I. Overview
      Shandong Century Changlong New Energy Co., Ltd. production of water-cooled centrifugal chillers because of its single capacity, mainly used in large cooling capacity of the occasion, our company is currently the largest single cooling capacity of 2000RT (7034KW).
      Widely used in hotels, shopping malls, office buildings, exhibition halls, airports, gymnasium and other public facilities comfortable central air conditioning system, and to meet the electronics, pharmaceutical, biological, textile, chemical, metallurgical, pharmaceutical, power, machinery and other industries The different requirements of the process air conditioning system.
Second, the working principle
The two-stage steam compression refrigeration cycle consists of evaporation, compression, chilling and throttling. The working system consists of evaporators, two-stage centrifugal compressors, condensers and throttle units (devices). Components of the closed working system. Economies for the middle qi.

When the unit is cooled, the centrifugal compressor will evaporate the low temperature and low pressure refrigerant in the evaporator from the suction pipe into the suction chamber and enter into the rotating impeller. After the compressor work, the refrigerant vapor becomes high temperature and high pressure gas and enters the exhaust pipe Inside the condenser. The high temperature and high pressure refrigerant gas exchanges heat with the cooling water in the condenser, transfers heat to the cooling water, and the refrigerant gas condenses into the high pressure liquid. The high pressure liquid from the condenser is throttled by the thermostatic expansion valve and enters the evaporator. In the evaporator, the low-pressure liquid refrigerant absorbs the heat of the chilled water and vaporizes the chilled water to cool down and becomes the required low-temperature water. The vaporized refrigerant gas is re-pressurized by the compressor and discharged into the condenser, so that it is circulated again and again, thereby cooling the chilled water.
From the unit out of chilled water, into the indoor fan coil, fresh air units and air conditioning units and other end devices in the indoor and convective air heat exchange, in the process, the water due to the absorption of indoor air heat (to the indoor air heat) And the temperature rises, and the indoor air through the indoor heat exchanger after the temperature drop, driven by the fan, into the room, thereby reducing the indoor air temperature, and the temperature rise after the chilled water in the role of the pump to re-enter the chiller, So the cycle, so as to achieve the purpose of continuous cooling.
Third, the characteristics of water-cooled centrifugal chillers
1, single cooling capacity, energy efficiency is high, COP value of 6.46.
2, the same cooling capacity, especially in large capacity, compared with the full liquid screw chillers, eliminating the need for a large oil device, unit weight and size smaller, small footprint, high energy efficiency.
3, the unit power supply voltage optional, 380V / 6000V / 10000V.
 When using high voltage, greatly reduce the initial investment in equipment, can be directly to the grid voltage supply high voltage motor, eliminating the cost of step-down transformer; greatly reduce the project room investment
4, the unit uses R134a refrigerant. R134a is the HFC working fluid, for the internationally recognized green refrigerant, the ozone layer is not damaged, there is no life limit.
5, standard cold capacity range of cooling capacity: 1231KW ~ 7034KW (model LC350A ~ LC2000A).
Fourth, water-cooled centrifugal chillers introduced
(A) the introduction of the main components
1, energy efficient centrifugal compressor
IMG_257
1.1 Compressor is semi-enclosed, so that its small size, low noise, good air tightness.
    The motor is cooled with liquid refrigerant, the efficiency is high and the motor operating temperature is low and stable, and the stability of the unit is better ensured, and the life of the motor is prolonged. At the same time, the oil leakage, leakage and shaft of the open motor are solved. Series of questions.
1.2 Impeller is fully enclosed, with curved blades and separated leaves to ensure that the unit at full capacity and part of the load efficiency. The impeller design takes into account the thrust balance and conducts the dynamic balance and overspeed test to ensure the compressor is efficient, stable and low noise.
1.3 The position of the guide vane is adjusted by the stepper motor plus the connecting rod structure. Thereby adjusting the position of the guide vanes can cause the compressor to continuously change from the minimum load to the maximum load.
1.4 The compressor is a two-stage compressor, in the entire cycle configuration, set up a energy-saving device, which can play a two-stage compressor performance. In general, the economic efficiency of energy-saving appliances, can enhance the performance of more than 8%.
1.5 use are radial ball bearings. The bearing of the oil circulation demand is quite low, greatly reducing the leakage of oil to the system probability.
1.6 compressors need to lubricate the parts, such as gears, bearings, etc., are basically packaged in the gear box. This ensures the relative independence of the lubrication system. The design maximizes the oil from entering the refrigerant system and improves the cooling efficiency of the centrifugal unit, eliminating the need for additional oil in the unit. In addition, this centralized recovery, centralized supply of the way, can also meet the compressor lubrication system required oil.
2, high efficiency heat transfer tube shell and tube condenser
IMG_258
2.1 efficient heat transfer tube, the use of external fins internal heat exchanger copper tube, greatly enhanced refrigerant side heat transfer capacity, improve the heat transfer coefficient, to ensure that the unit a good cooling effect.
