Refrigerated containers, also called reefers, are designed for the intermodal transportation of temperature sensitive cargo. To refrigerate their cargo, they use an integrated refrigeration unit that runs on external power. When located on land, a quay, or on a ship, the unit is powered from power sources called reefer points. When being transported by rail or truck, refrigerated containers are powered by diesel generators, or gensets. They are capable of temperature control ranges from as cold as -65ºC (-85ºF) up to 40ºC (104ºF), and are generally available only in 6 meter (20ft) and 12 meter (40ft) lengths. These units are ideal for transporting fresh produce and food products.
To preserve optimal quality, fresh produce requires precise temperature control during shipping. If the temperature is too cold, the produce can partially freeze, damaging it. Too warm, and fresh produce quality quickly degrades. Frozen foods also require precise temperature control, especially quick-frozen foods. If quick-frozen foods aren’t kept frozen at a cold enough temperature, frost forms on the food product, drying it out and degrading overall quality. Some fresh produce and plants, however, require warmer temperatures to maintain optimal quality.
For optimal reliability, refrigeration containers are often equipped with two systems. One system functions as the primary system while the second system acts as a backup should the primary system fail. To ensure refrigeration is maintained, regardless of circumstances, most units are outfitted with one or more diesel gensets. Backup gensets may be required for transporting certain hazardous materials and other dangerous goods.
Integral Refrigeration Temperature Control
Integrated units circulate supply chilled air to the cargo area while returning the warmer air to the system for chilling and recirculation. Floors are designed for maximum airflow around cargo to maintain even cooling. Corrugated inner walls help circulate air by providing channels for the air to follow.
Loading Requirements for Refrigerated Containers
When loading cargo in a refrigerated or insulated containers, it is important to follow loading guidelines. These guidelines provide detailed information about how to properly load cargo on them for optimal cooling efficiency. Failing to follow these guidelines will may lead to cargo damage.
When loading frozen or refrigerated, packaged cargo, it is important to note if the cargo is at the correct temperature at the time of loading, or if it is too warm. Also, care must be taken to ensure that the outside supply air opening is closed, as this can have an adverse effect on cooling. If the outside air supply opening is not completely closed, the refrigeration unit may work too hard at cooling, causing the evaporator to ice up. Once the evaporator is covered in ice, it can no longer cool the air, and the cargo will continue to get warmer.
Fresh produce often requires a certain amount of outside air to circulate in the container during shipment so that produce such as lettuce and fresh herbs, can continue respiration. If outside air vents are closed, gases given off by the plants, such as ethylene gas, can promote spoilage during transit.
Repurposing Refrigerated Containers
Used refrigerated containers make for an affordable, easy way to add additional cooler or freezer space to foodservice operations. For events that require on-site refrigeration, hiring a refrigerated unit may be an affordable solution, providing convenient cold and/or frozen storage capacity for banquets, outdoor events, and filming of movies.
A Global Food Shipment Revolution
The refrigerated container revolutionized food shipment by making it possible for year-round shipment of fresh and frozen food products from every part of the world. As appetite grows for authentic cuisines from all over the globe, refrigerated container use will spread. With high reliability and efficiency, it is now possible to ship virtually any produce from field to table in a few days using refrigerated containers.