In the transportation of frozen and refrigerated food in large supermarkets, refrigerated trucks must be used as carriers. During transportation, the temperature of the refrigerated truck container will be unstable. Today we will analyze the reasons for you.
1.The refrigerated truck has poor heat insulation or sealing performance;
Poor thermal insulation performance is due to the lack of adhesion between the inner and outer skins of the compartment or the insufficient thickness of the thermal insulation layer, resulting in poor thermal insulation and thermal insulation effects. It is mainly caused by improper selection of the thickness of the thermal insulation layer during design or poor quality of thermal insulation materials during construction. In addition, during the construction and use process, the thermal insulation and moisture-proof performance of the thermal insulation material may be damaged, causing the insulation layer to be damp, deformed, or even eroded, and its thermal insulation ability is reduced, the cooling loss of the refrigerated truck body will increase, and the temperature of the refrigerated truck body will drop significantly. Slow down. Another important reason for the large cold loss is the poor sealing performance of the compartment, and more hot air enters the compartment from the leak. Generally, if condensation occurs at the sealing strip of the compartment door or the insulation wall of the compartment, it means that the seal is not tight. In addition, frequent opening and closing of the door of the refrigerated truck body or more people entering the refrigerated truck body together will increase the cold loss of the refrigerated refrigerated truck body. Try to avoid opening the door of the refrigerated truck body to prevent a large amount of hot air from entering the refrigerated truck body. Of course, when the refrigerated refrigerated truck body is frequently stocked or the stock is too large, the heat load increases sharply, and it generally takes a long time to cool down to the specified temperature.
2. The surface of the evaporator is too thick or dusty;
Another important reason that causes the temperature of the compartment to drop slowly is the low heat transfer efficiency of the evaporator, which is mainly caused by the thick layer of frost or excessive dust on the surface of the evaporator. Since the surface temperature of the evaporator of the compartment is mostly lower than 0℃, and the humidity of the compartment is relatively high, the moisture in the air is very easy to frost or even freeze on the surface of the evaporator, which affects the heat transfer effect of the evaporator. In order to prevent the frost layer on the surface of the evaporator from being too thick, it needs to be defrosted regularly. There are two defrosting methods, as follows:
① Shut down and defrost. That is, stop the operation of the compressor, open the door of the compartment, and allow the temperature of the compartment to rise, and restart the compressor after the frost layer automatically melts.
② Frost. After removing the goods in the compartment, directly flush the surface of the evaporator pipe with hot tap water to dissolve or fall off the frost layer. In addition to thick frost formation, the heat transfer effect of the evaporator will be poor. The heat transfer efficiency of the evaporator will also be significantly reduced due to excessive dust accumulation on the surface of the evaporator due to long-term uncleaned.
