What is Phase Change?

What is Phase Change?

A Phase Change Material (PCM) provides advanced thermal protection when shipping temperature-sensitive products. When PCMs melt and freeze, or change phases of matter between solid and liquid, they maintain a constant temperature equal to their melting/freezing point. They are specially formulated to change phases at specific temperatures to match the payload requirements.

One way to visualize this effect is to think about it in terms of water, which is also used as a PCM. Water’s solid/liquid phase change point is 0°C. In order to keep a product cold in warmer weather, water must be cooled below its phase change temperature until it freezes and becomes ice. When the ice is placed in a package around the temperature-sensitive product, it forms a 0°C thermal barrier between the product and the outside environment’s temperature. The ice begins absorbing the surrounding heat and starts to melt. As the ice melts, it maintains that 0°C temperature barrier and continues to absorb the heat until it has exhausted its thermal capacity and completely liquefies. At this point, the temperature of the water begins to rise above 0°C rapidly until it reaches equilibrium with the ambient temperature.

A Phase Change Material will work the same way to protect the product, but the temperature that it maintains is its own innate melting/freezing point, which will be different than water. For example, a PCM with a phase change point of 5°C is more appropriate for a 2-8°C application because it will maintain a temperature within the application range, whereas water will not at 0°C.

One of the most important things to keep in mind when utilizing a phase change material is its optimal starting temperature condition. Certain applications might require you to condition your PCM as a solid prior to shipment, while others will require you to condition as a liquid. This is dependent on whether heat is overall being gained or lost by the package during shipment. (The Cryopak team can guide you to the proper conditioning method for your application.)

Whether a product needs to be kept frozen, refrigerated or at room temperature, Cryopak offers a variety of Phase Change Materials that are safe and effective thermal management solutions for products shipped within the cold chain.

To learn more about phase change materials, visit our product pages:

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