Refrigerated Shipping Containers Explained: Design, Applications, and Operating Principles

In the container shipping industry, a refrigerated shipping container is commonly referred to as a reefer container or simply a reefer. These containers are designed to transport temperature-sensitive cargo under controlled conditions.

A standard reefer container is equipped with an integrated refrigeration unit capable of maintaining temperatures as low as −30°C. Some models also feature a built-in heating system, allowing them to maintain temperatures of up to +30°C when required. Depending on the manufacturer and model—such as Thermo King or Carrier—the available temperature range may be even wider.

Reefer containers operate using an external three-phase power supply of 380V or 440V (380V is the European standard, while 440V is commonly used in North America). Modern refrigerated containers also include forced-air ventilation systems to ensure uniform air circulation throughout the cargo space.

What Are Refrigerated Containers Used For?

Reefer containers are essential for transporting products that require strict temperature control throughout the supply chain.

Typical cargo includes:

●      Food products – frozen or chilled meat, seafood, fish, dairy products, fruit, vegetables, and temperature-sensitive beverages.

●      Pharmaceuticals and medical supplies – vaccines, medicines, laboratory samples, and biological materials.

●      Flowers and live plants – fresh-cut flowers, seedlings, and nursery stock.

●      Chemicals and laboratory reagents – products that must remain within a specified temperature range during transport.

How Does a Reefer Container Work?

Unlike a standard dry container, a refrigerated container incorporates several specialized systems that maintain stable environmental conditions during transport.

T-Bar Floor for Uniform Airflow

One of the most distinctive features of a reefer container is its T-bar aluminum floor.

The raised T-shaped floor channels distribute cold air evenly beneath the cargo. Chilled air produced by the refrigeration unit travels through these channels before circulating upward around the entire load.

It is important to understand that a reefer container does not cool warm cargo. Instead, it maintains the temperature of cargo that has already been pre-cooled or frozen.

For this reason, products must be brought to their required transport temperature before loading. Otherwise, the refrigeration unit will be unable to remove heat quickly enough, potentially resulting in cargo spoilage.

Power Supply and Diesel Generator Backup

Under normal operating conditions, reefer containers receive electricity while connected to a vessel, port terminal, or warehouse power supply.

For highly sensitive cargo that cannot tolerate even short power interruptions, reefer containers can be fitted with an external diesel generator (genset).

A genset supplies 400–440 V at 50–60 Hz, ensuring continuous operation during inland transportation, port storage, or power outages.

Modern diesel generator units typically consume approximately 3.1 liters of fuel per hour and can operate for up to five days without refueling, depending on fuel tank capacity and operating conditions.

Ventilation for Fresh Produce

Proper ventilation is just as important as temperature control.

Fresh fruit and vegetables naturally release:

●      Heat

●      Moisture

●      Carbon dioxide (CO₂)

Without continuous air exchange, these gases accumulate inside the container, accelerating ripening, causing dehydration, altering flavor, and shortening shelf life.

Modern reefer units from manufacturers such as Carrier and Thermo King are equipped with dual evaporator fans that generate a high-volume airflow while maintaining the desired temperature.

Humidity Control

Many agricultural and pharmaceutical products require not only stable temperatures but also carefully controlled humidity levels.

Modern reefer containers include dehumidification systems capable of maintaining relative humidity between 60% and 85%, while the newest systems can reduce humidity to approximately 50% when necessary.

This helps prevent condensation, mold growth, and product deterioration during long-distance transport.

Temperature and Humidity Monitoring

Every modern reefer container continuously records operating conditions using electronic sensors and data loggers.

Typical measurements include:

●      Supply air temperature

●      Return air temperature

●      Ambient temperature

●      Relative humidity

Many containers are also equipped with remote monitoring systems, allowing operators to track container performance from anywhere in the world.

For example, Carrier’s DataCOLD™ system records multiple temperature and humidity channels while also logging operational events such as door openings, alarms, and equipment faults.

Drainage System

Although reefer containers operate at low temperatures, moisture still accumulates inside during normal operation.

Condensation forms on the evaporator coils, while fresh produce naturally releases water vapor.

To prevent standing water and cargo damage, reefer containers include four self-sealing floor drains that remove condensation from the cargo compartment while preventing outside air from entering.

Standard Reefer Container Dimensions

Refrigerated containers are manufactured according to international ISO standards.

The table below summarizes the typical internal dimensions and payload capacities of the three most common reefer container sizes.

Average Prices for Refrigerated Shipping Containers

The cost of a reefer container depends on several factors, including:

●      New or used condition

●      Cargo Worthy certification

●      Geographic market

●      Current supply and demand

The table below provides approximate market prices in selected regions.

*The information on this page does not constitute a public offer.