Reefers, short for refrigerated containers, are a type of modular shipping and freight container with an internal cooling system used by food distributors to transport perishable goods over long distances. Each unit is designed to maintain a consistent temperature while being transported via ground or over seas.
All reefers are equipped with internal cooling systems that consist of an air cooling system and thermostat for monitoring and controlling internal temperatures. Many reefers are capable of maintaining any temperate from minus 25 degrees Celsius to 25 degrees Celsius. Each unit also requires an outside power source to operate the cooling unit. While in transport on ships or being held in a loading dock, the containers utilize electrical power. During ground transportation, the containers are configured to use the same diesel fuel that the cargo trucks use.
Due to the cramped spaces and poor ventilation of many cargo ships, some reefers are equipped with water cooling systems. The water cooling system reduces the amount of heat produced by the cooling unit, and thus keeps the storage environment dry and free of bacteria. This type of configuration is expensive to manufacture and maintain, which has lead to a greater emphasis on ventilation and air circulation in modern cargo ships.