2.2 The internal structure of the optimal design, greatly improving the condenser corrosion resistance, anti-fouling ability, give full play to the condenser heat transfer effect, thus ensuring the unit to achieve a higher level of performance.
2.3 shell with pressure vessel for high-quality steel, production and testing are in line with JB / T4750-2003 "refrigeration device with the pressure vessel" requirement. The cover at both ends of the housing is detachable for easy cleaning and overhaul.
2.4 to avoid the high-speed superheated steam discharged from the compressor outlet directly brushing the condenser, in the condenser along the axial buffer plate with a reasonable distribution of air flow, the heat transfer efficiency greatly improved;
2.5 condenser at the bottom with a subcooler, effectively improve the liquid subcooling, improve the efficiency of refrigeration cycle, improve unit energy efficiency;
2.6 shell and tube condenser is also installed on the safety valve, release valve, etc., to ensure that the shell and tube condenser safety and maintenance of convenience.
3, high efficiency full liquid evaporator
IMG_259
3.1 The use of full-liquid evaporator, relative to the same compressor, can provide a lower heat transfer temperature difference, usually below 1.5 ℃; resulting in higher cooling capacity and higher COP.
3.2 using the most advanced DAE efficient evaporative heat transfer tube, the tube surface of the long spiral ribs and spiral protrusion, the heat transfer coefficient and heat transfer capacity greatly improved.
3.3 The use of a unique heat exchanger refrigeration process design technology, a reasonable system matching to ensure that the cooling process and the water side of the balance of the balance, give full play to the high efficiency of the heat exchanger; and reasonable system matching, the unit more energy efficient.
3.4 in the evaporator in the shell along the direction of the configuration of the refrigerant liquid distributor, so that the case of any load in the case of the shell can be evenly distributed, so that the best heat transfer effect;
3.5 After evaporation, in order to avoid the refrigerant droplets into the compressor impeller, in the evaporator tube bundle above the defogging performance of a good vapor-liquid separator to prevent the press liquid to prevent dirt into the press.
3.6 Shell with pressure vessel for high-quality steel plate, the shell at both ends of the cover is removable, easy to clean and overhaul.
4, throttling device
4.1 According to different working conditions and different requirements, select the orifice, orifice and solenoid valve in parallel, the orifice and electric control valve in parallel with three kinds of throttle program;
4.2 The unit adopts the adjustable orifice plate to make the throttling, the pressure loss in the process of throttling is small, the adjustment speed is quick and the precision is high, and the efficiency of the unit is effectively improved. Because the orifice plate has no moving parts, its reliability is superior to the mechanical transmission Various types of throttle valves.
4.3 Each group of holes are tailored according to the centrifuge and unit performance, and the performance of the unit to achieve the best degree of matching.
4.4 Microcomputer senses the evaporator level and automatically adjusts the orifice opening.
4.5 When the load in the range of 10-100% change, can be efficient operation.
4.6 Compared with other forms of throttle devices, advanced control, with the compressor with a tacit understanding, energy saving effect.
5, color image display microcomputer PLC controller
IMG_260
5.1 color display, touch screen is more simple.
    Touch screen display control center is an advanced microprocessor control system, to provide users with a convenient, efficient, visual interface, but also with real-time monitoring, data logging, security and other functions. The control center with 8 "color display, the user simply touch the screen button to perform the corresponding function operation, the screen clear.
5.2 control more accurate, more stable output.
    The unit control system can not only adjust the load according to the cold water stability, but also according to the cold water inlet temperature change rate to predict the air conditioning load changes. Can make the unit to adjust the load faster, more stable water temperature, to avoid frequent changes in load, thereby improving the life of the press.
5.3 privilege rating, password protection security
    The control center has improved the security access password for the operator, preventing the parameter settings from being changed without permission. Access levels are in two levels, user level and vendor level. Boot and enter the user parameter settings interface need to enter the user password, enter the factory parameter setting screen requires factory password, this password has the company's engineering commissioning personnel to ensure the safe operation of the unit.
5.4 Unit protection function
   The unit has various protection measures such as power protection, press overheating and overload protection, high pressure and low voltage protection of system, temperature protection of press oil tank.
5.5 multiple anti-surge function
  The unit has advanced multi-surge function, the use of prevention, control, alarm combination of the way, so that the unit safe operation in the safe range to meet customer demand for cooling capacity.
◆ Prevention: Through the accurate calculation of the surge curve, when the unit operating conditions close to the surge curve, the unit will automatically adjust the load.
◆ control: When the unit detects a surge in the timely control, can effectively control the occurrence of surge.
◆ alarm: the unit appears in the surge phenomenon, the display interface to display alarm information to remind customers and stop the unit to run.
5.6 chain function
◆ unit set aside cooling tower fan, cooling water pump, air conditioning pump control point, can be easily carried out chain control.
◆ unit set aside remote start, alarm and run signal output point, to facilitate remote operation
◆ The controller reserves the RS485 interface and the standard MOdbus-RTU communication protocol. The customer can easily incorporate the unit control into the building automation control system.
