Do you know how ice cream, fruits, vegetables, meat, cheese, fish, frozen foods, pharmaceuticals and chocolate are transported by sea?

Reefers, or sea refrigerated containers (RF), are used for this purpose. These containers are equipped with a refrigeration unit that is connected to the ship’s power supply, making them suitable for transporting goods that require controlled temperatures during transport.

Reefer – the history of creation

The idea for a refrigerated container originated as early as the 19th century, when many commodities, such as fruit and meat, lost their value during long sea voyages. The first experiments were conducted using ice, salt and other refrigerating substances. In 1877. Ferdinand Carré managed to transport 150 tons of frozen meat in 50 days from Sydney to Britain on a ship equipped with compression refrigeration. The first refrigerated ships, designed specifically for transporting bananas, appeared in 1901, but it wasn’t until the 1930s that the Banas Shipping Company began using special insulated containers that could be filled with ice. The real breakthrough, however, came in 1960, when the U.S. company Matson Navigation introduced the first reefers equipped with a refrigeration unit, which made it possible to control the temperature throughout the voyage. The 1970s saw the emergence of refrigerated containers designed specifically for transport by container carriers.

How does a refrigerated container work?

The refrigerated container must be connected to a power source located at the transport base, at the terminal, on board the ship or to a generator.

The task of a refrigerated container is to keep three parameters constant:

• temperature: a sizable proportion of perishable goods require specific temperature settings in order to preserve their quality during transport. Standard refrigerated containers are designed to maintain temperatures between +25°C and -25°C for chilled and frozen cargo. However, there are also some that are capable of maintaining temperatures down to -35°C or even lower – down to -70°C,
• ventilation: some goods produce gases that can lead to cargo damage -. in their case it is necessary to replace the air in the container. Goods that require ventilation levels to be set include apples, for example.
  
• humidity: since some products need to be transported at lower humidity levels in the air, the units in the reefers have a dehumidification function. The standard is a relative humidity between 60% and 85%.

Note that before loading, the goods must be cooled to the required temperature to guarantee good quality and ensure the best possible shelf life of the products.

During transport, it is also possible to control the atmosphere – to regulate the concentration of gases inside the container such as nitrogen, oxygen and carbon dioxide. This is extremely important when transporting food products, especially such as vegetables and fruits, as the life processes in them change the composition of the atmosphere, which can accelerate their spoilage.

Another curiosity on the subject of reefers are container moisture absorbers, which prevent the formation of so-called container rain, the phenomenon of condensation in a container. They absorb moisture so that the dew point temperature, the temperature at which moisture condenses, is kept below the surface temperature.

Reefer – advantages and disadvantages

Advantages of reefers:

Reefer containers bring many benefits to today’s global trade:

• preserving freshness: they allow fresh food products to be transported over long distances, allowing people around the world to enjoy seasonal flavors.
• increasing efficiency: they make it possible to transport goods in bulk, significantly reducing costs and waste in the supply chain.
• product protection: refrigerated containers ensure the safe transportation of delicate goods, such as pharmaceuticals and chemical products, which require specific storage conditions.

Disadvantages of reefers:

Despite their many advantages, reefers also have some disadvantages:

• high cost: reefer containers are much more expensive than standard containers because they require advanced refrigeration systems.
• energy consumption: it takes a lot of energy to maintain the right temperature during transportation, which can contribute to increased greenhouse gas emissions.
• time constraints: sometimes sea voyages take longer than planned, which can adversely affect product quality.

When planning transportation using them, it is important to keep in mind the limitations of their availability.

Inactive refrigerated containers (NOR)

In transportation, in addition to the use of reefers in a standard manner, situations are also encountered where refrigerated containers are used as standard containers by turning off the chiller. They are mainly used in areas where there is a surplus of reefers, and are sent to regions with a shortage of reefers. As a rule, they are used for return transport – other types of goods are then loaded into empty containers, and this will optimize the cost of the entire delivery. This type of equipment is usually at a discounted price, since the cargo space in a refrigerated container is smaller than in a dry container, due to the space occupied by the aggregate.
However, it should be remembered that in a reefer, due to its construction, damage is easier to occur and more expensive to repair, so special attention should be paid to the gentle handling of the cargo during loading and unloading.

In conclusion, reefers are an indispensable tool in the transportation and food industry, allowing products to be transported in perfect conditions on a global scale. Their evolution from the first simple models to today’s advanced units is an example of the constant technological advances that have helped revolutionize trade and product availability around the world.