Summary:
A reefer container is a temperature-controlled shipping container designed to store and transport perishable goods like food, pharmaceuticals, and industrial chemicals. It maintains a regulated temperature (-30°C to +30°C) using integrated refrigeration systems and ventilation controls. In contrast, a dry container is a non-refrigerated unit used for general cargo transport, including electronics, furniture, and construction materials.
While reefer containers are more expensive due to their cooling technology, they prevent spoilage and ensure cargo integrity. Dry containers are cost-effective and durable, making them ideal for bulk shipping of non-perishable goods. Choosing the right container depends on your cargo’s temperature sensitivity and shipping needs.
Introduction
The shipping container is arguably one of the 20th century’s most revolutionary modular products. Currently, shipping containers continue to transform the world’s economy by facilitating inter-continental transportation of high-value products. These include electronic equipment, perishable food products, and even pharmaceuticals.
Generally, there are two main types of shipping containers that underpin global transportation, dry containers and reefer containers.
Today’s article will compare reefer and dry containers, examine their specifications, discuss their applications.
What are reefer containers?
Offshore reefer containers, also known as refrigerated containers, are fundamentally regular shipping containers that are temperature-controlled and designed to store and transport perishable goods under regulated conditions. Reefers can sustain stable temperatures with controlled humidity levels and adequate airflow mechanisms.
Their specialised features help keep perishable goods in pristine condition, protecting them from spoilage due to excessive cold, humidity, heat, or even lack of adequate airflow.
Reefer Container Specifications
- Temperature range: Typically maintain a temperature range of -60°C to +30°C depending on the type.
- Humidity & ventilation control: Prevents condensation and maintains airflow.
- Sizes: Offshore reefer containers are commonly available in 8FT, 10FT, 20FT, and 40FT sizes
- Compliance: DNV 2.7-1 certification is essential for offshore operations, ensuring safety and compliance with industry standards.
How does a reefer container work?
Reefer containers maintain precise temperatures, typically between -30°C and +30°C, using a refrigeration unit powered by an external source or a generator. This unit circulates cooled air within the container, while ventilation systems prevent condensation and ensure even temperature distribution. Humidity levels are also controlled to preserve cargo quality.
Advanced monitoring systems allow real-time tracking and remote adjustments of temperature and other parameters. Backup power systems, such as batteries or diesel generators, can maintain the desired environment for a limited time if the primary power source is interrupted.
Read more on remote temperature monitoring for offshore reefer containers here.
Uses of refrigerated containers
Refrigerated containers provide an optimal low air temperature environment to store frozen goods that require temperatures of at least -5 degrees Celsius. For example, ice cream, meat products like poultry and pork, or frozen seafood like salmon and tuna.
Furthermore, they provide an optimal environment for chilled products that need to be shipped at low temperatures but don’t require freezing. For example, dairy, confectionery, eggs and fruits and vegetables.
They also provide a storage and transportation medium for extremely temperature-sensitive products like pharmaceuticals, batteries, industrial chemicals and tobacco.
What is a dry shipping container?
A dry container is essentially a standard non-refrigerated shipping container used to accommodate dry, non-temperature-sensitive and non-hazardous shipments. Typically 40′ in size, these containers constitute strong steel to resist rain, wind and saltwater elements.
What are dry containers used for?
Because dry containers are strong, versatile, and durable, they are extensively deployed for bulk international shipping tasks that typically involve non-perishable items. For example, electronics, vehicles, furniture and non-perishable foodstuffs.
Are dry containers the same as insulated containers?
As already mentioned, dry containers are standard containers used to transport items that aren’t impacted by temperature, or humidity.
On the other hand, insulated containers are specialised containers used to transport items that require safeguarding from thermal shocks, humidity infiltration, odours, condensation, and cross-contamination.
Insulated containers are not designed to refrigerate or heat goods, but prevent damaging spikes or dips in temperature that could damage products. Principally, they are designed to offer optimal protection from contamination, without compromising on space or eco-friendliness.
Reefer container vs dry container: Key differences
Cost
Because of their specialised electronic components, reefer containers are more expensive to hire, maintain or purchase than dry containers. However, their temperature-controlled shipping capabilities make them much more cost effective in the long term than dry containers.
The cost of a reefer container depends on reefer container dimensions, insulation quality, and cooling capacity. For example, a DNV 2.7-1 10ft offshore refrigerated container is specifically designed for offshore logistics and compliance with marine safety standards, making it an ideal choice for offshore frozen container transport.
Durability
Reefer containers are highly durable as they can be used even in adverse weather conditions. However, compared to dry containers, they can be slightly less durable due to the presence of refrigeration components.
