Why do cold storages need to be defrosted? How to defrost? Dec 13, 2021
1. Overview:

As the surface of the cooler evaporator in the cold storage is frosted, it hinders the conduction and dissipation of the cold capacity of the refrigeration evaporator (pipe), and ultimately affects the cooling effect. When the thickness of the frost layer (ice layer) on the surface of the cooler evaporator reaches a certain level, the refrigeration efficiency even drops below 30%, resulting in a large waste of electricity and shortening the service life of the refrigeration system. Therefore, it is necessary to perform cold storage defrosting operations within an appropriate period.

2. Purpose of defrosting:
1). Improve system refrigeration efficiency;
2). Guarantee the quality of frozen in the warehouse;
3). Save electric energy;
4). Extend the service life of the cold storage system.

 cooler evaporator
3. Defrosting method:
Cold storage defrosting methods: hot gas defrosting (hot fluorine defrosting, hot ammonia defrosting), water spray defrosting, electrical defrosting, mechanical (manual) defrosting, etc.
1). Hot gas defrosting-suitable for large, medium and small cold storage pipe defrosting:
The hot, high-temperature gaseous condensate directly enters the evaporator without interception, the temperature of the cooler evaporator rises, and the junction between the frosting layer and the cold row is melted or peeled off. Hot gas defrosting is economical and reliable, maintenance and management are convenient, and its investment and construction are not difficult.
2). Water spray defrosting-mostly used for defrosting large and medium-sized Water defrosting cooler evaporator:
Regularly spray and cool the water defrosting cooler evaporator with room temperature water to melt the frost layer. Although water spray defrosting has a good defrosting effect, it is more suitable for water defrosting cooler evaporators, and it is difficult to operate for evaporative coils. It is also possible to spray the evaporator with a solution with a higher freezing temperature, such as 5% to 8% concentrated brine, to prevent the formation of frost.

Water defrosting cooler evaporator

3). Electric heating defrosting-electric heating tubes are mostly used for medium and small electrical defrosting eavporators:
Electric heating wire is mostly used for electric heating and defrosting of aluminum tube in small and medium-sized cold storage. It is simple and easy to use for electrical defrosting eavporators. However, for aluminum tube cold storage, the construction difficulty of installing electric heating wire on aluminum fins is not small, and In the future, the failure rate is also relatively high, the maintenance and management are more difficult, the economy is also poor, and the safety factor is relatively low.

Electrical defrosting eavporators

4). Mechanical manual defrosting——Applicable for small cold storage pipe defrosting:
Manual defrosting of cold storage pipes is more economical and the most primitive defrosting method. It is unrealistic to use manual defrosting for large cold storages. It is difficult to operate with the head up, and the physical energy is consumed too quickly. Too long staying in the warehouse is harmful to health, and the defrosting is not easy to complete, which may cause deformation of the evaporator, or even damage the evaporation A refrigerant leakage accident occurred due to the device.

Defrosting method of cooler evaporator:
(1) There are electric heating tube defrosting and water frosting to choose from. In areas where water is more convenient, you can choose water defrosting cooler evaporator, while water shortage areas prefer electrical defrosting eavporators.

(2) The electric heating tube defrosting is mostly used in the defrosting of small air coolers; the water flushing air coolers are generally configured in large air-conditioning and refrigeration systems.

Bitzer Condensing Unit

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