Temperature Control in Passive Cold Chain Shipping Containers

To learn about cold chain shipping containers, let's start with a definition taken from the World Health Organization (WHO) publication "Model requirements for storage and transport of time- and temperature-sensitive pharmaceutical products".

Active systems:

Active systems powered using electricity or another fuel source to maintain the temperature-controlled environment inside an insulated enclosure under thermostatic regulation (eg cold rooms, refrigerators, temperature-controlled trucks, sea, and air-cooled containers). If your business also requires cold storage facilities, you should check out cold rooms available for hire at https://www.coolroomhireperth.com.au/

Passive systems: Systems that maintain the temperature-controlled environment inside an insulated enclosure, with or without thermostatic regulation, using a limited number of pre-conditioned coolant in the form of chilled or frozen gel packs, phase change material, dry ice or others.

Both of these definitions refer to "thermostatic regulation" which is active temperature control. thermostat provides the intelligence in the container to make the decision to activate the cooling when the temperature inside the insulated enclosure rises and deactivate cooling when the internal temperature drops.

In the cold chain shipping industry, the normal tendency has been to think that the system should be an active system to have active temperature control, but such is not the case. I applaud the WHO to include the phrase "with or without thermostatic control" in the definition of a passive system.