Thermally Protective Packaging: Five Essentials Of Gel Refrigerant Design And Specification

By Anthony Alleva, TCP Reliable, Inc. and Karen K. Greene, Life Packaging Technology LLC

Temperature controlled packaging is used throughout many industries to protect temperature sensitive products. These are products especially sensitive to fluctuations in temperature. The industries utilizing temperature sensitive packaging range from highly engineered biotechnology products to gourmet cakes and fish. Designing temperature sensitive packaging requires a level of analysis as detailed as any other type of shipping package. What are the design requirements of the product/device/item being shipped, where is it going and what are the anticipated hazards that can render your product at the minimum, unfit to eat and at the extreme, a compromised biotechnology product, combination drug/device or pharmaceutical which can no longer guarantee the safety and efficacy of the medical product for the patient. The temperature controlled packaging industry has developed some very effective thermally insulative designs utilizing several forms of insulated containers and refrigerant packs. This report will focus on five essentials of gel refrigerant design and specification vital to optimizing thermal protection for your temperature sensitive product while achieving this in a timely and cost effective manner.

The refrigerant pack or gel pack is used to power your insulated shipping container to maintain a thermal environment sufficient to meet the product’s temperature requirements. A few thermodynamic concepts are involved here: heat transfer, heat absorption and phase change. These principles are some of the components of the “zeroth law” of thermodynamics, commonly known as thermal equilibrium. That is, all systems attempt to reach a state in which heat energy is equally distributed. If an object with a higher temperature comes in contact with a lower temperature object, it will transfer heat to the lower temperature object.