The frosting of the cold storage refrigeration evaporator should be comprehensively analyzed from many aspects, and the design of the evaporator, the fin spacing of the evaporator, the pipe layout, etc. should be optimized as a whole. The main reasons for the serious frosting of the cold storage air cooler are as follows:
1. The maintenance structure, moisture-proof vapor barrier layer, and thermal insulation layer are damaged, causing a large amount of outdoor humid air to enter the cold storage;
2. The cold storage door is not sealed tightly, the door frame or door is deformed, and the sealing strip is aged and loses elasticity or is damaged;
3. A large amount of fresh goods have entered the cold storage;
4. The cold storage is seriously exposed to water operations;
5. Frequent inflow and outflow of goods;
Four common defrosting methods for cold storage evaporators:
First: manual defrosting
During the manual defrosting process, safety is the first priority, and do not damage the refrigeration equipment. Most of the condensed frost on the equipment falls off from the refrigeration equipment in solid form, which has little effect on the temperature inside the cold storage. The disadvantages are high labor intensity, high labor time cost, incomplete coverage of manual defrosting, incomplete defrosting, and easy damage to refrigeration equipment.
Second: water-soluble frost
As the name suggests, it is to pour water on the surface of the evaporator, increase the temperature of the evaporator, and force the condensed frost attached to the surface of the evaporator to melt. Water-soluble frost is carried out on the outside of the evaporator, so in the process of water-soluble frost, it is necessary to do a good job of water flow processing to avoid affecting the normal use of the refrigeration equipment and some items placed in the cold storage.
Water defrosting is simple to operate and takes a short time, which is a very effective defrosting method. In a cold storage with very low temperature, after repeated defrosting, if the water temperature is too low, it will affect the defrosting effect; if the frost is not cleaned out within the set time, the frost layer may turn into an ice layer after the air cooler works normally, making the next defrosting more difficult.
The third type: electric heating defrost
Electric heating defrost is for equipment that uses fans for refrigeration in cold storage. Electric heating tubes or heating wires are installed inside the refrigeration fan fins according to the upper, middle and lower layout, and the fan is defrosted through the thermal effect of the current. This method can intelligently control the defrost through the microcomputer controller. By setting the defrost parameters, intelligent timed defrost can be achieved, which can greatly reduce labor time and energy. The disadvantage is that electric heating defrost will increase the power consumption of the cold storage, but the efficiency is very high.
The fourth type: hot working medium defrost:
Hot working medium defrost is to use the superheated refrigerant vapor with a higher temperature discharged by the compressor, which enters the evaporator after passing through the oil separator, and temporarily treats the evaporator as a condenser. The heat released when the hot working medium condenses is used to melt the frost layer on the surface of the evaporator. At the same time, the refrigerant and lubricating oil originally accumulated in the evaporator are discharged into the defrost discharge barrel or low-pressure circulation barrel by means of hot working medium pressurization or gravity. When hot gas defrosts, the load of the condenser is reduced, and the operation of the condenser can also save some electricity.
Post time: Feb-27-2025