The liquid refrigerant is stored in big metal insulated cylinder. It really is a large thermos bottle. Sometimes they are in the front part of the cargo vehicle. Each block has temperature control, providing the temperature range 20F 60F (-29C 16C).
Temperature control temperature sensor is connected, as in the standard thermostatic control engine. As the temperature rises, the switch operating the control valve opens and liquid refrigerant enters the factory. The evaporator can be blowers, coils, plates, or eutectic plates. As liquid refrigerant passes through the plate, it evaporates. Steam flowing through the plates by the pressure difference. When the desired temperature is reached valve closes and the refrigerant. Used steam leaves the evaporator at approximately the same temperature cargo air space. Using this method, not the refrigerant mixtures with air in the passenger compartment.