Before potential container solutions can be considered, you must first define the shipment parameters. This is true whether you are shipping internationally or domestically. The shipment parameters will help you narrow down the vast array of thermal containers available today.  Some of the parameters that should be considered are:

• Interior temperature range (i.e. refrigerated between 2° and 8° C).
• Geographical origin and destination.
• The external ambient temperatures that the container will be exposed to in the summer and winter.
• Expected duration of the shipment.
• Size and weight of the payload.
• Recipient (depot, clinic, individual etc…).
• Material restrictions (no dry ice allowed etc…).
• Shipment value (dollar cost and ability to replace).
• Expected container durability.

After defining and prioritizing these parameters, you are in a position to evaluate potential thermal container solutions that will fit your needs.  There are three basic categories of thermal containers available to consider: passive containers, active containers, and hybrid containers.

Active containers utilize electronic and mechanical means (usually compressors) to maintain the interior temperature. The advantages of these containers are their large capacity, simple or nonexistent pack-out, and the ability to maintain temperature for long durations. The disadvantages are that their moving or electronic components can fail, batteries need to be replenished, their inaccessibility to some destinations, and the very high expense associated with their use.

Hybrid containers utilize electronic controls to meter a passive phase-change material (PCM), usually dry ice, to maintain the interior temperature.  The advantages and disadvantages to these containers are similar to the active containers.  One additional disadvantage is that dry ice is considered a hazardous substance, and special precautions must be taken when utilized.

Finally, we have the passive containers, which can be further broken down into traditional and advanced thermal containers that utilize insulation and passive PCM to maintain the interior temperature. Traditional passive containers utilize some type of foam insulation and water-based gel packs or dry ice as a PCM.  The advantages of traditional passive containers are their low cost, which makes them great for short duration one-way shipments. The disadvantages are that they generally lack the duration and temperature stability required for international shipments, and they are physically large and heavy and have complex or multiple pack-outs for different situations.

Advanced passive thermal containers, like the ones developed by Minnesota Thermal Science, utilize new high-tech insulation options like vacuum insulation panels (VIPs) and custom-formulated high-performance PCMs designed to hold tight and precise temperature ranges for extended periods of time.  The advantages of these containers are their simplicity, long duration, size ranges, minimal temperature stratification within the payload area, and reusability.  The disadvantage to using these containers is that the PCM must be conditioned prior to use, so freezer equipment must be available to accommodate this step. Another challenge is receiving the container back for reuse, which increases your ROI and keeps waste out of our landfills. Reuse is certainly a challenge is some situations depending on the type of recipient, but offers a significant environmental advantage and increases the ROI.

Compare the advantages, disadvantages, and capabilities of the different types of containers available to you with the shipment parameters that you have defined to narrow down your options to the two or three that will best meet your needs. Carefully review the thermal and transportation qualification data that the manufacturer has provided and be prepared to execute some qualification testing of your own (which is another subject all together) to properly select and qualify your final solution. With proper research, planning, and execution, your international cold-chain shipments can and will be successful.