How cold are reefer containers?

refrigerated shipping container

Reefer containers, a.k.a refrigerated containers, are a perfect solution for transporting cargo which must be kept at a specific temperature. They are not just for keeping goods cold, as they can maintain temperatures in a range both below and above zero.  Here we take a closer look at how far their impressive range of practicality can actually stretch. 

reefer temperature

Going against a common misconception, reefer containers are actually able to keep cargo warm as well as cold. In general they can maintain temperatures within the range of -65˚C to 40˚C, depending on the model and manufacturer. Common models can attain a smaller range (-25˚C to + 25˚C). This makes them suitable for a wide range of temperature sensitive cargo, from fresh produce to hazardous chemicals and more.

The introduction of refrigerated containers has affected the global consumer market considerably. Perishable goods can be transported on long distances via rail, road or ship, allowing for countries to have access to fresh produce all year round, no matter the conditions of their local climate. 

Although the actual temperature regulation unit is self contained in reefer containers, for the majority of the time they require access to power. On land based sites and container vessels, electrical outlets known as reefer points are common place. When access to a reefer point is not available, diesel powered generators can be employed to keep power supplied over long distances.

Standard refrigeration units function by ventilating warm air away from the container (or feeding it in). They distribute cold air from the bottom up, via a customised 'T'-shaped decking. When the area in which the container is stored in doesn't have flowing air around it, for example in the hold of a ship, water cooling systems can also be used to cool the air being excreted. They are however expensive and their use is declining in the global freight industry. 

As with any mechanical object, reefer containers can sometimes fail. As well as being a potential for wastage of large loads of fresh produce through spoiling, it could also be particularly dangerous. Selected chemicals become volatile at certain temperatures, therefore it imperative to keep them at a steady temperature.

In order to minimise this risk, some shipping containers are fitted with redundant refrigeration systems. This is where reefers are fitted with back up refrigeration units to kick in should the primary one malfunction, as well as generators should the power become disconnected.

Reefers tend to come in either 20 foot or 40 foot variations. The insulation installed around the container walls makes their internal dimensions marginaly smaller than standard ISO container dimensions (which can be seen here). The insulation is effective in temporarily restricting temperature fluctuations, so non functioning reefers can still be put to use. It is possible to by used reefer containers, making them even more cost effective for large and small companies alike.

It is worth keeping in mind that Reefers are not designed to chill cargo. More so, they are designed to maintain its temperature. Therefore, cargo which must be kept cold should be pre chilled before being loaded into a refrigerated container.

refrigerated container confoot

Mounting a reefer on ConFoot legs only extends its practicality further. ConFoot shipping container legs can support a reefer weighing up to 30 tonnes for an indefinite period of time. They also act as a low-cost and lightweight method to remove and replace a container on a truck chassis. This combination creates a cost effective, industrial scale refrigerator, with many use possibilities for markets, supermarkets, restaurants and food distributors. To find more information about ConFoot legs click here to go the main site. Also, if you are interested in other variations of the standard shipping container, check out our guide to the different types of containers.