Refrigeration units are used to maintain the temperature of goods, preserving their original freshness. Therefore, truck owners should not mistakenly believe that refrigeration units in refrigerated trucks simply lower or heat the temperature of goods. This misconception leads to incorrect use of the refrigeration unit, reducing its lifespan.

The function of a refrigerated truck's refrigeration unit is similar to wrapping goods in blankets for sale in the past—preventing the exchange of hot and cold air with the outside air, which could cause spoilage.

When loading a refrigerated truck, the cargo compartment must first be pre-cooled or pre-heated. The refrigeration unit must be turned off during loading and unloading. There are a few details to note regarding refrigeration units in refrigerated trucks:

This is because after pre-cooling the cargo compartment, if the unit is not turned off, opening the refrigerated container door will cause the evaporator fan of the refrigeration unit to operate. The front of the fan creates positive pressure, while the back creates negative pressure. Therefore, cold air blows out from the top of the compartment, while hot outside air is quickly drawn in from the bottom, causing the temperature inside the compartment to rise rapidly.

If the fan is turned off before loading and unloading, the air circulation is interrupted because the fan is in a discontinuous state, and the air pressure inside and outside the carriage is the same, which slows down the speed at which hot air from outside enters the carriage.