PCM – Phase Change Material
PCM stands for phase change material. During a solid–liquid phase change, the material absorbs heat as it melts and releases heat as it solidifies. A large amount of energy can be transferred while the material’s temperature changes only slightly. This energy is known as latent heat.
Why does the melting range matter?
- A suitable phase change range enables heat to be buffered close to the required operating temperature. It must suit the application and the packaging design.
- Water is also a PCM. In temperature-controlled shipping, the term often refers to specially formulated media with melting points other than approximately 0 °C.
- The amount of material and its initial state are just as relevant to the available buffering capacity as its material properties. Preparation is explained under pre-conditioning.
Does PCM keep the product temperature exactly constant?
No. Material temperature and product temperature are different quantities. Heat transfer, arrangement, loading and ambient conditions affect the temperature history. Storage capacity is also limited. Any claimed protection duration therefore requires evidence from the complete packaging system.
Related terms: PCM coolant pack · Volumetric heat capacity
Technical references:
OpenStax: Phase change and latent heat