller

companyleaveThe heart type water-cooled chiller unit is equipped with an advanced microcomputer controller, which has a calculation speed of only 0.25ms to execute 1K Words programs, ensuring the safe and stable operation of the unit.

2. Human computer interface

The touch screen comes with storage space and has a high response speed, allowing users to real-time monitor the complete operating status of the water-cooled centrifugal chiller. The intuitive operation screen allows for language selection in both Chinese and English. Simply click on the screen to perform unit operations and settings.

3. PID control function

The microcomputer controller adopts advanced PID control function to 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 time and stabilize the water temperature within ± 0.3 ℃ of the target temperature.

4. Unit protection function

Provide overvoltage, undervoltage, three-phase imbalance, and reverse phase protection for the power supply of centrifugal water-cooled chillers to clients. And the unit has up to 30 protection functions.

5. Multiple anti surge functions

The water-cooled centrifugal chiller 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 water-cooled centrifugal chiller automatically adjusts its state when the unit approaches the surge curve during operation.

(2) Control - adjust the operating status in a timely manner when detecting surge in centrifugal water-cooled chillers, 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.

6. Reserve user connection points

(1) Reserve control points for cooling tower fans, cooling water pumps, and chilled water pumps for users, so that the fans and pumps are controlled by the unit and optimize the user system structure.

(2) The centrifugal water-cooled chiller unit is equipped with an alarm output point reserved for remote alarm display.

(3) Reserved with a central monitoring connection point (Modbus RTU communication protocol), allowing the unit to seamlessly connect to the building monitoring system.