refrigerated container 20 ft

the description
The refrigeration unit is arranged in such a way that the outer dimensions of the container conform to ISO standards and then fit into the container vessel cell guides, for example. Having an integrated refrigeration unit implies a loss of internal volume and load.
When transported by ship, the integrated units must be connected to the on-board power supply system. The number of reefer containers that can be connected depends on the capacity of the ship's power supply system. If the said capacity is too low for refrigerated containers to be transported, "power packs" can be used, which are equipped with relatively large diesel generators and meet ISO requirements regarding 20 inch container dimensions. When in the container, the containers connect to the terminal's power supply system. For transportation by road and rail, most of the integrated unit refrigeration units are powered by a generator set (generator set). This may be either a component of the refrigeration unit or connected to the refrigeration unit.
Air flows through the container from bottom to top. Generally, "warm" air is drawn from inside the container, cooled in the refrigeration unit and then blown back into the container as cold air.
To ensure adequate circulation of cold air, the floor is provided with grids. Pallets create additional space between container floor and cargo, thus also forming a satisfactory airflow channel. In addition, the side walls of the container are "corrugated", which ensures satisfactory airflow there as well.
In the upper area of ​​the container, adequate space (at least 12 cm) must be provided for airflow. For this purpose, while packing the container, enough free space should be left above the cargo. The maximum load height is placed on the side walls.
To ensure vertical airflow from bottom to top, the packaging must also be appropriately designed and the load should be charged in a reasonable manner.
In addition to regulating the temperature, the integrated units also allow a controlled exchange of fresh air, for example to remove metabolic products such as CO2 and ethylene if the fruits are transported.
In refrigeration units, both the supply and return air temperature are measured, and depending on the operating mode, one of these values ​​is used to control the cold air. Temperature measurement can be performed in various ways. The Partlow recorder generally records the temperature of the return air, as this provides an indication of the condition or temperature of the charge. Data loggers are increasingly being used, which digitally detect the temperature and indicate it on the display. Once transferred to a computer, the data may then be evaluated.
The temperature monitor is attached to the outside of the refrigeration unit, so that unit operation can be checked at any time.
Digital or analog recorders may also be placed directly into the shipment, to measure the temperatures inside the container. The recorder must be accommodated in such a way that temperatures are recorded at the hazard points of the container (inside the package, the upper layer at the end of the door).