This could be because dry containers are predominantly made of aluminium or steel to handle large payloads. Since they do not constitute any specialised electronics which could break down fewer components require maintenance or repair.
MGS Offshore Mini Reefer Containers. Ready stock and quotation in 24 hours.
Purpose and application
Reefer containers are mainly utilised to transport perishable and temperature-sensitive items. Common applications include:
- Pharmaceuticals: Medicine, multivitamin supplements, and some medical tools and supplies.
- Food and beverage: Meats, dairy products, fruits, vegetables, chocolate and seafood.
- Disaster relief: Reefer shipments can be used during natural disasters to deliver aid, such as medicine and food, to communities that may otherwise be highly challenging to ship on short notice.
- Military and government application: Essential for storage and transport at testing sites and deployment areas in order to meet stringent safety standards for electromagnetic interference and vibration resistance exercises.
Dry container uses
Dry containers are used to transport and store non-perishable or dry items. In fact, dry containers are mainly suited to products that aren’t liquid, gas, or hazardous if mishandled. For example:
- Books and paper products.
- Toys.
- Sand.
- Furniture
- Vehicle parts.
- Coal and stone.
- Grains,sugars and salts.
- Building materials.
- Clothing.
- Tools and equipment.
Technology
Reefer containers use many of technological components. Most models are equipped with controller units that adjust the temperature, humidity, and ventilation settings for disparate cargo types.
Reefer container ventilation prevents condensation and maintains airflow, while data loggers and GPS tracking enable real-time monitoring.
Read more about how GPS tracking systems are used for offshore reefer container logistics here.
On the other hand, dry containers rarely have any electronic components and come in standard formats. They do not require controller units or exchange systems to maintain optimal oxygen levels and keep products fresh.
Which shipping containers are best for my business?
As mentioned above, both reefer and dry containers are similar that they both offer a fast and efficient bulk shipping medium for transporting items across land and sea.
However, reefers tend to have multiple temperature control mechanisms, making them ideal for temperature-sensitive cargo. In contrast, dry containers are designed for non-perishable items, offering a cost-effective solution for heavy loads.
That said, the choice between the two depends on your business needs. If your products are non-hazardous and do not require refrigeration, then a dry container might be a more cost-efficient option when dealing with heavy loads.
However, if your cargo is perishable, environmentally sensitive, or requires temperature regulation, then an offshore reefer container is the best option to remain safely compliant with local and industry regulations.
Frequently Asked Questions (FAQs)
How does a refrigerated shipping container work?
Reefer containers use integrated cooling units powered by external electrical sources to regulate temperature, humidity, and airflow.
What are the size options for reefer containers?
Reefer containers are available in 10ft, 20ft, and 40ft sizes and can withstand temperatures from -30°C to +30°C.
Why are reefer containers more expensive than dry containers?
Reefers have advanced cooling systems and insulation, which increase their cost. However, they reduce product spoilage and maintain cargo integrity, making them cost-effective for businesses handling perishable goods.
What gas is used in reefer containers?
Most reefer containers use R-134a, R-404A, or R-452A refrigerants, ensuring efficient cooling while complying with environmental regulations.
How cold can a reefer container get?
A reefer container can maintain temperatures as low as -30°C, while super freezer reefer containers can go as low as -60°C for high-value frozen cargo like seafood and pharmaceuticals.
How long can a reefer container be unplugged?
A reefer container can remain unplugged for 12-24 hours, depending on insulation quality, ambient temperature, and cargo type. For extended periods, backup power sources like diesel generators are used to maintain the reefer container temperature.
What industries use reefer containers?
Reefers are widely used in food & beverage, pharmaceuticals, chemical, and logistics industries for the safe transportation of temperature-sensitive products.
Conclusion
Dry containers are primarily employed to transport general dry commodities, offering a cost-effective and durable solution for bulk shipments. In contrast, reefer containers are well suited for moving temperature-sensitive products, ensuring precise climate control to prevent spoilage.
Depending on the sensitivity of your cargo, you can choose between the two container types to determine which suits your business needs. If your shipments require temperature regulation, a reefer container is the ideal choice. For non-perishable cargo, a dry container provides an economical and efficient solution.
Looking for the right shipping container? Explore MGS Offshore’s selection today!
Business Director
A graduate (Business) from KDU, Jason Tan, is the current Business Director (Sales) for MGS Icestorm and has been associated with the company for the past 10 years.
With over 13 years in the shipping industry, he has had a significant contribution to Malaysia’s oil and gas industry in the engine and boat supply sector.
His expertise includes managing offshore catering business, offshore reefer containers, AI technology, offshore gas tanks, A60 pressurized cabins, etc. His contributions have helped establish MGS, in partnership (joint venture) with Thermo King and Honeywell to produce state of art Offshore Reefer Container products.