The defrosting of the cold storage is mainly due to the frost on the surface of the evaporator in the cold storage, which reduces the humidity in the cold storage, hinders the heat conduction of the pipeline, and affects the cooling effect.
1. Hot air defrosting
Directly pass the hot gaseous condensing agent into and flow through the evaporator, and when the temperature of the cold storage rises to 1°C, turn off the compressor. The temperature of the evaporator rises, causing the frost layer on the surface to melt or peel off;
Hot air defrosting is economical and reliable, easy to maintain and manage, and its investment and construction are not difficult. However, there are many solutions for hot gas defrosting. The usual method is to send the high-pressure and high-temperature gas discharged from the compressor to an evaporator to release heat and defrost, and let the condensed liquid enter another evaporator to absorb heat and evaporate into low-temperature and low-pressure gas. Return to the compressor suction to complete a cycle.
2. Spray water for frosting
Water spray defrost: spray water regularly to cool the evaporator to prevent the formation of frost layer; although water spray defrost has a good defrosting effect, it is more suitable for air coolers, but it is difficult to operate for evaporator coils.
Also spray the evaporator with a solution with a higher freezing point such as 5% — 8% concentrated brine to prevent the formation of frost.
Advantages: This scheme has high efficiency, simple operation procedure, and small fluctuation of storage temperature. From the perspective of energy, the cooling consumption per square meter of evaporation area can reach 250-400kj. Frosting by water can also easily cause fogging in the warehouse, causing water dripping from the ceiling of the cold room and reducing the service life.
3. Electric defrosting
The electric heater heats defrosting. Although it is simple and easy to implement, according to the actual structure of the bottom of the cold storage and the use of the bottom at that time, the construction difficulty of installing the heating wire is not small, and the failure rate in the future is relatively high, the maintenance management is difficult, and the economy is also poor.
4. Mechanical defrosting
There are many defrosting methods for cold storage. In addition to electrical defrosting, water spray defrosting and hot air defrosting, there are also mechanical defrosting. Mechanical defrosting is mainly using tools to manually defrost. When clearing, because there is no automatic defrosting device in the design cold storage, it can only be defrosted manually, but it is very inconvenient.
Cause Analysis of Excessive Frost
During the daily use of the cold storage, it is necessary to regularly remove the frost on the cold storage. Too much frost on the cold storage is not conducive to the normal use of the cold storage. What are the commonly used techniques? the
1. Check the refrigerant, check whether there are bubbles in the sight glass? If there are bubbles, it means insufficient, add refrigerant from the low-pressure pipe. the
2. Check whether there is a gap in the cold storage board near the frost discharge pipe, resulting in leakage of cooling capacity. If there is a gap, seal it directly with glass glue or foaming agent. the
3. Check whether there is leakage at the welded part of the copper pipe, spray leak detection liquid or soapy water, and check whether there are bubbles. the
4. The reason of the compressor itself, such as high and low pressure gas leakage, needs to replace the valve plate and send it to the compressor maintenance department for repair. the
5. It depends on whether it is pulled near the return air. If it is, check for leaks and add refrigerant. the
In this case, the pipe is not placed horizontally, and it is recommended to level it with a level. Then there is not enough refrigerant charge, it may be that it is time to add refrigerant, or there is ice blockage in the pipe.
Post time: Mar-27-2023