Ever wondered how salmon from Norway stays fresh as it makes its way to your favorite sushi restaurant in Asia? Or how apples from South Africa remain crisp despite having traveled more than 10,000 kilometers by sea?
The answer lies in refrigeration. Refrigerated — or reefer — containers are cargo containers with built-in refrigeration units that maintain the temperature of chilled or frozen goods. Perishable or seasonal products, from fruits to pharmaceuticals, are transported in reefer containers to people around the world, at any time of the year.
To keep their contents cool, reefer containers depend on an external power supply, which is usually provided by ports, container ships or freight trains.
Using this power, reefers pass chilled air through their cargo to remove excess heat. For frozen goods, reefers circulate air around the cargo to insulate the goods from heat. This allows reefers to maintain temperatures as low as -65˚C.
Besides keeping cargo cold, reefers can also keep contents warm at up to 40˚C if needed. This allows reefers to carry dangerous goods, such as chemical products, that must be maintained at specific temperatures.
To safeguard their contents in case of power failure, reefers are often fitted with backup diesel generators to keep the air flowing should the primary systems malfunction.
Find out more about DHL's ocean reefer container service here.