Phase-change material

Common card · No. 311030

A phase-change material (PCM) is a substance which releases/absorbs sufficient energy at phase transition to provide useful heat or cooling. Generally the transition will be from one of the first two fundamental states of matter - solid and liquid - to the other. The phase transition may also be between non-classical states of matter, such as the conformity of crystals, where the material goes from conforming to one crystalline structure to conforming to another, which may be a higher or lower energy state. The energy required to change matter from a solid phase to a liquid phase is known as the enthalpy of fusion. The enthalpy of fusion does not contribute to a rise in temperature. As such, any heat energy added while the matter is undergoing a phase change will not produce a rise in temperature. The enthalpy of fusion is generally much larger than the specific heat capacity, meaning that a large amount of heat energy can be absorbed while the matter remains isothermic. Ice, for example...

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