6, the introduction of other parts
6.1 flash tank
IMG_261
Carbon steel cylinder, the internal design is to prevent the refrigerant liquid into the compressor. For the press to provide the middle qi, improve the efficiency of the unit.
Install the liquid level switch, when the economic liquid level is higher than the design level, the unit alarm shutdown.
6.2 oil cooler
IMG_262
The use of efficient plate heat exchanger, through the oil temperature control, the use of the condenser refrigerant circulation to achieve the purpose of cooling the compressor lubricants.
Generally set higher than 50 ℃, the opening of the oil cooler solenoid valve; oil temperature below 40 ℃, close the oil cooler solenoid valve.
After installation in the oil cooler, the main function is to filter the impurities or foreign matter in the oil path to avoid clogging in the system cycle.
1. Removable. When the pressure drop is large before and after the filter, it can be cleaned and cleaned.
6.3 oil precision filter
2. Install the oil pressure difference control, the pressure set 1.5bar.
IMG_263
6.4 buffer tank
Installed in the pump outlet, in order to buffer the pulse of the pump outlet.
6.5 oil flow switch
Installed in the oil lubrication circuit, in order to ensure adequate oil lubrication, to avoid the press because of poor lubrication and failure. The current action point is the default value, 3.0 ~ 3.8L / min. The maximum flow rate is 67L / min.
6.6 ejector pump
The use of high-pressure condenser gas injection of low-pressure fluid to achieve the purpose of the system back to the oil. Part of the ejector evaporator "oil-rich" refrigerant in the oil, the other part of the suction compressor suction side of the bottom of the accumulation of oil
6.7 hot air bypass electric control valve
When the guide vane is opened or closed to within 10%, the valve opens. This valve opens when the unit is running on the surge protection line. The valve is installed between the condenser and the evaporator.
6.8 oil heater
    Each compressor has two 500W oil heater, when the oil from the evaporator back too much or the external ambient temperature is low, the oil temperature may be low, the oil mixed in the liquid refrigerant, will lead to lubrication Reduce the damage to the compressor. At this time to open the oil heater, to ensure that no liquid refrigerant refrigerant. Before starting the compressor, the oil temperature should be heated to above 40 ℃.
6.9 Refrigerant heater
    2 sets of 300W refrigerant heater installed in the compression room, long after the shutdown again before opening, please open the refrigerant heater for at least 24 hours, so that the body temperature is higher than the system requirements to avoid the compressor refrigerant condensation. If the ambient temperature is too low, it is advisable to turn on the refrigerant heater during shutdown.
5, water-cooled centrifugal chillers energy-saving certification
IMG_264
Six, water - cooled centrifugal chillers configuration table
Serial number
Models and Specifications
Remarks
1
Centrifugal compressor
Taiwan Han Zhong
2
Shell and tube condenser
Grader
3
Full liquid evaporator
Grader
4
Microcomputer controller
Germany Siemens
5
Plate heat exchanger
Guangdong Jiefeng
6
Electric valve
Harley
7
The electromagnetic valve
Danish Danfoss
8
Orifice plate
Grader
9
Dry filter
Tianjin Fascist
10
High and low pressure sensor
Danish Danfoss
11
AC contactor / thermal relay
Germany Siemens
I produced the water-cooled centrifugal chillers have the following characteristics:
1, energy efficiency: single cooling capacity, high efficiency, conventional unit COP to achieve national energy efficiency level; ultra-efficient unit COP value of up to 7.05 or more. Included in the national government energy-saving procurement list.
2, environmental protection: the unit using R134a refrigerant. R134a is the HFC working fluid, for the internationally recognized green refrigerant, the ozone layer is not damaged, there is no life limit.
3, the use of high efficiency semi-closed centrifugal compressor, two-stage compression and energy-saving design, the second level of compression to qi to reduce the power consumption of the compressor, the unit can enhance the overall performance of more than 10%.
4, the use of national advanced real-time flow control method, the control of successful access to national invention patents.
5, Siemens intelligent PLC control system and a variety of throttle control program, the control accuracy of up to 0.2 ℃, the unit running more reliable.
6, the use of high efficiency falling film evaporator, the heat transfer efficiency than the traditional evaporator to improve more than 20%, the successful access to national utility model patents.
7, start a variety of ways, voltage optional
  Start mode optional: direct start (high voltage), star angle start, soft start, frequency start.
  Unit power supply voltage optional: 380V / 6000V / 10000V, to reduce the initial investment, can be directly connected to the grid, eliminating the need for step-down transformer.
8, can achieve remote operation monitoring
Intelligent remote monitoring technology, to achieve the "unit alarm message SMS reminder", "unit fault remote processing", "unit running data memory" and other monitoring functions. So that users use more at ease, the unit running more efficient.
9, water-cooled centrifugal chillers received 10 national patent certificate.
Centrifuge products is the main sales group flagship product, through the Group's early publicity and promotion
And market feedback information statistics, centrifuge products in 2016 will usher in a broader sales market prospects.