Reasons for unstable temperature of refrigerated truck cargo box

Reasons for unstable temperature of refrigerated truck cargo box

In the transportation of frozen and refrigerated food in large supermarkets, refrigerated trucks must be used as carriers. In order to ensure the freshness or shelf life of the goods, the temperature control of the cargo compartment is extremely critical during the transportation of refrigerated trucks. During certain transportation, there will be situations where the temperature is required to drop rapidly. Next, the manager of Chengli refrigerated truck manufacturer Xu will explain to you the analysis of the unstable temperature of the refrigerated truck container:

Many users will have a certain amount of distress at this time, and the temperature of the refrigerated truck's cargo compartment will drop and there will be a trend of full replacement. How to troubleshoot and solve this kind of problem?

1. The refrigerated truck has poor heat insulation or sealing performance;

　　 Poor thermal insulation performance is caused by the lack of adhesion between the inner and outer skins of the compartment or the insufficient thickness of the thermal insulation layer, which results in poor thermal insulation and thermal insulation. 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 decreases, and the cooling loss of the car body increases accordingly, and the temperature of the car body drops significantly. Slow down. Another important reason for the large cold loss is the poor sealing performance of the car body, and more hot air enters the car from the leak. Generally, if condensation occurs at the sealing strip of the compartment door or the sealing part of the compartment heat insulation wall, it means that the seal is not tight. In addition, frequent opening and closing of the door of the car body or more people entering the car body at the same time will also increase the cold energy loss of the refrigerated car body. Try to avoid opening the door of the car body to prevent a large amount of hot air from entering the car body. Of course, when the refrigerated car 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 for the slow drop in the temperature of the compartment 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 evaporator from being too thick, it needs to be defrosted regularly. There are two defrosting methods, as follows:

　　①Shut down and defrost. That is, stop the operation of the compressor, open the door of the car body, and let the temperature of the car body rise, and restart the compressor after the frost layer automatically melts.

　　②Frost. After moving the cargo out of 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 excessively thick frosting will lead to poor heat transfer effects of the evaporator, the evaporator surface has too thick dust due to long-term uncleaned, and its heat transfer efficiency will also be significantly reduced.