Chillers have many titles in the industry, including chillers, industrial chillers, screw chillers, scroll chillers, compact chillers, centrifugal chillers, air-cooled water chillers, water-cooled chillers Chillers, etc., so many titles are actually included in the chiller, and the main function of the chiller is to refrigerate, control the temperature of the water to provide the cooling temperature and cooling effect required by different materials, let’s learn about cold water Detailed classification of the machine:

First, the classification of chillers

1. According to the cooling method of the condenser: water-cooled chiller, air-cooled water chiller
2. According to the cold water outlet temperature: normal temperature type (5℃, 10℃, 15℃, 35℃), low temperature type (-60℃~-20℃), ultra-low temperature type (-150℃~-25℃)
3. According to the form of compressor: piston chiller, screw chiller, centrifugal chiller
4. According to fuel type: fuel type (diesel, heavy oil), gas type (kerosene, natural gas)
5. According to the form of energy utilization: single cooling type heat pump type, heat recovery type single cooling type, ice cold storage dual function type
6. According to the sealing method: open type, semi-closed type, fully closed type
7. According to the refrigerant: water-cooled chiller, brine chiller, ethylene glycol chiller
8. According to different energy compensation points: power compensation (compression type), thermal energy compensation (absorption type)
9. According to refrigerant: R22, R123, R134a
10. According to different heat sources (absorption type): hot water type, steam type, direct combustion type

Second, the advantages and disadvantages of various chillers

1. Screw chiller

Advantages: simple structure, less moving parts, less wearing parts, only 1/10 of the piston type, low failure rate, long life; smooth circular motion, no “surge” phenomenon during low-load operation, low noise and small vibration ; The compression ratio can be as high as 20, the EER value is high; the adjustment is convenient, it can be adjusted steplessly within the range of 10%, the efficiency is high at partial load, and the power saving is significant; small size, light weight, can be used as a stand-up fully enclosed large Capacity unit; insensitive to wet stroke; it is a positive pressure operation, and there is no problem of external air intrusion and corrosion.

Disadvantages: The price is higher than that of the piston type; the single unit capacity is smaller than that of the centrifugal type, and the speed is lower than that of the centrifugal type. The lubricating oil system is more complicated, and the oil consumption is large. high.

2. Centrifugal chiller

Advantages: high speed of impeller, large air volume, large capacity of single machine; few wearing parts, reliable operation, compact structure, stable operation, low vibration, low noise; small weight index per unit cooling capacity; no lubricant oil mixed in refrigerant , The heat transfer performance of the evaporator and the condenser is good. Disadvantages: Single-stage compressors will have a “surge” phenomenon at low load, and run smoothly at full load; strict requirements on material strength, machining accuracy and manufacturing quality; when the operating conditions deviate from the design conditions, the efficiency drops rapidly, The cooling capacity decreases faster than the piston type with the decrease of the evaporating temperature; in the centrifugal negative pressure system, the outside air is easy to intrude, and there is a danger of chemical changes and corrosion of the pipeline.

3. Lithium bromide absorption chiller (steam, hot water and direct combustion type)

Advantages: few moving parts, low failure rate, stable movement, small vibration, low noise; simple processing, easy operation, 10% stepless adjustment can be achieved; lithium bromide solution is non-toxic and has no damaging effect on the ozone layer; waste heat can be used. Waste heat and Other low-grade thermal energy; low operating cost, good safety; using thermal energy as power, less electrical energy consumption. Disadvantages: The service life is shorter than that of the compression type; the power saving is not energy-saving, the steam consumption is large, and the thermal efficiency is low; the unit operates in a vacuum for a long time, and the outside air is easy to intrude. and inconvenience to use. The exhaust heat load of the unit is larger than that of the compression type, and the requirements for the quality of the cooling water are higher. Lithium bromide solution is strongly corrosive to carbon steel, which affects the life and performance of the unit.

4. Modular chiller

Advantages: It is an improved type of piston chiller and screw chiller, which is composed of multiple chiller units; the unit is small in size, light in weight, low in height, and occupies a small area; simple installation, no need to reserve installation holes, On-site combination is convenient, especially suitable for renovation projects. Disadvantages: The price is more expensive; the number of modules should generally not exceed 8.