ShareRefrigerated containers: state of play and perspectives
Refrigerated containers play an essential role in the maritime refrigerated transport sector; a look back at the stages of their development and the recent and future technological advances of this technology.
The introduction of refrigerated containers in the 1970s deeply transformed the maritime transport industry for temperature-sensitive products. This technology is also the subject of numerous developments in terms of design, operation and control.
Brief history
[1] During the first half of the 19th century, ice was used to keep food cold during transport. Additionally, fishing boats used large amounts of ice to keep their catches fresh. The ice was obtained by cutting it from frozen lakes in Maine in the United States, Canada or Scandinavia. In 1890, the ice trade reached its peak with over 500 vessels employed, mainly powered by sail. [1]
It was in the mid-1860s that two Frenchmen, Ferdinand Carré and Charles Tellier, first experimented with mechanical refrigeration. They used first an ammonia absorption freezing plant on the ship City of Rio de Janeiro, then an ammonia compression plant on the ship "Le Frigorifique", with some success. [1]
The first refrigerated ships specially designed for the transport of bananas, like the Port Morant, appeared in 1901. CO2 machines were used to lower the temperature and control it. This represented a breakthrough for the transportation of temperature-sensitive fruits. [2]
In the mid-1930s, the first portable air-cooling unit was designed by the American Fred McKinley Jones, and it was not until the 1950s and 1960s that the true golden age of refrigerated containers entered, a real revolution in the world of maritime transport. Refrigerated transport was then much better controlled and new foodstuffs, such as tropical fruits or even meat, could be shipped across any ocean. [2]
The 1970s saw the arrival of refrigerated containers specially designed to be transported by container carriers. Refrigerated containers came in many different shapes and sizes, each equipped with its own separate cooling units controlling the interior atmosphere. On board a ship, refrigerated containers were plugged into the onboard electrical power system. In terminals or when transported inland, they were connected to reefer plug points or equipped with generators. This system is still widely used today in the cold chain. [2]
The essential place of refrigerated containers
Refrigerated containers play a vital role in the global supply chain. Usable over a temperature range between -30°C and +30°C, they allow many types of heat-sensitive products to be transported at constant temperature, primarily food products (fruit, vegetables, meat, etc.) over very great distances [3].
While the share of goods transported by sea in conventional containers is slightly increasing worldwide, the refrigerated container transport segment is currently experiencing a marked increase [4].
According to Allied Market Research [5], the reefer container industry generated $9.7 billion in 2022 and is expected to generate $19.7 billion by 2032, growing at a CAGR of 7.5% from 2023 to 2032.The maritime segment held the highest market share in 2022, accounting for almost two-thirds of the global refrigerated container market revenue.
Recent technological developments and challenges ahead
Refrigerated container technology is likely to be constantly developing as new challenges emerge. These advances concern, on the one hand, the design of containers and, on the other hand, the operation and control of this equipment.
In terms of design, we can thus highlight the increasingly frequent use of light and durable materials such as bamboo for the manufacture of shipping container floors. This is the case, for example, of the French company CMA CGM [6].
We can also very recently note the launch by the Japanese company Ocean Network Express [7] of the first dual-temperature refrigerated container in the world equipped with controlled atmosphere technology. A removable divider allows the container to be separated into two zones with different temperatures over a range of -30°C to +30°C.
In terms of controlling and regulating the operating parameters of these containers, the advances are spectacular and should continue to follow one another, particularly due to the growing application of Artificial Intelligence (AI) and the Internet of Things (IoT).
The operating parameters to be controlled are numerous and represent considerable financial issues linked to the risk of damage to the cargo in the event of a failure [8].
Airflow, which ensures container cooling, is the most crucial part of a refrigerated container. Besides air temperature control, effective ventilation is another essential feature of a shipping refrigerated container. Fruits, vegetables and plants release CO2, water, heat and ethylene. If these components are not removed, they can spoil the cargo by causing uncontrolled ripening, aging and flavour alteration. Therefore, refrigerated containers are kept ventilated with fresh air. Humidity also plays a significant role in the safety of goods. A dehumidification system maintains the correct humidity levels in the container [8].
To control all these parameters as well as the power supply, microprocessors continuously record and transmit data by using remote modems. Monitoring of the first refrigerated containers was carried out using fairly simple technologies. This mainly involved maintaining the desired temperature using mechanical cooling systems. Over time, more and more advanced sensors have been used [9].
Today, real-time monitoring, alarm systems and remote management are standards. Smart refrigerated containers, equipped with IoT (Internet of Things) sensors, enable real-time monitoring of temperature, humidity and other major environmental factors without the need for external devices [9].
These technological advances create new risks linked to data security and cybersecurity in general but also generate improvements at a high level, difficult to imagine until recently, in particular thanks to artificial intelligence (AI). AI helps analyse sensor data and can predict when a refrigerated container is likely to fail or require maintenance. This approach reduces the risk of refrigerated container failure during transport and damage or deterioration of the goods. Predictive maintenance not only improves reliability, but also optimises energy consumption [9].
However, predictive maintenance is just one example of an application of AI. It is likely that in the future, even more tasks will be assigned to it, such as predictive analysis based on all monitored parameters, optimisation of performance and energy efficiency, route optimisation, integration with supply chain management [9].
Sources:
[1] https://www.freightwaves.com/news/maritime-history-notes-150-years-of-refrigeration
[2] https://www.linkedin.com/pulse/didyouknow-short-history-refrigerated-container-lidia-slawinska
[3] https://www.identecsolutions.com/news/101-reefer-container
[4] https://www.sciencedirect.com/science/article/pii/S1877050922013084
[6] https://www.bipiz.org/fr/bonnes-pratiques/cma-cgm-des-conteneurs-ecologiques-entrent-en-flotte.html
[8] https://www.identecsolutions.com/news/101-reefer-container
[9] https://www.identecsolutions.com/news/trends-reefer-monitoring