Types of pharmaceutical cold chain shipping containers
There is considerable confusion about the classification of cold chain shipping containers for shipping pharmaceuticals. The terms “active systems”, “active systems – compressor”, active systems – dry ice”, “semi-active systems”, “passive systems”, “dry ice systems”, and “hybrid systems” have all been used to classify cold chain shipping containers.
In my opinion, cold chain shipping containers fall into two types:
- Containers that do not contain intelligent temperature control capability (passive temperature control).
- Containers that have intelligence to start and stop cooling as necessary based on the internal temperature of the container (active temperature control).
Passive Temperature Control
Passive temperature control applies to packages that do not have any intelligence to regulate the cooling process. The phase change material (PCM) used in passive systems is always cooling no matter what the internal temperature is. The system is designed based on the premise that the heat leaking into the package will be approximately equal to the cooling capacity of the phase change material in the package. The equilibrium condition resulting from this situation will keep the internal temperature within the desired temperature range.
Active Temperature Control
Active temperature control applies to packages that have intelligence to start and stop cooling based on the internal temperature of the package.
Active temperature control packages fall into the following types:
- Uses a compressor. A thermostat starts and stops the compressor to regulate the temperature. This package is battery powered.
- Uses a fan to circulate air over dry ice or frozen water containers. A thermostat starts and stops the fan to regulate the temperature. This package is battery powered.
- Uses a mechanical thermal switch to control cooling using frozen water as the cooling medium. A thermostat causes a mechanical thermal switch to open or close a thermal conduction conduit to regulate the temperature. This package does not require battery power.
Passive temperature control technology has been around for many years and in some situations passive systems are still an economical solution. However, for high value payloads on international shipments, this technology is not the best solution.
Passive temperature control packages are the reason for having all the different pack out protocols for winter, summer, ship hot – arrive cold, and ship cold – arrive hot. The package does not have the intelligence to make adjustments for different ambient environments. Probably the most challenging shipment is to ship from the northern hemisphere to the southern hemisphere or visa versa in February. This will be an international shipment of several days including customs clearance. For example, consider a shipment from Minneapolis, MN to Rio de Janeiro, Brazil. (Leave cold – arrive hot profile). This shipment presents a very difficult challenge for a passive package.
On the other hand, an active temperature controlled package has the intelligence to stop cooling when the internal temperature is low and to start cooling when the internal temperature rises. The pack out protocol for an active temperature controlled package is the same for any shipment since the package adjust its cooling or heating (if heating is included in the package) automatically.
Currently, most of the active temperature controlled packages are pallet sized units such as the AcuTemp® RKN Thermal Pallet Shipper and the Environtainer® RKN. The Envirotainer® CLD is somewhat smaller than a full pallet load container.
However, there are only two small package active temperature controlled units of which I am aware. The AcuTemp® AX27L Mobile Temperature Management Unit (27 liter payload) is a small payload volume active temperature controlled shipper. It uses a battery driven compressor for controlling the temperature.
The other small active temperature controlled units are Kodiak™ containers ( 36 liter and 11 liter payload) made by Active CC Boxes, LLC. These units use a thermostat controlled thermal switch to regulate the internal temperature.
For relatively low value domestic shipments in predictable shipping situations, the passive shipping container is still a viable option. However, for international shipments where the shipping situation becomes unpredictable (customs delays) and the temperature differences can be more challenging, strongly consider using a package with active temperature control.