What is the cause of frost formation of the compressor in the low temperature refrigeration system?

What is the cause of frost formation of the compressor in the low temperature refrigeration system?

Causes of frosting:

1. Refrigerant is insufficient. After the lack of refrigerant, the evaporation temperature of the LX -25°C ~ +30°C 재순환 냉각기 is low. When the evaporation temperature is lower than zero, frost will form on the evaporator fins. The frost layer will affect ventilation, making the heat exchange effect of the evaporator poor. The refrigerant cannot evaporate completely and flows into the return pipe and compressor to continue evaporation. Therefore, frost will form on the compressor and the return pipe.

2. The drying filter is partially blocked. Blocking the filter will reduce the refrigerant supply. The evaporation temperature of the chiller is low, and frost will form on the evaporator fins. The refrigerant cannot evaporate completely and will continue to evaporate in the return pipe and compressor. Therefore, frost will form on the compressor and return pipe.

3. The expansion valve is too small or blocked. It will reduce the liquid supply of refrigerant, the evaporation temperature of the chiller is low, and frost will form on the fins of the evaporator. The refrigerant cannot evaporate completely and will continue to evaporate in the air return pipe and compressor. Therefore, frost will form on the compressor and air return pipe.

4. Poor ventilation of the chiller. The heat exchange effect of the evaporator is poor, and the refrigerant cannot evaporate completely and flows into the air return pipe and compressor to continue to evaporate. Therefore, frost forms on the compressor and air return pipe.

5. There are dead bends and dents on the liquid supply pipeline. The refrigerant supply will be reduced, the evaporation temperature of the chiller will be low, the evaporator fins will be frosted, and the refrigerant will not evaporate completely and flow into the return pipe and compressor to continue to evaporate, so the compressor and return pipe will be frosted.

6. The air filter is too dirty. The cooling water machine is poorly ventilated, the heat exchange effect of the evaporator is poor, and the refrigerant cannot evaporate completely and flows into the return pipe and the compressor to continue to evaporate. Therefore, frost forms on the compressor and the return pipe.

Because the humidity in the air is the highest at this time, and the water vapor content is the highest; Under low temperature conditions, such as below – 15 ℃, the relative humidity in the air is low, so frosting is not very serious.

How often do I need to defrost?

1) This should take into account the type and humidity of the stored products, the frequency of personnel walking in the cold storage room, the number of times they open the door every day, ventilation, air humidity and other factors.

2) Defrost as frequently as possible and as soon as possible to avoid being too late.

3) If the defrosting time is too short to melt all the ice, more ice will be produced.