Defrosting measures of cold storage air cooler

        Artificial and frost：The method that the operator removes the condensation frost directly on the surface of the evaporator with a cleaning tool is called manual cleaning frost. Generally, it is only suitable for the defrosting of wall and top pipe of frozen goods refrigerated storage. Freeze refrigerated room are long-term inventory of refrigerating room, exhaust pipe in the surrounding the cargo at the top or close to, if use hot gas defrosting or electric heating defrosting, the melting of the cream will not only make the goods be affected with damp be affected with damp, also the item the stick into pieces, and library temperature recovery in food storage quality, can be damaging to congelation refrigeration row between the tube is so unfavorable adopted the practice of "harmony" frost defrost, Water defrosting is even more unacceptable. The characteristic of artificial frost is that the frost does not melt, and the evaporator can also work normally in the defrost process, which basically does not affect the constant temperature of the warehouse, so it is the most suitable for the defrost of the row pipe of the frozen goods refrigerated room. However, when defrosting, personnel need to enter the warehouse for operation, the working conditions are poor, and it is necessary to increase the amount of heat and cold consumption and labor costs.

        Manual defrosting also has a balance between labor costs and operating costs. Since the variety of the refrigeration plant is stored goods are different, the packing is different also, exhaust pipe of the frosting rate difference is very big, so artificial defrost intervals can only according to their own specific circumstances to determine, science, it is the frost layer thickness for the operation of the system increase electricity and comprehensive analysis and comparison of deicing labor to set a reasonable economic defrost cycle. The specific analysis idea is that in a reasonable defrosting cycle the thermal resistance of frost layer caused by the cumulative number of additional operating costs is exactly equal to a defrosting labor costs.

        Glycol frost：In the cold storage, the glycol is heated and stored in the storage tank by the heat generated by the compressor exhaust through the heat exchanger. The glycol is pumped into the evaporator to be defrosted (air cooler, aluminum exhaust pipe), and the normal night supply and liquid return valves are closed at the same time. When the evaporator temperature rises, the evaporator surface of the frost layer melt or peel off; The pre-cold storage adopts the way of hot gas defrost, which sends the high pressure and high temperature gas discharged from the compressor into the evaporator to release heat and defrost. This defrost way is economical and reliable, convenient maintenance and management, and its investment and construction are not difficult.

        Electric defrost：Electric heating defrost is to use the electric heating tube arranged in the air cooler to heat the fin to melt the frost layer. This method is simple in system and more convenient in operation. However, each square heat exchange area of the cooling fan is about 40~100W electric heating tube, which consumes too much power and has a great influence on the fluctuation of storage temperature, so it is not energy-saving. The power of electric defrosting heating tube is very large, the quality of heating tube is not good or the use of a long time, easy to burn out or even cause fire, electric defrosting has serious safety risks.

         Water defrosting：Water defrosting is a method of using water pump or water spray device to spray water to the outer surface of evaporator, so that the frost layer is melted by the heat of water and washed away. Water defrosting is a very effective defrosting method with simple operation and short time. In the cold storage of very low temperature, after repeated defrosting, the water temperature is too low, will affect the effect of defrosting; If the frost is not washed out within the set time, the frost layer may turn into ice after the cooler works properly, making the next defrosting more difficult.

        The hot working medium defrosts：Defrosting of thermal working medium is to use the superheated refrigerant vapor with high temperature discharged from the compressor to enter the evaporator after passing through the oil separator. The evaporator is temporarily used as a condenser, and the heat released by the condensation of thermal working medium 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 defrosting discharge tank or low-pressure circulating tank by means of thermal working medium pressure or gravity. During hot air defrosting, the load of the condenser is reduced, and the operation of the condenser can also save part of the electric energy. It can be seen that hot working medium defrosting is the most economical way of defrosting air cooler.

        At present, the barrel pump liquid supply system because of the increase of many auxiliary equipment, and the increase of the auxiliary equipment, so that the investment cost increases, is only applied in large systems. The majority of medium and small cold storage in the market, using freon easy to realize the advantage of automatic control, the use of direct expansion of liquid supply and discharge barrels for hot fluorine defrosting is of great promotion value.

        The basic principle of： Use the hot freon steam from the compressor to heat and defrost the air cooler. After defrosting, freon liquid is discharged into the discharge tank, and then pressurized to make the freon supply and liquid supply pipe in the discharge tank participate in refrigeration. During defrosting, the drain flow is in the same direction as in the refrigeration cycle.