How a Reefer (or Refrigerated Container) Works

Thermometer on snow shows low temperatures under zero. Low temperatures in degrees Celsius and fahrenheit. Cold winter weather twenty under zero.Thermometer on snow shows low temperatures under zero. Low temperatures in degrees Celsius and fahrenheit. Cold winter weather twenty under zero.

In transport, a reefer means a refrigerated container. These are most often used to move produce – fruits, vegetables, frozen chickens, pizzas. If you refrigerate it for transport, a reefer is a good way to do it, but there are a few considerations involved.

Air Cooling

In order to maintain a consistent and even temperature, air has to be circulated within the reefer unit. In order to do this, there are clearances above and below the cargo itself. Below the cargo, grates leave room for air to travel. That air travels up as it warms (only compared to the rest of the air in the container; it’s still very cold). The clearance inside the container that’s above the cargo allows that air to cycle back to the refrigeration unit, which re-cools it and pushes it into the bottom of the container under the grating (and thus pushes the slightly warmer air up to maintain the cycle).

Power

This is all maintained by a power source. In major forms of refrigerated transportation, a backup power source is always maintained. Should the primary power source fail with no backup, hundreds of thousands or even millions of dollars of product would warm up with no ability to keep them cool. This is exactly why a backup power source (and often a tertiary one as well) is always maintained. Road transport employs clip-on or underslung generators to keep a reefer cold.

Reflectivity

Simple decisions in terms of efficiency help this process and allow power to be used efficiently. For instance, reefers are painted white. Just as a black car will heat up more rapidly than a white car, so would a refrigerated container painted black. White reflects sunlight rather than absorbing it, meaning that white reefers aren’t absorbing as much heat as they would if painted black.

Refrigerated transport is key to certain routes, such as exports from Central America, from which other countries receive a great deal of their produce. Refrigerated transport is chiefly utilized for produce, but it can be utilized in other ways as well – for chemical and medical supply transport as well.