Reefer container is short for the refrigerated container, also abbreviated as RF container. A refrigerated container is a shipping container that remains its cargo at a regulated, cool temperature. A reefer usually works at a temperature range of -30°C and +30°C and handles frozen, chilled, or cold goods. Special refrigerated containers (super freezers) can maintain a temperature down to -70° C (further reading: Reefer operations - How to optimize efficiency and safety).

Usually, a reefer has his refrigeration unit. This unit needs power to generate chilled airflow, maintaining the desired temperature and humidity.

How dose Reefer container work

As the refrigeration of the container is done by air, airflow is the most vital part of a reefer container. The generator blows cold air along the floor or side into the container on one side of the reefer. The floor is T-shaped and distributes the airflow below the cargo unobstructed. As a result, the cold air ascends and returns on top of the load on the other end of the reefer container. That said, a reefer container maintains the pre-cooled temperature of the cargo, but it cannot reduce the temperature of the cargo! In other words: a load of a reefer container has to be brought to the desired temperature before loading.

Components of a reefer shipping container

• Interior fans: Interior fans are installed inside the refrigerated container and help spread air to promote adequate temperature control and stability.
• Control unit: The control unit sets and adjusts the internal climate of the reefer container, including the temperature, alarm conditions, and in some cases, ventilation and humidity levels.
• Fresh air vent: The fresh air vent hole lets air enter from outside, and any gases from the container, such as fruit-ripening ethylene gas, can leave.
• Unit evaporator: Excess moisture in a reefer can harm products, quicken food spoilage and break down packaging, leaving contents vulnerable. The unit evaporator helps preserve the humidity inside the container. The reefer unit evaporator can either heat or cool the air that circulates past it from the fan. Heating capacity is using either hot gas heat or electrical heating elements.
• Condenser: Air-cooled models pull cooled air from the top of the container and discharge it under the cargo, pushing the air to the back doors before it convects naturally and rises, flowing back over the load to the return air inlet on the reefer unit. Because air moves under the cargo, proper loading and covering as much of the floor as possible is critical to prevent a “chimney” effect and short cycling.
• Voltage transformers: Dual voltage transformers are also an option with some containers, allowing operation on voltages down to 200V.