What are the main characteristics of screw chiller

There are two types of evaporators used in industrial chillers.
Our chiller manufacturers generally use dry evaporators.
Screw chillers are generally equipped with shell and tube evaporators.
In the flooded evaporators, the refrigerant goes through On the shell side, the ice water goes through the tube side, in other words, the refrigerant goes outside the copper tube, and the ice water goes inside the copper tube
.

The dry evaporator is the opposite.
The refrigerant goes on the tube side, and the ice water goes on the shell side.
In other words, the refrigerant goes inside the copper tube, and the ice water goes outside the copper tube
.

Comparison of the two: 1.
In terms of working conditions and reliability, the flooded unit has many components, the circuit is complex, and the reliability of the unit is low; the dry unit has few components, the circuit is simple, and the unit operates reliably
.

Flooded units are suitable for running under constant working conditions, and changes in working conditions are easy to cause unit failures, while dry-type units can adapt to changing working conditions
.

 　　2.
Oil return performance When lubricating oil and refrigerant dissolve each other, the oil return power of the flooded evaporator is the ejector pump, which is difficult and unstable to return oil, and the oil return condition directly affects the working conditions of the unit
.

The oil return power of the dry type unit is high and low pressure difference, and the oil return is stable and convenient
.

 　　3.
Liquid filling capacity The shell of the flooded evaporator is filled with refrigerant, and the liquid filling capacity is large.
It is mostly used for open compressors with easy refrigerant leakage and some screw compressors with large cooling capacity
.

The refrigerant charge of the dry evaporator is only 1/2~1/3 of that of the flooded evaporator
.

 　　4.
Energy Efficiency The flooded unit has high energy efficiency, the same input power has a large cooling capacity, and the cooling capacity is 10%~12% larger than that of the dry unit
.

 　　5.
Cost The cost of the liquid unit is high, and the cost of the dry unit is low
.

 　　Advantages and disadvantages of flooded type Advantages: The evaporator has high heat exchange efficiency and higher energy efficiency than the dry type evaporator, and the unit with the same cooling capacity is slightly smaller than the dry type
.

 　　Disadvantages: 1.
It is necessary to add a liquid level control device or a superheat control device to ensure that the refrigerant flow entering the evaporator can maintain the liquid level at an appropriate height
.

 　　2.
The price of the liquid level control device or the superheat control device is quite expensive, maintenance and adjustment are very troublesome, and the adaptability is very poor when the unit conforms to changes
.

 　　3.
If the liquid level of the refrigerant in the evaporator decreases, the refrigerating oil in the evaporator that is compatible with the refrigerant is not easy to return to the compressor, which may cause the compressor to lose oil, which may directly lead to the burning of the compressor
.

 　　4.
If the liquid level of the refrigerant in the evaporator is raised, the refrigerant will enter the compressor in liquid form, causing liquid compression, which will also cause the compressor to burn out
.

 　　5.
The charging amount of refrigerant and refrigerating oil in the whole system is more than twice that of the dry type, and the maintenance cost in the future will increase
.

 　　6.
Because the oil return of the flooded evaporator is very troublesome, the quality requirements of the refrigeration oil are very high, and the refrigeration oil must be guaranteed to work with high quality
.

After a period of use, because the refrigeration oil will gradually thicken, it will be very difficult to return the oil, and it must be replaced immediately.
Its service cycle is shortened by more than half compared with the dry evaporator, which greatly increases the operating cost
.