Views: 2 Author: Site Editor Publish Time: 2023-04-13 Origin: Site
A refrigerated container or reefer, is an intermodal container (sea container) used for intermodal freight, capable of being refrigerated to transport temperature-sensitive, perishable goods such as fruit, vegetables, meat, and other similar items.
While reefers will have an integral refrigeration unit, they rely on external power, from a power point (“refrigerated point”) at a land-based site, container ship, or dock.When transported by road by trailer or rail wagon, they may be powered by diesel generators ("gensets") that are connected to the container during the road trip.Refrigerated containers are capable of controlling temperatures from −65 °C (−85 °F) to 40 °C (104 °F).Some reefers are equipped with a water cooling system which can be used if the reefer is stored below deck on a boat without adequate ventilation to remove the heat generated.
Water-cooling systems are more expensive than airflow ventilation, which removes heat from the cargo hold, and the use of water-cooling systems is decreasing.Air cooling and water cooling are often used in combination.The impact of refrigerated containers on society is enormous, allowing consumers around the world to enjoy fresh produce at any time of the year and experience fresh produce that was previously unavailable in many other parts of the world.
Another type of refrigeration system sometimes used where travel times are short is total loss refrigeration, where frozen carbon dioxide ice (or sometimes liquid nitrogen) is used for cooling. The cryogenically frozen gas slowly evaporates cooling the container and venting it.The container will be cooled as long as there is refrigerated gas available in the system.These have been used in rail cars for many years, providing up to 17 days of temperature regulation.While refrigerated containers are uncommon in air transport, total loss dry ice systems are commonly used.These containers have a chamber containing solid carbon dioxide, the temperature of which is regulated by thermostatically controlled electric fans, and the air version is designed to maintain the temperature for up to 100 hours or so.A full-size intermodal container equipped with these "cryogenic" systems can maintain the temperature for the 30 days required for ocean transport.Since they require no external power source, cryogenic refrigerated containers can be stored anywhere on any vessel that can accommodate "dry" (non-refrigerated) sea containers.
Valuable temperature-sensitive or dangerous goods often require the highest system reliability.This kind of reliability can only be achieved by installing redundant cooling systems.A redundant cooling system consists of an integrated primary cooling unit and a backup cooling unit.If the primary unit fails, the secondary unit starts up automatically.In order to provide reliable power to the refrigeration unit, these containers are usually equipped with one or more diesel generator sets.Containers fitted with these systems may be required to transport certain dangerous goods in order to comply with IMO regulations.