Common problems with cold storage

Common problems with cold storage

1.Installation environment and maintenance issues of air coolers. The location and environment of the air cooler inside the cold storage will affect its operation. Generally, the air cooler near the cold storage door is prone to condensation and frost. Although the air cooler can automatically heat and defrost at regular intervals, if the door is opened too frequently, the opening time is too long, and the hot air flow enters for a long time and in large quantities, the defrosting effect of the fan will be poor. Because the defrosting time of the air cooler cannot be too long, otherwise the cooling time will be relatively shortened, the cooling effect will be poor, and the storage temperature cannot be guaranteed.

2.The drainage problem of melted water during defrosting of the air cooler. This issue is related to the severity of frost formation. Due to severe frost formation in the fan, a large amount of condensate water will inevitably be generated. The fan's water collection tray cannot withstand it, and the drainage is not smooth, which will leak out and flow to the ground inside the warehouse. If there are stored goods below, they will soak the goods. In this case, thicker guide pipes can be installed to remove condensate.

Some air coolers have the problem of blowing water from the fan and spraying it onto the inventory in the warehouse. This is also a problem of fan frost formation in hot and cold exchange environments, mainly due to the condensation water generated by the fan blades in the hot environment, rather than the defrosting effect of the fan itself.

3.The issue with the condenser fan motor and the heating pipes of the cooling fan. This is a vulnerable component. Fan motors that run for a long time in high temperature environments may malfunction and be damaged. If ensuring temperature in the cold storage is crucial, it is necessary to order some vulnerable parts for timely repair.

4.Cold storage temperature and cold storage door issues. The size of a cold storage room, the amount of inventory, the number of doors opened, the time and frequency of opening and closing doors, the frequency of inventory entry and exit, and the throughput of goods are all factors that affect the temperature inside the warehouse.

The design and construction of cold storage, as well as the setting and quantity of cold storage doors, must be comprehensively arranged based on inventory levels and the frequency of door opening and closing. Cold storage units should also use cold storage in a reasonable manner according to design specifications, and cannot ignore design conditions and the actual condition of facilities, blindly increasing inventory and improving goods turnover, exceeding the normal load and bearing capacity of facilities and equipment. Otherwise, many problems will arise.

5.Fire safety issues in cold storage. Cold storage is generally around minus 20 degrees Celsius, and due to the low ambient temperature, it is not suitable to install fire sprinkler systems. Therefore, more attention should be paid to fire prevention in cold storage. Although the ambient temperature of a cold storage is low, if a fire occurs, there may be combustible materials in the warehouse, especially inventory that is often packaged in cardboard and wooden boxes, which can easily ignite. Therefore, the fire hazard of cold storage is also very high, and smoking and fire must be strictly prohibited in cold storage. At the same time, the air cooler and its electrical box, power cord, and electric heating tube should also be regularly inspected to eliminate electrical fire hazards.

6.The environmental temperature issue of the condenser. The condenser is generally installed on the roof of outdoor buildings. In high summer temperatures, the temperature of the condenser itself is very high, which increases the operating pressure of the unit. If there are many hot weather conditions, a cooling shed can be added on the roof condensation to block sunlight and lower the temperature of the condenser, in order to reduce machine pressure, protect unit equipment, and ensure the temperature of the cold storage. Of course, if the unit's capacity is sufficient to ensure the temperature of the warehouse, it is also possible not to build a cooling shed.

7.The problem of low compressor efficiency. Due to long-term operation of the compressor, the cylinder liner and piston rings and other components are severely worn, resulting in increased clearance and a corresponding decrease in sealing performance. As a result, the gas transmission coefficient of the compressor also decreases, leading to a decrease in refrigeration capacity. The refrigeration capacity of the compressor can be roughly determined by observing its suction and discharge pressures. If the refrigeration capacity of the compressor decreases, the common method is to replace the cylinder liner and piston rings of the compressor.

8.There is a problem of excessive air or refrigeration oil in the evaporator of the cold storage. Once a large amount of refrigeration oil is attached to the inner surface of the heat transfer tube of a cold storage evaporator, its heat transfer coefficient will decrease. Similarly, if there is more air in the heat transfer tube, the heat transfer area of the evaporator will decrease, and its heat transfer efficiency will also significantly decrease, slowing down the rate of temperature drop in the warehouse. Therefore, in daily operation and maintenance, attention should be paid to timely cleaning the oil stains on the inner surface of the evaporator heat transfer tube and discharging the air inside the evaporator.

9.Improper adjustment or blockage of the throttle valve in the cold storage, as well as problems with excessive or insufficient refrigerant flow. When the throttle valve is opened too large, the refrigerant flow rate is too high, and the evaporation pressure and temperature also increase, and the rate of temperature decrease in the warehouse will slow down; At the same time, when the throttle valve is opened too small or blocked, the refrigerant flow rate also decreases, the cooling capacity of the system also decreases, and the rate of temperature drop in the warehouse will also slow down.

Generally, the refrigerant flow rate of the throttle valve can be determined by observing the evaporation pressure, evaporation temperature, and frost formation in the suction pipe.

Blockage is an important factor affecting refrigerant flow, and the main causes of throttle valve blockage are ice blockage and dirt blockage.

Ice blockage is caused by the poor drying effect of the dryer, as the refrigerant contains water. When passing through the throttle valve, the temperature drops below 0 ℃, and the water in the refrigerant freezes into ice, blocking the throttle valve hole.

Dirty blockage is caused by the accumulation of a large amount of dirt on the inlet filter screen of the throttle valve, which hinders the flow of refrigerant and leads to blockage.