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Schlee (China) Refrigerating Equipment Manufacturing Co.,Ltd

Add:Jupu Road, Pukou Development Zone, Nanjing City, Jiangsu Province, China

Contact us:Cherry





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Air Cooled Screw Chiller Working Principle
- Jun 15, 2017 -

Screw chiller is a large industrial refrigeration equipment. Widely used in central air conditioning and large refrigeration industry. Air Cooled Screw Chiller Plays an important use of refrigeration, cooling, cooling. The use of water cycle working principle, saving water resources. Direct cooling equipment with cold water. Can not rise in industrial equipment temperature. Constant equipment at low temperature.

1, screw chiller selection should be in accordance with the cold load and ready to use for what to think about. For low-load operating conditions longer cooling system, suitable for multi-head piston compressor or screw compressor unit, easy to conditioning and energy saving, that is, Air Cooled Screw Chiller we often say that the double-head screw chiller, with the Load changes, the screw chiller automatically determines the number of starts the compressor in the best working condition, thus effectively saving power.

2, the choice of screw chiller, the higher the performance factor of the higher value of the unit. According to the previous data statistics, the normal screw chillers operating under the 100% load for about a year running time of about 1/4 or less. The operating time of 100%, 75%, 50% and 25% load in the run time is roughly 2.3%, 41.5%, 46.1% and 10.1% respectively. Therefore, Air Cooled Screw Chiller in the selection of chillers should give priority to the efficiency curve of flat screw chiller model. At the same time, in the design selection should take into account the chiller unit load adjustment range, multi-head screw chiller part of the load performance is excellent, according to the actual situation of the factory selection screw chiller.

3, the choice of screw chiller, it should pay attention to the conditions of nominal conditions. The actual cooling capacity of the chiller is related to the following two points: a, cold water effluent temperature and flow; b, water inlet temperature, flow rate and dirt coefficient of cooling water.

4, the choice of screw chiller, Air Cooled Screw Chiller it should be noted that the type of screw chiller normal work areas, mainly the motor current limit is the surface operating conditions of the shaft power current value.

5, in the design of the choice of screw chiller should pay attention to: in the nominal flow conditions, the cold water outlet temperature should not exceed 15 ℃, air-cooled unit outdoor dry bulb temperature over 43 ℃. If you must go beyond the above categories, when you understand the use of the scope of the compressor can be allowed to match the power of the motor can be sufficient.

Air heat pump unit in the heating operation, when the air side of the heat exchanger fin surface temperature is lower than the air dew point temperature and below 0 ℃, Air Cooled Screw Chiller the heat exchanger surface will frost. Frosting increases the heat transfer resistance and reduces the amount of air into the heat exchanger, so that the unit heat generated attenuation. Therefore, when the frost layer reaches a certain thickness, the air side heat exchanger must be defrosted.

Air-cooled heat pump unit commonly used defrost method:

① reverse cycle defrost, the unit into the defrost program, four-way valve for the unit from the heating mode switch to defrost / cooling mode, while the air side of the heat exchanger fan shutdown;

② heat bypass defrost, the unit into the defrost program, the four-way valve is not changed, the unit is still in the heating cycle, the compressor exhaust is directly bypassed to the need to defrost the air side heat exchanger.