In order to maintain the normal operation of the refrigeration equipment inside the refrigerated container, ensure the predetermined freezing temperature inside the vehicle, and save energy, the refrigeration unit system inside the refrigerated compartment should consider defrosting of the evaporator, which is an important characteristic that distinguishes the refrigeration system of refrigerated trucks from other automotive air conditioning refrigeration systems. In addition, structurally, the spacing between the fins of the evaporator should be appropriately increased to increase the defrosting time interval and reduce temperature fluctuations inside the vehicle.

The cab of refrigerated transport vehicles should be equipped with air conditioners to change the working environment of drivers, improve work efficiency, and ensure driving security. This forms a parallel connection where the refrigeration and cabin air conditioning units share a compressor and condenser, and separate two sets of evaporators and their controls.

Two evaporators are controlled by solenoid valves to regulate their flow direction. One evaporator is installed at the front end of the refrigerated truck with a relatively low evaporation pressure and is used for refrigeration. The other evaporator is installed in the cab and is controlled by an evaporation pressure regulating valve to increase the evaporation pressure and serve as an air conditioner.

The vast majority of small and medium-sized refrigerated trucks have non independent refrigeration systems. The cabin air conditioner and the refrigeration compartment share a compressor driven by the main engine and run two evaporators in parallel.

Refrigerated trucks include vapor compression refrigeration trucks, frozen plate refrigeration trucks, ice cold refrigeration trucks, and dry ice and liquid nitrogen refrigeration trucks.

Refrigerated transport vehicles mainly transport fresh fruits, vegetables, poultry, eggs, meat and other food products. The refrigeration system needs to work at low temperatures. Generally, when transporting cooled and frozen meat products, the evaporation temperature of the refrigerant is between -5-20 ℃, and the surface temperature of the evaporator is below O ℃.

Refrigerated goods always contain some amount of water vapor in the middle, so the evaporator inside the container often works with frost.